io.minio.MinioClient.java Source code

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/*
 * Minio Java Library for Amazon S3 Compatible Cloud Storage, (C) 2015 Minio, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.minio;

import com.google.common.io.ByteStreams;
import com.google.gson.Gson;
import com.squareup.okhttp.HttpUrl;
import com.squareup.okhttp.MediaType;
import com.squareup.okhttp.OkHttpClient;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.RequestBody;
import com.squareup.okhttp.Response;
import io.minio.errors.ErrorResponseException;
import io.minio.errors.InsufficientDataException;
import io.minio.errors.InternalException;
import io.minio.errors.InvalidArgumentException;
import io.minio.errors.InvalidBucketNameException;
import io.minio.errors.InvalidEndpointException;
import io.minio.errors.InvalidExpiresRangeException;
import io.minio.errors.InvalidObjectPrefixException;
import io.minio.errors.InvalidPortException;
import io.minio.errors.NoResponseException;
import io.minio.errors.NoSuchBucketPolicyException;
import io.minio.http.HeaderParser;
import io.minio.http.Method;
import io.minio.http.Scheme;
import io.minio.messages.Bucket;
import io.minio.messages.CompleteMultipartUpload;
import io.minio.messages.CreateBucketConfiguration;
import io.minio.messages.ErrorResponse;
import io.minio.messages.InitiateMultipartUploadResult;
import io.minio.messages.Item;
import io.minio.messages.ListAllMyBucketsResult;
import io.minio.messages.ListBucketResult;
import io.minio.messages.ListMultipartUploadsResult;
import io.minio.messages.ListPartsResult;
import io.minio.messages.Part;
import io.minio.messages.Prefix;
import io.minio.messages.Upload;
import io.minio.org.apache.commons.validator.routines.InetAddressValidator;
import io.minio.policy.BucketAccessPolicy;
import io.minio.policy.BucketPolicy;
import io.minio.policy.Statement;
import okio.BufferedSink;
import okio.Okio;
import org.apache.commons.collections4.CollectionUtils;
import org.joda.time.DateTime;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlPullParserFactory;

import java.io.BufferedInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.RandomAccessFile;
import java.io.StringReader;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.nio.file.StandardOpenOption;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * <p>
 * This class implements a simple cloud storage client. This client consists
 * of a useful subset of S3 compatible functionality.
 * </p>
 * <h2>Service</h2>
 * <ul>
 * <li>Creating a bucket</li>
 * <li>Listing buckets</li>
 * </ul>
 * <h2>Bucket</h2>
 * <ul>
 * <li> Creating an object, including automatic upload resuming for large objects.</li>
 * <li> Listing objects in a bucket</li>
 * <li> Listing active multipart uploads</li>
 * </ul>
 * <h2>Object</h2>
 * <ul>
 * <li>Removing an active multipart upload for a specific object and uploadId</li>
 * <li>Read object metadata</li>
 * <li>Reading an object</li>
 * <li>Reading a range of bytes of an object</li>
 * <li>Deleting an object</li>
 * </ul>
 * <p>
 * Optionally, users can also provide access/secret keys. If keys are provided, all requests by the
 * client will be signed using AWS Signature Version 4.
 * </p>
 * For examples on using this library, please see
 * <a href="https://github.com/minio/minio-java/tree/master/src/test/java/io/minio/examples"></a>.
 */
@SuppressWarnings({ "SameParameterValue", "WeakerAccess" })
public final class MinioClient {
    private static final Logger LOGGER = Logger.getLogger(MinioClient.class.getName());
    // maximum allowed object size is 5TiB
    private static final long MAX_OBJECT_SIZE = 5L * 1024 * 1024 * 1024 * 1024;
    private static final int MAX_MULTIPART_COUNT = 10000;
    // minimum allowed multipart size is 5MiB
    private static final int MIN_MULTIPART_SIZE = 5 * 1024 * 1024;
    // default expiration for a presigned URL is 7 days in seconds
    private static final int DEFAULT_EXPIRY_TIME = 7 * 24 * 3600;
    private static final String DEFAULT_USER_AGENT = "Minio (" + System.getProperty("os.arch") + "; "
            + System.getProperty("os.arch") + ") minio-java/" + MinioProperties.INSTANCE.getVersion();
    private static final String NULL_STRING = "(null)";
    private static final String S3_AMAZONAWS_COM = "s3.amazonaws.com";
    private static final String AMAZONAWS_COM = ".amazonaws.com";
    private static final String END_HTTP = "----------END-HTTP----------";
    private static final String US_EAST_1 = "us-east-1";
    private static final String UPLOAD_ID = "uploadId";
    private static final Gson gson = new Gson();

    private static XmlPullParserFactory xmlPullParserFactory = null;

    static {
        try {
            xmlPullParserFactory = XmlPullParserFactory.newInstance();
            xmlPullParserFactory.setNamespaceAware(true);
        } catch (XmlPullParserException e) {
            throw new ExceptionInInitializerError(e);
        }
    }

    private PrintWriter traceStream;

    // the current client instance's base URL.
    private HttpUrl baseUrl;
    // access key to sign all requests with
    private String accessKey;
    // Secret key to sign all requests with
    private String secretKey;

    private String userAgent = DEFAULT_USER_AGENT;

    private OkHttpClient httpClient = new OkHttpClient();

    /**
     * Creates Minio client object with given endpoint using anonymous access.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient = new MinioClient("https://play.minio.io:9000"); }</pre>
     *
     * @param endpoint  Request endpoint. Endpoint is an URL, domain name, IPv4 or IPv6 address.<pre>
     *              Valid endpoints:
     *              * https://s3.amazonaws.com
     *              * https://s3.amazonaws.com/
     *              * https://play.minio.io:9000
     *              * http://play.minio.io:9010/
     *              * localhost
     *              * localhost.localdomain
     *              * play.minio.io
     *              * 127.0.0.1
     *              * 192.168.1.60
     *              * ::1</pre>
     *
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(String endpoint) throws InvalidEndpointException, InvalidPortException {
        this(endpoint, 0, null, null);
    }

    /**
     * Creates Minio client object with given URL object using anonymous access.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient = new MinioClient(new URL("https://play.minio.io:9000")); }</pre>
     *
     * @param url Endpoint URL object.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(URL url) throws InvalidEndpointException, InvalidPortException {
        this(url.toString(), 0, null, null);
    }

    /**
     * Creates Minio client object with given HttpUrl object using anonymous access.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient = new MinioClient(new HttpUrl.parse("https://play.minio.io:9000")); }</pre>
     *
     * @param url Endpoint HttpUrl object.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(HttpUrl url) throws InvalidEndpointException, InvalidPortException {
        this(url.toString(), 0, null, null);
    }

    /**
     * Creates Minio client object with given endpoint, access key and secret key.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient = new MinioClient("https://play.minio.io:9000", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY"); }</pre>
     *
     * @param endpoint  Request endpoint. Endpoint is an URL, domain name, IPv4 or IPv6 address.<pre>
     *              Valid endpoints:
     *              * https://s3.amazonaws.com
     *              * https://s3.amazonaws.com/
     *              * https://play.minio.io:9000
     *              * http://play.minio.io:9010/
     *              * localhost
     *              * localhost.localdomain
     *              * play.minio.io
     *              * 127.0.0.1
     *              * 192.168.1.60
     *              * ::1</pre>
     * @param accessKey Access key to access service in endpoint.
     * @param secretKey Secret key to access service in endpoint.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(String endpoint, String accessKey, String secretKey)
            throws InvalidEndpointException, InvalidPortException {
        this(endpoint, 0, accessKey, secretKey);
    }

    /**
     * Creates Minio client object with given URL object, access key and secret key.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient = new MinioClient(new URL("https://play.minio.io:9000"), "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY"); }</pre>
     *
     * @param url Endpoint URL object.
     * @param accessKey Access key to access service in endpoint.
     * @param secretKey Secret key to access service in endpoint.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(URL url, String accessKey, String secretKey)
            throws InvalidEndpointException, InvalidPortException {
        this(url.toString(), 0, accessKey, secretKey);
    }

    /**
     * Creates Minio client object with given URL object, access key and secret key.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient = new MinioClient(HttpUrl.parse("https://play.minio.io:9000"), "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY"); }</pre>
     *
     * @param url Endpoint HttpUrl object.
     * @param accessKey Access key to access service in endpoint.
     * @param secretKey Secret key to access service in endpoint.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(HttpUrl url, String accessKey, String secretKey)
            throws InvalidEndpointException, InvalidPortException {
        this(url.toString(), 0, accessKey, secretKey);
    }

    /**
     * Creates Minio client object with given endpoint, port, access key and secret key using secure (HTTPS) connection.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient =
     *                  new MinioClient("play.minio.io", 9000, "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY");
     * }</pre>
     *
     * @param endpoint  Request endpoint. Endpoint is an URL, domain name, IPv4 or IPv6 address.<pre>
     *              Valid endpoints:
     *              * https://s3.amazonaws.com
     *              * https://s3.amazonaws.com/
     *              * https://play.minio.io:9000
     *              * http://play.minio.io:9010/
     *              * localhost
     *              * localhost.localdomain
     *              * play.minio.io
     *              * 127.0.0.1
     *              * 192.168.1.60
     *              * ::1</pre>
     *
     * @param port      Valid port.  It should be in between 1 and 65535.  Unused if endpoint is an URL.
     * @param accessKey Access key to access service in endpoint.
     * @param secretKey Secret key to access service in endpoint.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(String endpoint, int port, String accessKey, String secretKey)
            throws InvalidEndpointException, InvalidPortException {
        this(endpoint, port, accessKey, secretKey, !(endpoint != null && endpoint.startsWith("http://")));
    }

    /**
     * Creates Minio client object with given endpoint, access key and secret key using secure (HTTPS) connection.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient =
     *                      new MinioClient("play.minio.io:9000", "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", true);
     * }</pre>
     *
     * @param endpoint  Request endpoint. Endpoint is an URL, domain name, IPv4 or IPv6 address.<pre>
     *              Valid endpoints:
     *              * https://s3.amazonaws.com
     *              * https://s3.amazonaws.com/
     *              * https://play.minio.io:9000
     *              * http://play.minio.io:9010/
     *              * localhost
     *              * localhost.localdomain
     *              * play.minio.io
     *              * 127.0.0.1
     *              * 192.168.1.60
     *              * ::1</pre>
     *
     * @param accessKey Access key to access service in endpoint.
     * @param secretKey Secret key to access service in endpoint.
     * @param secure If true, access endpoint using HTTPS else access it using HTTP.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
            throws InvalidEndpointException, InvalidPortException {
        this(endpoint, 0, accessKey, secretKey, secure);
    }

    /**
     * Creates Minio client object using given endpoint, port, access key, secret key and secure option.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code MinioClient minioClient =
     *          new MinioClient("play.minio.io", 9000, "YOUR-ACCESSKEYID", "YOUR-SECRETACCESSKEY", false);
     * }</pre>
     *
     * @param endpoint  Request endpoint. Endpoint is an URL, domain name, IPv4 or IPv6 address.<pre>
     *              Valid endpoints:
     *              * https://s3.amazonaws.com
     *              * https://s3.amazonaws.com/
     *              * https://play.minio.io:9000
     *              * http://play.minio.io:9010/
     *              * localhost
     *              * localhost.localdomain
     *              * play.minio.io
     *              * 127.0.0.1
     *              * 192.168.1.60
     *              * ::1</pre>
     *
     * @param port      Valid port.  It should be in between 1 and 65535.  Unused if endpoint is an URL.
     * @param accessKey Access key to access service in endpoint.
     * @param secretKey Secret key to access service in endpoint.
     * @param secure    If true, access endpoint using HTTPS else access it using HTTP.
     *
     * @see #MinioClient(String endpoint)
     * @see #MinioClient(URL url)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey)
     * @see #MinioClient(URL url, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, int port, String accessKey, String secretKey)
     * @see #MinioClient(String endpoint, String accessKey, String secretKey, boolean secure)
     */
    public MinioClient(String endpoint, int port, String accessKey, String secretKey, boolean secure)
            throws InvalidEndpointException, InvalidPortException {
        if (endpoint == null) {
            throw new InvalidEndpointException(NULL_STRING, "null endpoint");
        }

        if (port < 0 || port > 65535) {
            throw new InvalidPortException(port, "port must be in range of 1 to 65535");
        }

        HttpUrl url = HttpUrl.parse(endpoint);
        if (url != null) {
            if (!"/".equals(url.encodedPath())) {
                throw new InvalidEndpointException(endpoint, "no path allowed in endpoint");
            }

            // treat Amazon S3 host as special case
            String amzHost = url.host();
            if (amzHost.endsWith(AMAZONAWS_COM) && !amzHost.equals(S3_AMAZONAWS_COM)) {
                throw new InvalidEndpointException(endpoint,
                        "for Amazon S3, host should be 's3.amazonaws.com' in endpoint");
            }

            HttpUrl.Builder urlBuilder = url.newBuilder();
            Scheme scheme = Scheme.HTTP;
            if (secure) {
                scheme = Scheme.HTTPS;
            }

            urlBuilder.scheme(scheme.toString());

            if (port > 0) {
                urlBuilder.port(port);
            }

            this.baseUrl = urlBuilder.build();
            this.accessKey = accessKey;
            this.secretKey = secretKey;

            return;
        }

        // endpoint may be a valid hostname, IPv4 or IPv6 address
        if (!this.isValidEndpoint(endpoint)) {
            throw new InvalidEndpointException(endpoint, "invalid host");
        }

        // treat Amazon S3 host as special case
        if (endpoint.endsWith(AMAZONAWS_COM) && !endpoint.equals(S3_AMAZONAWS_COM)) {
            throw new InvalidEndpointException(endpoint, "for amazon S3, host should be 's3.amazonaws.com'");
        }

        Scheme scheme = Scheme.HTTP;
        if (secure) {
            scheme = Scheme.HTTPS;
        }

        if (port == 0) {
            this.baseUrl = new HttpUrl.Builder().scheme(scheme.toString()).host(endpoint).build();
        } else {
            this.baseUrl = new HttpUrl.Builder().scheme(scheme.toString()).host(endpoint).port(port).build();
        }
        this.accessKey = accessKey;
        this.secretKey = secretKey;
    }

    /**
     * Returns true if given endpoint is valid else false.
     */
    private boolean isValidEndpoint(String endpoint) {
        if (InetAddressValidator.getInstance().isValid(endpoint)) {
            return true;
        }

        // endpoint may be a hostname
        // refer https://en.wikipedia.org/wiki/Hostname#Restrictions_on_valid_host_names
        // why checks are done like below
        if (endpoint.length() < 1 || endpoint.length() > 253) {
            return false;
        }

        for (String label : endpoint.split("\\.")) {
            if (label.length() < 1 || label.length() > 63) {
                return false;
            }

            if (!(label.matches("^[a-zA-Z0-9][a-zA-Z0-9-]*") && endpoint.matches(".*[a-zA-Z0-9]$"))) {
                return false;
            }
        }

        return true;
    }

    /**
     * Validates if given objectPrefix is valid.
     */
    private void checkObjectPrefix(String prefix) throws InvalidObjectPrefixException {
        // TODO(nl5887): what to do with wildcards in objectPrefix?
        //
        if (prefix.length() > 1024) {
            throw new InvalidObjectPrefixException(prefix, "Object prefix cannot be greater than 1024 characters.");
        }

        try {
            prefix.getBytes("UTF-8");
        } catch (java.io.UnsupportedEncodingException exc) {
            throw new InvalidObjectPrefixException(prefix, "Object prefix cannot be properly encoded to utf-8.");
        }
    }

    /**
     * Validates if given bucket name is DNS compatible.
     */
    private void checkBucketName(String name) throws InvalidBucketNameException {
        if (name == null) {
            throw new InvalidBucketNameException(NULL_STRING, "null bucket name");
        }

        // Bucket names cannot be no less than 3 and no more than 63 characters long.
        if (name.length() < 3 || name.length() > 63) {
            String msg = "bucket name must be at least 3 and no more than 63 characters long";
            throw new InvalidBucketNameException(name, msg);
        }
        // Successive periods in bucket names are not allowed.
        if (name.matches("\\.\\.")) {
            String msg = "bucket name cannot contain successive periods. For more information refer "
                    + "http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html";
            throw new InvalidBucketNameException(name, msg);
        }
        // Bucket names should be dns compatible.
        if (!name.matches("^[a-z0-9][a-z0-9\\.\\-]+[a-z0-9]$")) {
            String msg = "bucket name does not follow Amazon S3 standards. For more information refer "
                    + "http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html";
            throw new InvalidBucketNameException(name, msg);
        }
    }

    /**
     * Sets HTTP connect, write and read timeouts.  A value of 0 means no timeout, otherwise values must be between 1 and
     * Integer.MAX_VALUE when converted to milliseconds.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code minioClient.setTimeout(TimeUnit.SECONDS.toMillis(10), TimeUnit.SECONDS.toMillis(10),
     *                            TimeUnit.SECONDS.toMillis(30)); }</pre>
     *
     * @param connectTimeout    HTTP connect timeout in milliseconds.
     * @param writeTimeout      HTTP write timeout in milliseconds.
     * @param readTimeout       HTTP read timeout in milliseconds.
     */
    public void setTimeout(long connectTimeout, long writeTimeout, long readTimeout) {
        httpClient.setConnectTimeout(connectTimeout, TimeUnit.MILLISECONDS);
        httpClient.setWriteTimeout(writeTimeout, TimeUnit.MILLISECONDS);
        httpClient.setReadTimeout(readTimeout, TimeUnit.MILLISECONDS);
    }

    /**
     * Creates Request object for given request parameters.
     *
     * @param method         HTTP method.
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param region         Amazon S3 region of the bucket.
     * @param headerMap      Map of HTTP headers for the request.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     * @param contentType    Content type of the request body.
     * @param body           HTTP request body.
     * @param length         Length of HTTP request body.
     */
    private Request createRequest(Method method, String bucketName, String objectName, String region,
            Map<String, String> headerMap, Map<String, String> queryParamMap, final String contentType,
            final Object body, final int length)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException {
        if (bucketName == null && objectName != null) {
            throw new InvalidBucketNameException(NULL_STRING, "null bucket name for object '" + objectName + "'");
        }

        HttpUrl.Builder urlBuilder = this.baseUrl.newBuilder();

        if (bucketName != null) {
            checkBucketName(bucketName);

            String host = this.baseUrl.host();
            if (host.equals(S3_AMAZONAWS_COM)) {
                // special case: handle s3.amazonaws.com separately
                if (region != null) {
                    host = AwsS3Endpoints.INSTANCE.endpoint(region);
                }

                boolean usePathStyle = false;
                if (method == Method.PUT && objectName == null && queryParamMap == null) {
                    // use path style for make bucket to workaround "AuthorizationHeaderMalformed" error from s3.amazonaws.com
                    usePathStyle = true;
                } else if (queryParamMap != null && queryParamMap.containsKey("location")) {
                    // use path style for location query
                    usePathStyle = true;
                } else if (bucketName.contains(".") && this.baseUrl.isHttps()) {
                    // use path style where '.' in bucketName causes SSL certificate validation error
                    usePathStyle = true;
                }

                if (usePathStyle) {
                    urlBuilder.host(host);
                    urlBuilder.addPathSegment(bucketName);
                } else {
                    urlBuilder.host(bucketName + "." + host);
                }
            } else {
                urlBuilder.addPathSegment(bucketName);
            }
        }

        if (objectName != null) {
            for (String pathSegment : objectName.split("/")) {
                // Limitation:
                // 1. OkHttp does not allow to add '.' and '..' as path segment.
                // 2. Its not allowed to add path segment as '/', '//', '/usr' or 'usr/'.
                urlBuilder.addPathSegment(pathSegment);
            }
        }

        if (queryParamMap != null) {
            for (Map.Entry<String, String> entry : queryParamMap.entrySet()) {
                urlBuilder.addEncodedQueryParameter(Signer.encodeQueryString(entry.getKey()),
                        Signer.encodeQueryString(entry.getValue()));
            }
        }

        RequestBody requestBody = null;
        if (body != null) {
            requestBody = new RequestBody() {
                @Override
                public MediaType contentType() {
                    if (contentType != null) {
                        return MediaType.parse(contentType);
                    } else {
                        return MediaType.parse("application/octet-stream");
                    }
                }

                @Override
                public long contentLength() {
                    if (body instanceof InputStream || body instanceof RandomAccessFile || body instanceof byte[]) {
                        return length;
                    }

                    if (length == 0) {
                        return -1;
                    } else {
                        return length;
                    }
                }

                @Override
                public void writeTo(BufferedSink sink) throws IOException {
                    byte[] data = null;

                    if (body instanceof InputStream) {
                        InputStream stream = (InputStream) body;
                        sink.write(Okio.source(stream), length);
                    } else if (body instanceof RandomAccessFile) {
                        RandomAccessFile file = (RandomAccessFile) body;
                        sink.write(Okio.source(Channels.newInputStream(file.getChannel())), length);
                    } else if (body instanceof byte[]) {
                        sink.write(data, 0, length);
                    } else {
                        sink.writeUtf8(body.toString());
                    }
                }
            };
        }

        HttpUrl url = urlBuilder.build();
        // urlBuilder does not encode some characters properly for Amazon S3.
        // Encode such characters properly here.
        List<String> pathSegments = url.encodedPathSegments();
        urlBuilder = url.newBuilder();
        for (int i = 0; i < pathSegments.size(); i++) {
            urlBuilder.setEncodedPathSegment(i,
                    pathSegments.get(i).replaceAll("\\!", "%21").replaceAll("\\$", "%24").replaceAll("\\&", "%26")
                            .replaceAll("\\'", "%27").replaceAll("\\(", "%28").replaceAll("\\)", "%29")
                            .replaceAll("\\*", "%2A").replaceAll("\\+", "%2B").replaceAll("\\,", "%2C")
                            .replaceAll("\\:", "%3A").replaceAll("\\;", "%3B").replaceAll("\\=", "%3D")
                            .replaceAll("\\@", "%40").replaceAll("\\[", "%5B").replaceAll("\\]", "%5D"));
        }
        url = urlBuilder.build();

        Request.Builder requestBuilder = new Request.Builder();
        requestBuilder.url(url);
        requestBuilder.method(method.toString(), requestBody);
        if (headerMap != null) {
            for (Map.Entry<String, String> entry : headerMap.entrySet()) {
                requestBuilder.header(entry.getKey(), entry.getValue());
            }
        }

        String sha256Hash = null;
        String md5Hash = null;
        if (this.accessKey != null && this.secretKey != null) {
            // No need to compute sha256 if endpoint scheme is HTTPS. Issue #415.
            if (url.isHttps()) {
                sha256Hash = "UNSIGNED-PAYLOAD";
                if (body instanceof BufferedInputStream) {
                    md5Hash = Digest.md5Hash((BufferedInputStream) body, length);
                } else if (body instanceof RandomAccessFile) {
                    md5Hash = Digest.md5Hash((RandomAccessFile) body, length);
                } else if (body instanceof byte[]) {
                    byte[] data = (byte[]) body;
                    md5Hash = Digest.md5Hash(data, length);
                }
            } else {
                if (body == null) {
                    sha256Hash = Digest.sha256Hash(new byte[0]);
                } else {
                    if (body instanceof BufferedInputStream) {
                        String[] hashes = Digest.sha256md5Hashes((BufferedInputStream) body, length);
                        sha256Hash = hashes[0];
                        md5Hash = hashes[1];
                    } else if (body instanceof RandomAccessFile) {
                        String[] hashes = Digest.sha256md5Hashes((RandomAccessFile) body, length);
                        sha256Hash = hashes[0];
                        md5Hash = hashes[1];
                    } else if (body instanceof byte[]) {
                        byte[] data = (byte[]) body;
                        sha256Hash = Digest.sha256Hash(data, length);
                        md5Hash = Digest.md5Hash(data, length);
                    } else {
                        sha256Hash = Digest.sha256Hash(body.toString());
                    }
                }
            }
        }

        if (md5Hash != null) {
            requestBuilder.header("Content-MD5", md5Hash);
        }
        if (url.port() == 80 || url.port() == 443) {
            requestBuilder.header("Host", url.host());
        } else {
            requestBuilder.header("Host", url.host() + ":" + url.port());
        }
        requestBuilder.header("User-Agent", this.userAgent);
        if (sha256Hash != null) {
            requestBuilder.header("x-amz-content-sha256", sha256Hash);
        }
        DateTime date = new DateTime();
        requestBuilder.header("x-amz-date", date.toString(DateFormat.AMZ_DATE_FORMAT));

        return requestBuilder.build();
    }

    /**
     * Executes given request parameters.
     *
     * @param method         HTTP method.
     * @param region         Amazon S3 region of the bucket.
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param headerMap      Map of HTTP headers for the request.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     * @param contentType    Content type of the request body.
     * @param body           HTTP request body.
     * @param length         Length of HTTP request body.
     */
    private HttpResponse execute(Method method, String region, String bucketName, String objectName,
            Map<String, String> headerMap, Map<String, String> queryParamMap, String contentType, Object body,
            int length) throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException,
            IOException, InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        Request request = createRequest(method, bucketName, objectName, region, headerMap, queryParamMap,
                contentType, body, length);

        if (this.accessKey != null && this.secretKey != null) {
            request = Signer.signV4(request, region, accessKey, secretKey);
        }

        if (this.traceStream != null) {
            this.traceStream.println("---------START-HTTP---------");
            String encodedPath = request.httpUrl().encodedPath();
            String encodedQuery = request.httpUrl().encodedQuery();
            if (encodedQuery != null) {
                encodedPath += "?" + encodedQuery;
            }
            this.traceStream.println(request.method() + " " + encodedPath + " HTTP/1.1");
            String headers = request.headers().toString().replaceAll("Signature=([0-9a-f]+)",
                    "Signature=*REDACTED*");
            this.traceStream.println(headers);
        }

        Response response = this.httpClient.newCall(request).execute();
        if (response == null) {
            if (this.traceStream != null) {
                this.traceStream.println("<NO RESPONSE>");
                this.traceStream.println(END_HTTP);
            }
            throw new NoResponseException();
        }

        if (this.traceStream != null) {
            this.traceStream.println(response.protocol().toString().toUpperCase() + " " + response.code());
            this.traceStream.println(response.headers());
        }

        ResponseHeader header = new ResponseHeader();
        HeaderParser.set(response.headers(), header);

        if (response.isSuccessful()) {
            if (this.traceStream != null) {
                this.traceStream.println(END_HTTP);
            }
            return new HttpResponse(header, response);
        }

        ErrorResponse errorResponse = null;

        // HEAD returns no body, and fails on parseXml
        if (!method.equals(Method.HEAD)) {
            try {
                String errorXml = "";

                // read entire body stream to string.
                Scanner scanner = new java.util.Scanner(response.body().charStream()).useDelimiter("\\A");
                if (scanner.hasNext()) {
                    errorXml = scanner.next();
                }

                errorResponse = new ErrorResponse(new StringReader(errorXml));

                if (this.traceStream != null) {
                    this.traceStream.println(errorXml);
                }
            } finally {
                response.body().close();
            }
        }

        if (this.traceStream != null) {
            this.traceStream.println(END_HTTP);
        }

        if (errorResponse == null) {
            ErrorCode ec;
            switch (response.code()) {
            case 400:
                ec = ErrorCode.INVALID_URI;
                break;
            case 404:
                if (objectName != null) {
                    ec = ErrorCode.NO_SUCH_KEY;
                } else if (bucketName != null) {
                    ec = ErrorCode.NO_SUCH_BUCKET;
                } else {
                    ec = ErrorCode.RESOURCE_NOT_FOUND;
                }
                break;
            case 501:
            case 405:
                ec = ErrorCode.METHOD_NOT_ALLOWED;
                break;
            case 409:
                if (bucketName != null) {
                    ec = ErrorCode.NO_SUCH_BUCKET;
                } else {
                    ec = ErrorCode.RESOURCE_CONFLICT;
                }
                break;
            case 403:
                ec = ErrorCode.ACCESS_DENIED;
                break;
            default:
                throw new InternalException("unhandled HTTP code " + response.code()
                        + ".  Please report this issue at " + "https://github.com/minio/minio-java/issues");
            }

            errorResponse = new ErrorResponse(ec, bucketName, objectName, request.httpUrl().encodedPath(),
                    header.xamzRequestId(), header.xamzId2());
        }

        // invalidate region cache if needed
        if (errorResponse.errorCode() == ErrorCode.NO_SUCH_BUCKET) {
            BucketRegionCache.INSTANCE.remove(bucketName);
            // TODO: handle for other cases as well
            // observation: on HEAD of a bucket with wrong region gives 400 without body
        }

        throw new ErrorResponseException(errorResponse, response);
    }

    /**
     * Updates Region cache for given bucket.
     */
    private void updateRegionCache(String bucketName) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        if (bucketName != null && S3_AMAZONAWS_COM.equals(this.baseUrl.host()) && this.accessKey != null
                && this.secretKey != null && !BucketRegionCache.INSTANCE.exists(bucketName)) {
            Map<String, String> queryParamMap = new HashMap<>();
            queryParamMap.put("location", null);

            HttpResponse response = execute(Method.GET, US_EAST_1, bucketName, null, null, queryParamMap, null,
                    null, 0);

            // existing XmlEntity does not work, so fallback to regular parsing.
            XmlPullParser xpp = xmlPullParserFactory.newPullParser();
            String location = null;

            xpp.setInput(response.body().charStream());
            while (xpp.getEventType() != xpp.END_DOCUMENT) {
                if (xpp.getEventType() == xpp.START_TAG && xpp.getName() == "LocationConstraint") {
                    xpp.next();
                    location = getText(xpp, location);
                    break;
                }
                xpp.next();
            }

            // close response body.
            response.body().close();

            String region;
            if (location == null) {
                region = US_EAST_1;
            } else {
                // eu-west-1 can be sometimes 'EU'.
                if ("EU".equals(location)) {
                    region = "eu-west-1";
                } else {
                    region = location;
                }
            }

            // Add the new location.
            BucketRegionCache.INSTANCE.add(bucketName, region);
        }
    }

    /**
     * Returns text of given XML element.
     */
    private String getText(XmlPullParser xpp, String location) throws XmlPullParserException {
        if (xpp.getEventType() == xpp.TEXT) {
            return xpp.getText();
        }
        return location;
    }

    /**
     * Executes GET method for given request parameters.
     *
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param headerMap      Map of HTTP headers for the request.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     */
    private HttpResponse executeGet(String bucketName, String objectName, Map<String, String> headerMap,
            Map<String, String> queryParamMap) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        updateRegionCache(bucketName);
        return execute(Method.GET, BucketRegionCache.INSTANCE.region(bucketName), bucketName, objectName, headerMap,
                queryParamMap, null, null, 0);
    }

    /**
     * Executes HEAD method for given request parameters.
     *
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     */
    private HttpResponse executeHead(String bucketName, String objectName) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        updateRegionCache(bucketName);
        HttpResponse response = execute(Method.HEAD, BucketRegionCache.INSTANCE.region(bucketName), bucketName,
                objectName, null, null, null, null, 0);
        response.body().close();
        return response;
    }

    /**
     * Executes DELETE method for given request parameters.
     *
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     */
    private HttpResponse executeDelete(String bucketName, String objectName, Map<String, String> queryParamMap)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        updateRegionCache(bucketName);
        HttpResponse response = execute(Method.DELETE, BucketRegionCache.INSTANCE.region(bucketName), bucketName,
                objectName, null, queryParamMap, null, null, 0);
        response.body().close();
        return response;
    }

    /**
     * Executes POST method for given request parameters.
     *
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param headerMap      Map of HTTP headers for the request.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     * @param data           HTTP request body data.
     */
    private HttpResponse executePost(String bucketName, String objectName, Map<String, String> headerMap,
            Map<String, String> queryParamMap, Object data) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        updateRegionCache(bucketName);
        return execute(Method.POST, BucketRegionCache.INSTANCE.region(bucketName), bucketName, objectName,
                headerMap, queryParamMap, null, data, 0);
    }

    /**
     * Executes PUT method for given request parameters.
     *
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param headerMap      Map of HTTP headers for the request.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     * @param region         Amazon S3 region of the bucket.
     * @param data           HTTP request body data.
     * @param length         Length of HTTP request body data.
     */
    private HttpResponse executePut(String bucketName, String objectName, Map<String, String> headerMap,
            Map<String, String> queryParamMap, String region, Object data, int length)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        HttpResponse response = execute(Method.PUT, region, bucketName, objectName, headerMap, queryParamMap, "",
                data, length);
        response.body().close();
        return response;
    }

    /**
     * Executes PUT method for given request parameters.
     *
     * @param bucketName     Bucket name.
     * @param objectName     Object name in the bucket.
     * @param headerMap      Map of HTTP headers for the request.
     * @param queryParamMap  Map of HTTP query parameters of the request.
     * @param data           HTTP request body data.
     * @param length         Length of HTTP request body data.
     */
    private HttpResponse executePut(String bucketName, String objectName, Map<String, String> headerMap,
            Map<String, String> queryParamMap, Object data, int length) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        updateRegionCache(bucketName);
        return executePut(bucketName, objectName, headerMap, queryParamMap,
                BucketRegionCache.INSTANCE.region(bucketName), data, length);
    }

    /**
     * Sets application's name/version to user agent. For more information about user agent
     * refer <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html">#rfc2616</a>.
     *
     * @param name     Your application name.
     * @param version  Your application version.
     */
    @SuppressWarnings("unused")
    public void setAppInfo(String name, String version) {
        if (name == null || version == null) {
            // nothing to do
            return;
        }

        this.userAgent = DEFAULT_USER_AGENT + " " + name.trim() + "/" + version.trim();
    }

    /**
     * Returns meta data information of given object in given bucket.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code ObjectStat objectStat = minioClient.statObject("my-bucketname", "my-objectname");
     * System.out.println(objectStat); }</pre>
     *
     * @param bucketName Bucket name.
     * @param objectName Object name in the bucket.
     *
     * @return Populated object metadata.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     * @see ObjectStat
     */
    public ObjectStat statObject(String bucketName, String objectName) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        HttpResponse response = executeHead(bucketName, objectName);
        ResponseHeader header = response.header();
        return new ObjectStat(bucketName, objectName, header.lastModified(), header.contentLength(), header.etag(),
                header.contentType());
    }

    /**
     * Gets entire object's data as {@link InputStream} in given bucket. The InputStream must be closed
     * after use else the connection will remain open.
     *
     * <p><b>Example:</b>
     * <pre>{@code InputStream stream = minioClient.getObject("my-bucketname", "my-objectname");
     * byte[] buf = new byte[16384];
     * int bytesRead;
     * while ((bytesRead = stream.read(buf, 0, buf.length)) >= 0) {
     *   System.out.println(new String(buf, 0, bytesRead));
     * }
     * stream.close(); }</pre>
     *
     * @param bucketName Bucket name.
     * @param objectName Object name in the bucket.
     *
     * @return {@link InputStream} containing the object data.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public InputStream getObject(String bucketName, String objectName)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException {
        return getObject(bucketName, objectName, 0, null);
    }

    /**
     * Gets object's data starting from given offset as {@link InputStream} in the given bucket. The InputStream must be
     * closed after use else the connection will remain open.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code InputStream stream = minioClient.getObject("my-bucketname", "my-objectname", 1024L);
     * byte[] buf = new byte[16384];
     * int bytesRead;
     * while ((bytesRead = stream.read(buf, 0, buf.length)) >= 0) {
     *   System.out.println(new String(buf, 0, bytesRead));
     * }
     * stream.close(); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name in the bucket.
     * @param offset      Offset to read at.
     *
     * @return {@link InputStream} containing the object's data.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public InputStream getObject(String bucketName, String objectName, long offset)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException {
        return getObject(bucketName, objectName, offset, null);
    }

    /**
     * Gets object's data of given offset and length as {@link InputStream} in the given bucket. The InputStream must be
     * closed after use else the connection will remain open.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code InputStream stream = minioClient.getObject("my-bucketname", "my-objectname", 1024L, 4096L);
     * byte[] buf = new byte[16384];
     * int bytesRead;
     * while ((bytesRead = stream.read(buf, 0, buf.length)) >= 0) {
     *   System.out.println(new String(buf, 0, bytesRead));
     * }
     * stream.close(); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name in the bucket.
     * @param offset      Offset to read at.
     * @param length      Length to read.
     *
     * @return {@link InputStream} containing the object's data.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public InputStream getObject(String bucketName, String objectName, long offset, Long length)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException {
        if (offset < 0) {
            throw new InvalidArgumentException("offset should be zero or greater");
        }

        if (length != null && length <= 0) {
            throw new InvalidArgumentException("length should be greater than zero");
        }

        Map<String, String> headerMap = new HashMap<>();
        if (length != null) {
            headerMap.put("Range", "bytes=" + offset + "-" + (offset + length - 1));
        } else {
            headerMap.put("Range", "bytes=" + offset + "-");
        }

        HttpResponse response = executeGet(bucketName, objectName, headerMap, null);
        return response.body().byteStream();
    }

    /**
     * Gets object's data in the given bucket and stores it to given file name.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code minioClient.getObject("my-bucketname", "my-objectname", "photo.jpg"); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name in the bucket.
     * @param fileName    file name.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void getObject(String bucketName, String objectName, String fileName)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException {
        Path filePath = Paths.get(fileName);
        boolean fileExists = Files.exists(filePath);

        if (fileExists && !Files.isRegularFile(filePath)) {
            throw new InvalidArgumentException(fileName + ": not a regular file");
        }

        ObjectStat objectStat = statObject(bucketName, objectName);
        long length = objectStat.length();
        String etag = objectStat.etag();

        String tempFileName = fileName + "." + etag + ".part.minio";
        Path tempFilePath = Paths.get(tempFileName);
        boolean tempFileExists = Files.exists(tempFilePath);

        if (tempFileExists && !Files.isRegularFile(tempFilePath)) {
            throw new IOException(tempFileName + ": not a regular file");
        }

        long tempFileSize = 0;
        if (tempFileExists) {
            tempFileSize = Files.size(tempFilePath);
            if (tempFileSize > length) {
                Files.delete(tempFilePath);
                tempFileExists = false;
                tempFileSize = 0;
            }
        }

        if (fileExists) {
            long fileSize = Files.size(filePath);
            if (fileSize == length) {
                // already downloaded. nothing to do
                return;
            } else if (fileSize > length) {
                throw new InvalidArgumentException(
                        "'" + fileName + "': object size " + length + " is smaller than file size " + fileSize);
            } else if (!tempFileExists) {
                // before resuming the download, copy filename to tempfilename
                Files.copy(filePath, tempFilePath);
                tempFileSize = fileSize;
                tempFileExists = true;
            }
        }

        InputStream is = null;
        OutputStream os = null;
        try {
            is = getObject(bucketName, objectName, tempFileSize);
            os = Files.newOutputStream(tempFilePath, StandardOpenOption.CREATE, StandardOpenOption.APPEND);
            long bytesWritten = ByteStreams.copy(is, os);
            is.close();
            os.close();

            if (bytesWritten != length - tempFileSize) {
                throw new IOException(tempFileName + ": unexpected data written.  expected = "
                        + (length - tempFileSize) + ", written = " + bytesWritten);
            }

            Files.move(tempFilePath, filePath, StandardCopyOption.REPLACE_EXISTING);
        } finally {
            if (is != null) {
                is.close();
            }
            if (os != null) {
                os.close();
            }
        }
    }

    /**
     * Returns an presigned URL to download the object in the bucket with given expiry time.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code String url = minioClient.presignedGetObject("my-bucketname", "my-objectname", 60 * 60 * 24);
     * System.out.println(url); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name in the bucket.
     * @param expires     Expiration time in seconds of presigned URL.
     *
     * @return string contains URL to download the object.
     *
     * @throws InvalidBucketNameException   upon an invalid bucket name
     * @throws InvalidKeyException          upon an invalid access key or secret key
     * @throws IOException                  upon signature calculation failure
     * @throws NoSuchAlgorithmException     upon requested algorithm was not found during signature calculation
     * @throws InvalidExpiresRangeException upon input expires is out of range
     */
    public String presignedGetObject(String bucketName, String objectName, Integer expires)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidExpiresRangeException {
        // Validate input.
        if (expires < 1 || expires > DEFAULT_EXPIRY_TIME) {
            throw new InvalidExpiresRangeException(expires,
                    "expires must be in range of 1 to " + DEFAULT_EXPIRY_TIME);
        }

        updateRegionCache(bucketName);
        String region = BucketRegionCache.INSTANCE.region(bucketName);

        Request request = createRequest(Method.GET, bucketName, objectName, region, null, null, null, null, 0);
        HttpUrl url = Signer.presignV4(request, region, accessKey, secretKey, expires);
        return url.toString();
    }

    /**
     * Returns an presigned URL to download the object in the bucket with default expiry time.
     * Default expiry time is 7 days in seconds.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code String url = minioClient.presignedGetObject("my-bucketname", "my-objectname");
     * System.out.println(url); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name in the bucket.
     *
     * @return string contains URL to download the object
     *
     * @throws IOException     upon connection error
     * @throws NoSuchAlgorithmException upon requested algorithm was not found during signature calculation
     * @throws InvalidExpiresRangeException upon input expires is out of range
     */
    public String presignedGetObject(String bucketName, String objectName)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidExpiresRangeException {
        return presignedGetObject(bucketName, objectName, DEFAULT_EXPIRY_TIME);
    }

    /**
     * Returns a presigned URL to upload an object in the bucket with given expiry time.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code String url = minioClient.presignedPutObject("my-bucketname", "my-objectname", 60 * 60 * 24);
     * System.out.println(url); }</pre>
     *
     * @param bucketName  Bucket name
     * @param objectName  Object name in the bucket
     * @param expires     Expiration time in seconds to presigned URL.
     *
     * @return string contains URL to upload the object.
     *
     * @throws InvalidBucketNameException   upon an invalid bucket name
     * @throws InvalidKeyException          upon an invalid access key or secret key
     * @throws IOException                  upon signature calculation failure
     * @throws NoSuchAlgorithmException     upon requested algorithm was not found during signature calculation
     * @throws InvalidExpiresRangeException upon input expires is out of range
     */
    public String presignedPutObject(String bucketName, String objectName, Integer expires)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidExpiresRangeException {
        if (expires < 1 || expires > DEFAULT_EXPIRY_TIME) {
            throw new InvalidExpiresRangeException(expires,
                    "expires must be in range of 1 to " + DEFAULT_EXPIRY_TIME);
        }

        updateRegionCache(bucketName);
        String region = BucketRegionCache.INSTANCE.region(bucketName);

        Request request = createRequest(Method.PUT, bucketName, objectName, region, null, null, null, "", 0);
        HttpUrl url = Signer.presignV4(request, region, accessKey, secretKey, expires);
        return url.toString();
    }

    /**
     * Returns a presigned URL to upload an object in the bucket with default expiry time.
     * Default expiry time is 7 days in seconds.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code String url = minioClient.presignedPutObject("my-bucketname", "my-objectname");
     * System.out.println(url); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name in the bucket.
     *
     * @return string contains URL to upload the object.
     *
     * @throws IOException     upon connection error
     * @throws NoSuchAlgorithmException upon requested algorithm was not found during signature calculation
     * @throws InvalidExpiresRangeException upon input expires is out of range
     */
    public String presignedPutObject(String bucketName, String objectName)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidExpiresRangeException {
        return presignedPutObject(bucketName, objectName, DEFAULT_EXPIRY_TIME);
    }

    /**
     * Returns string map for given {@link PostPolicy} to upload object with various post policy conditions.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code // Create new PostPolicy object for 'my-bucketname', 'my-objectname' and 7 days expire time from now.
     * PostPolicy policy = new PostPolicy("my-bucketname", "my-objectname", DateTime.now().plusDays(7));
     * // 'my-objectname' should be 'image/png' content type
     * policy.setContentType("image/png");
     * Map<String,String> formData = minioClient.presignedPostPolicy(policy);
     * // Print a curl command that can be executable with the file /tmp/userpic.png and the file will be uploaded.
     * System.out.print("curl -X POST ");
     * for (Map.Entry<String,String> entry : formData.entrySet()) {
     *   System.out.print(" -F " + entry.getKey() + "=" + entry.getValue());
     * }
     * System.out.println(" -F file=@/tmp/userpic.png https://play.minio.io:9000/my-bucketname"); }</pre>
     *
     * @param policy Post policy of an object.
     * @return Map of strings to construct form-data.
     *
     * @see PostPolicy
     */
    public Map<String, String> presignedPostPolicy(PostPolicy policy) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        updateRegionCache(policy.bucketName());
        return policy.formData(this.accessKey, this.secretKey);
    }

    /**
     * Removes an object from a bucket.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code minioClient.removeObject("my-bucketname", "my-objectname"); }</pre>
     *
     * @param bucketName Bucket name.
     * @param objectName Object name in the bucket.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void removeObject(String bucketName, String objectName) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        executeDelete(bucketName, objectName, null);
    }

    /**
     * Lists object information in given bucket.
     *
     * @param bucketName Bucket name.
     *
     * @return an iterator of Result Items.
     */
    public Iterable<Result<Item>> listObjects(final String bucketName) throws XmlPullParserException {
        return listObjects(bucketName, null);
    }

    /**
     * Lists object information in given bucket and prefix.
     *
     * @param bucketName Bucket name.
     * @param prefix     Prefix string.  List objects whose name starts with `prefix`.
     *
     * @return an iterator of Result Items.
     */
    public Iterable<Result<Item>> listObjects(final String bucketName, final String prefix)
            throws XmlPullParserException {
        // list all objects recursively
        return listObjects(bucketName, prefix, true);
    }

    /**
     * Lists object information as {@code Iterable<Result><Item>>} in given bucket, prefix and recursive flag.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code Iterable<Result<Item>> myObjects = minioClient.listObjects("my-bucketname");
     * for (Result<Item> result : myObjects) {
     *   Item item = result.get();
     *   System.out.println(item.lastModified() + ", " + item.size() + ", " + item.objectName());
     * } }</pre>
     *
     * @param bucketName Bucket name.
     * @param prefix     Prefix string.  List objects whose name starts with `prefix`.
     * @param recursive when false, emulates a directory structure where each listing returned is either a full object
     *                  or part of the object's key up to the first '/'. All objects wit the same prefix up to the first
     *                  '/' will be merged into one entry.
     *
     * @return an iterator of Result Items.
     *
     * @see #listObjects(String bucketName)
     * @see #listObjects(String bucketName, String prefix)
     */
    public Iterable<Result<Item>> listObjects(final String bucketName, final String prefix,
            final boolean recursive) {
        return new Iterable<Result<Item>>() {
            @Override
            public Iterator<Result<Item>> iterator() {
                return new Iterator<Result<Item>>() {
                    private String lastObjectName;
                    private ListBucketResult listBucketResult;
                    private Result<Item> error;
                    private Iterator<Item> itemIterator;
                    private Iterator<Prefix> prefixIterator;
                    private boolean completed = false;

                    private synchronized void populate() {
                        String delimiter = "/";
                        if (recursive) {
                            delimiter = null;
                        }

                        String marker = null;
                        if (this.listBucketResult != null) {
                            if (delimiter != null) {
                                marker = listBucketResult.nextMarker();
                            } else {
                                marker = this.lastObjectName;
                            }
                        }

                        this.listBucketResult = null;
                        this.itemIterator = null;
                        this.prefixIterator = null;

                        try {
                            this.listBucketResult = listObjects(bucketName, marker, prefix, delimiter, null);
                        } catch (InvalidBucketNameException | NoSuchAlgorithmException | InsufficientDataException
                                | IOException | InvalidKeyException | NoResponseException | XmlPullParserException
                                | ErrorResponseException | InternalException e) {
                            this.error = new Result<>(null, e);
                        } finally {
                            if (this.listBucketResult != null) {
                                this.itemIterator = this.listBucketResult.contents().iterator();
                                this.prefixIterator = this.listBucketResult.commonPrefixes().iterator();
                            } else {
                                this.itemIterator = new LinkedList<Item>().iterator();
                                this.prefixIterator = new LinkedList<Prefix>().iterator();
                            }
                        }
                    }

                    @Override
                    public boolean hasNext() {
                        if (this.completed) {
                            return false;
                        }

                        if (this.error == null && this.itemIterator == null && this.prefixIterator == null) {
                            populate();
                        }

                        if (this.error == null && !this.itemIterator.hasNext() && !this.prefixIterator.hasNext()
                                && this.listBucketResult.isTruncated()) {
                            populate();
                        }

                        if (this.error != null) {
                            return true;
                        }

                        if (this.itemIterator.hasNext()) {
                            return true;
                        }

                        if (this.prefixIterator.hasNext()) {
                            return true;
                        }

                        this.completed = true;
                        return false;
                    }

                    @Override
                    public Result<Item> next() {
                        if (this.completed) {
                            throw new NoSuchElementException();
                        }

                        if (this.error == null && this.itemIterator == null && this.prefixIterator == null) {
                            populate();
                        }

                        if (this.error == null && !this.itemIterator.hasNext() && !this.prefixIterator.hasNext()
                                && this.listBucketResult.isTruncated()) {
                            populate();
                        }

                        if (this.error != null) {
                            this.completed = true;
                            return this.error;
                        }

                        if (this.itemIterator.hasNext()) {
                            Item item = this.itemIterator.next();
                            this.lastObjectName = item.objectName();
                            return new Result<>(item, null);
                        }

                        if (this.prefixIterator.hasNext()) {
                            Prefix prefix = this.prefixIterator.next();
                            Item item;
                            try {
                                item = new Item(prefix.prefix(), true);
                            } catch (XmlPullParserException e) {
                                // special case: ignore the error as we can't propagate the exception in next()
                                item = null;
                            }

                            return new Result<>(item, null);
                        }

                        this.completed = true;
                        throw new NoSuchElementException();
                    }

                    @Override
                    public void remove() {
                        throw new UnsupportedOperationException();
                    }
                };
            }
        };
    }

    /**
     * Returns {@link ListBucketResult} of given bucket, marker, prefix, delimiter and maxKeys.
     *
     * @param bucketName Bucket name.
     * @param marker     Marker string.  List objects whose name is greater than `marker`.
     * @param prefix     Prefix string.  List objects whose name starts with `prefix`.
     * @param delimiter  delimiter string.  Group objects whose name contains `delimiter`.
     * @param maxKeys    Maximum number of entries to be returned.
     */
    private ListBucketResult listObjects(String bucketName, String marker, String prefix, String delimiter,
            Integer maxKeys) throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException,
            IOException, InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        Map<String, String> queryParamMap = new HashMap<>();

        if (marker != null) {
            queryParamMap.put("marker", marker);
        }

        if (prefix != null) {
            queryParamMap.put("prefix", prefix);
        }

        if (delimiter != null) {
            queryParamMap.put("delimiter", delimiter);
        }

        if (maxKeys != null) {
            queryParamMap.put("max-keys", maxKeys.toString());
        }

        HttpResponse response = executeGet(bucketName, null, null, queryParamMap);

        ListBucketResult result = new ListBucketResult();
        result.parseXml(response.body().charStream());
        response.body().close();
        return result;
    }

    /**
     * Returns all bucket information owned by the current user.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code List<Bucket> bucketList = minioClient.listBuckets();
     * for (Bucket bucket : bucketList) {
     *   System.out.println(bucket.creationDate() + ", " + bucket.name());
     * } }</pre>
     *
     * @return List of bucket type.
     *
     * @throws NoResponseException     upon no response from server
     * @throws IOException             upon connection error
     * @throws XmlPullParserException  upon parsing response xml
     * @throws ErrorResponseException  upon unsuccessful execution
     * @throws InternalException       upon internal library error
     */
    public List<Bucket> listBuckets() throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        HttpResponse response = executeGet(null, null, null, null);
        ListAllMyBucketsResult result = new ListAllMyBucketsResult();
        result.parseXml(response.body().charStream());
        response.body().close();
        return result.buckets();
    }

    /**
     * Checks if given bucket exist and is having read access.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code boolean found = minioClient.bucketExists("my-bucketname");
     * if (found) {
     *   System.out.println("my-bucketname exists");
     * } else {
     *   System.out.println("my-bucketname does not exist");
     * } }</pre>
     *
     * @param bucketName Bucket name.
     *
     * @return True if the bucket exists and the user has at least read access.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public boolean bucketExists(String bucketName) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        try {
            executeHead(bucketName, null);
            return true;
        } catch (ErrorResponseException e) {
            if (e.errorResponse().errorCode() != ErrorCode.NO_SUCH_BUCKET) {
                throw e;
            }
        }

        return false;
    }

    /**
     * Creates a bucket with default region.
     *
     * @param bucketName Bucket name.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void makeBucket(String bucketName) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        this.makeBucket(bucketName, null);
    }

    /**
     * Creates a bucket with given region.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code minioClient.makeBucket("my-bucketname");
     * System.out.println("my-bucketname is created successfully"); }</pre>
     *
     * @param bucketName Bucket name.
     * @param region     region in which the bucket will be created.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void makeBucket(String bucketName, String region) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        Map<String, String> headerMap = new HashMap<>();

        String configString;
        if (region == null || US_EAST_1.equals(region)) {
            // for 'us-east-1', location constraint is not required.  for more info
            // http://docs.aws.amazon.com/general/latest/gr/rande.html#s3_region
            configString = "";
        } else {
            CreateBucketConfiguration config = new CreateBucketConfiguration(region);
            configString = config.toString();
        }

        executePut(bucketName, null, headerMap, null, US_EAST_1, configString, 0);
    }

    /**
     * Removes a bucket.
     * <p>
     * NOTE: -
     * All objects (including all object versions and delete markers) in the bucket
     * must be deleted prior, this API will not recursively delete objects
     * </p>
     *
     * </p><b>Example:</b><br>
     * <pre>{@code minioClient.removeBucket("my-bucketname");
     * System.out.println("my-bucketname is removed successfully"); }</pre>
     *
     * @param bucketName Bucket name.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void removeBucket(String bucketName) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        executeDelete(bucketName, null, null);
    }

    /**
     * Uploads given file as object in given bucket.
     * <p>
     * If the object is larger than 5MB, the client will automatically use a multipart session.
     * </p>
     * <p>
     * If the session fails, the user may attempt to re-upload the object by attempting to create
     * the exact same object again. The client will examine all parts of any current upload session
     * and attempt to reuse the session automatically. If a mismatch is discovered, the upload will fail
     * before uploading any more data. Otherwise, it will resume uploading where the session left off.
     * </p>
     * <p>
     * If the multipart session fails, the user is responsible for resuming or removing the session.
     * </p>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name to create in the bucket.
     * @param fileName    File name to upload.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void putObject(String bucketName, String objectName, String fileName)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException, InsufficientDataException {
        if (fileName == null || "".equals(fileName)) {
            throw new InvalidArgumentException("empty file name is not allowed");
        }

        Path filePath = Paths.get(fileName);
        if (!Files.isRegularFile(filePath)) {
            throw new InvalidArgumentException("'" + fileName + "': not a regular file");
        }

        String contentType = Files.probeContentType(filePath);
        long size = Files.size(filePath);

        RandomAccessFile file = new RandomAccessFile(filePath.toFile(), "r");
        try {
            putObject(bucketName, objectName, contentType, size, file);
        } finally {
            file.close();
        }
    }

    /**
     * Uploads data from given stream as object to given bucket.
     * <p>
     * If the object is larger than 5MB, the client will automatically use a multipart session.
     * </p>
     * <p>
     * If the session fails, the user may attempt to re-upload the object by attempting to create
     * the exact same object again. The client will examine all parts of any current upload session
     * and attempt to reuse the session automatically. If a mismatch is discovered, the upload will fail
     * before uploading any more data. Otherwise, it will resume uploading where the session left off.
     * </p>
     * <p>
     * If the multipart session fails, the user is responsible for resuming or removing the session.
     * </p>
     *
     * </p><b>Example:</b><br>
     * <pre>{@code StringBuilder builder = new StringBuilder();
     * for (int i = 0; i < 1000; i++) {
     *   builder.append("Sphinx of black quartz, judge my vow: Used by Adobe InDesign to display font samples. ");
     *   builder.append("(29 letters)\n");
     *   builder.append("Jackdaws love my big sphinx of quartz: Similarly, used by Windows XP for some fonts. ");
     *   builder.append("(31 letters)\n");
     *   builder.append("Pack my box with five dozen liquor jugs: According to Wikipedia, this one is used on ");
     *   builder.append("NASAs Space Shuttle. (32 letters)\n");
     *   builder.append("The quick onyx goblin jumps over the lazy dwarf: Flavor text from an Unhinged Magic Card. ");
     *   builder.append("(39 letters)\n");
     *   builder.append("How razorback-jumping frogs can level six piqued gymnasts!: Not going to win any brevity ");
     *   builder.append("awards at 49 letters long, but old-time Mac users may recognize it.\n");
     *   builder.append("Cozy lummox gives smart squid who asks for job pen: A 41-letter tester sentence for Mac ");
     *   builder.append("computers after System 7.\n");
     *   builder.append("A few others we like: Amazingly few discotheques provide jukeboxes; Now fax quiz Jack! my ");
     *   builder.append("brave ghost pled; Watch Jeopardy!, Alex Trebeks fun TV quiz game.\n");
     *   builder.append("---\n");
     * }
     * ByteArrayInputStream bais = new ByteArrayInputStream(builder.toString().getBytes("UTF-8"));
     * // create object
     * minioClient.putObject("my-bucketname", "my-objectname", bais, bais.available(), "application/octet-stream");
     * bais.close();
     * System.out.println("my-bucketname is uploaded successfully"); }</pre>
     *
     * @param bucketName  Bucket name.
     * @param objectName  Object name to create in the bucket.
     * @param stream      stream to upload.
     * @param size        Size of all the data that will be uploaded.
     * @param contentType Content type of the stream.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     *
     * @see #putObject(String bucketName, String objectName, String fileName)
     */
    public void putObject(String bucketName, String objectName, InputStream stream, long size, String contentType)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException, InsufficientDataException {
        putObject(bucketName, objectName, contentType, size, new BufferedInputStream(stream));
    }

    /**
     * Executes put object and returns ETag of the object.
     *
     * @param bucketName   Bucket name.
     * @param objectName   Object name in the bucket.
     * @param length       Length of object data.
     * @param data         Object data.
     * @param uploadId     Upload ID of multipart put object.
     * @param partNumber   Part number of multipart put object.
     */
    private String putObject(String bucketName, String objectName, int length, Object data, String uploadId,
            String contentType, int partNumber) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        Map<String, String> queryParamMap = null;
        if (partNumber > 0 && uploadId != null && !"".equals(uploadId)) {
            queryParamMap = new HashMap<>();
            queryParamMap.put("partNumber", Integer.toString(partNumber));
            queryParamMap.put(UPLOAD_ID, uploadId);
        }
        Map<String, String> headerMap = new HashMap<>();
        if (contentType != null) {
            headerMap.put("Content-Type", contentType);
        } else {
            headerMap.put("Content-Type", "application/octet-stream");
        }
        HttpResponse response = executePut(bucketName, objectName, headerMap, queryParamMap, data, length);
        return response.header().etag();
    }

    /**
     * Executes put object. If size of object data is <= 5MiB, single put object is used else multipart put object is
     * used.  This method also resumes if previous multipart put is found.
     *
     * @param bucketName   Bucket name.
     * @param objectName   Object name in the bucket.
     * @param contentType  Content type of object data.
     * @param size         Size of object data.
     * @param data         Object data.
     */
    private void putObject(String bucketName, String objectName, String contentType, long size, Object data)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException, InvalidArgumentException, InsufficientDataException {
        if (size <= MIN_MULTIPART_SIZE) {
            // Single put object.
            putObject(bucketName, objectName, (int) size, data, null, contentType, 0);
            return;
        }

        /* Multipart upload */

        int[] rv = calculateMultipartSize(size);
        int partSize = rv[0];
        int partCount = rv[1];
        int lastPartSize = rv[2];
        Part[] totalParts = new Part[partCount];

        // check whether there is incomplete multipart upload or not
        String uploadId = getLatestIncompleteUploadId(bucketName, objectName);
        Iterator<Result<Part>> existingParts = null;
        Part part = null;
        if (uploadId != null) {
            // resume previous multipart upload
            existingParts = listObjectParts(bucketName, objectName, uploadId).iterator();
            if (existingParts.hasNext()) {
                part = existingParts.next().get();
            }
        } else {
            // initiate new multipart upload ie no previous multipart found or no previous valid parts for
            // multipart found
            uploadId = initMultipartUpload(bucketName, objectName, contentType);
        }

        int expectedReadSize = partSize;
        for (int partNumber = 1; partNumber <= partCount; partNumber++) {
            if (partNumber == partCount) {
                expectedReadSize = lastPartSize;
            }

            if (part != null && partNumber == part.partNumber() && expectedReadSize == part.partSize()) {
                String md5Hash = Digest.md5Hash(data, expectedReadSize);
                if (md5Hash.equals(part.etag())) {
                    // this part is already uploaded
                    totalParts[partNumber - 1] = new Part(part.partNumber(), part.etag());
                    skipStream(data, expectedReadSize);

                    part = getPart(existingParts);

                    continue;
                }
            }

            String etag = putObject(bucketName, objectName, expectedReadSize, data, uploadId, null, partNumber);
            totalParts[partNumber - 1] = new Part(partNumber, etag);
        }

        completeMultipart(bucketName, objectName, uploadId, totalParts);
    }

    /**
     * Get bucket policy at given objectPrefix
     *
     * @param bucketName   Bucket name.
     * @param objectPrefix name of the object prefix
     *
     * </p><b>Example:</b><br>
     * <pre>{@code String policy = minioClient.getBucketPolicy("my-bucketname", "my-objectname");
     * System.out.println(policy); }</pre>
     */
    public BucketPolicy getBucketPolicy(String bucketName, String objectPrefix)
            throws InvalidBucketNameException, InvalidObjectPrefixException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        checkObjectPrefix(objectPrefix);

        try {
            BucketAccessPolicy policy = getBucketAccessPolicy(bucketName, objectPrefix);
            return policy.identifyPolicyType(bucketName, objectPrefix);
        } catch (ErrorResponseException e) {
            if (e.errorResponse().errorCode() == ErrorCode.NO_SUCH_BUCKET_POLICY) {
                return BucketPolicy.None;
            }
            throw e;
        }
    }

    /**
     * Set policy on bucket and object prefix.
     *
     * @param bucketName   Bucket name.
     * @param objectPrefix name of the object prefix
     * @param bucketPolicy policy can be BucketPolicy.None, BucketPolicy.ReadOnly,
     *                           BucketPolicy.ReadWrite, BucketPolicy.WriteOnly
     *
     * </p><b>Example:</b><br>
     * <pre>{@code setBucketPolicy("my-bucketname", "my-objectname", BucketPolicy.ReadOnly);
     * }</pre>
     */
    public void setBucketPolicy(String bucketName, String objectPrefix, BucketPolicy bucketPolicy)
            throws InvalidBucketNameException, InvalidObjectPrefixException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException, NoSuchBucketPolicyException {
        checkObjectPrefix(objectPrefix);

        BucketAccessPolicy policy = BucketAccessPolicy.none();

        try {
            policy = getBucketAccessPolicy(bucketName, objectPrefix);
        } catch (ErrorResponseException e) {
            if (e.errorResponse().errorCode() != ErrorCode.NO_SUCH_BUCKET_POLICY) {
                throw e;
            }
        }

        if (bucketPolicy.equals(BucketPolicy.None) && !policy.hasStatements()) {
            throw new NoSuchBucketPolicyException(bucketName, objectPrefix, bucketPolicy);
        }

        List<Statement> statements = policy.removeBucketPolicyStatement(bucketName, objectPrefix);

        // add the common bucket statements, if they don't exist
        if (!policy.hasCommonBucketStatement(bucketName)) {
            statements.addAll(BucketAccessPolicy.commonBucketStatement(bucketName));
        }

        List<Statement> generatedStatements = BucketAccessPolicy.generatePolicyStatements(bucketPolicy, bucketName,
                objectPrefix);
        statements.addAll(generatedStatements);

        // prevent request if statements are unchanged
        if (CollectionUtils.isEqualCollection(policy.statements(), statements)) {
            return;
        }

        policy.setStatements(statements);

        // if no statements, remove bucket access policy. Policy with empty statements is invalid.
        if (!policy.hasStatements()) {
            delBucketAccessPolicy(bucketName);
        } else {
            putBucketAccessPolicy(bucketName, policy);
        }
    }

    /**
     * Returns the parsed current bucket access policy.
     */
    private BucketAccessPolicy getBucketAccessPolicy(String bucketName, String objectPrefix)
            throws InvalidBucketNameException, InvalidObjectPrefixException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put("policy", "");

        HttpResponse response = executeGet(bucketName, null, null, queryParamMap);

        BucketAccessPolicy policy = gson.fromJson(response.body().charStream(), BucketAccessPolicy.class);
        response.body().close();

        if (policy == null) {
            throw new com.google.gson.JsonParseException("policy document could not be decoded.");
        }

        return policy;
    }

    /**
     * Deletes the bucket access policy.
     */
    private void delBucketAccessPolicy(String bucketName)
            throws InvalidBucketNameException, InvalidObjectPrefixException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put("policy", "");

        HttpResponse response = executeDelete(bucketName, "", queryParamMap);
        response.body().close();
    }

    /**
     * Sets the bucket access policy.
     */
    private void putBucketAccessPolicy(String bucketName, BucketAccessPolicy policy)
            throws InvalidBucketNameException, InvalidObjectPrefixException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put("policy", "");

        String body = gson.toJson(policy);

        HttpResponse response = executePut(bucketName, "", null, queryParamMap, body, body.length());
        response.body().close();
    }

    /**
     * Returns next part if exists.
     */
    private Part getPart(Iterator<Result<Part>> existingParts) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        Part part;
        part = null;
        if (existingParts.hasNext()) {
            part = existingParts.next().get();
        }
        return part;
    }

    /**
     * Returns latest upload ID of incomplete multipart upload of given bucket name and object name.
     */
    private String getLatestIncompleteUploadId(String bucketName, String objectName)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        Upload latestUpload = null;
        for (Result<Upload> result : listIncompleteUploads(bucketName, objectName, true, false)) {
            Upload upload = result.get();
            if (upload.objectName().equals(objectName)
                    && (latestUpload == null || latestUpload.initiated().compareTo(upload.initiated()) < 0)) {
                latestUpload = upload;
            }
        }

        if (latestUpload != null) {
            return latestUpload.uploadId();
        } else {
            return null;
        }
    }

    /**
     * Lists incomplete uploads of objects in given bucket.
     *
     * @param bucketName Bucket name.
     *
     * @return an iterator of Upload.
     * @see #listIncompleteUploads(String, String, boolean)
     */
    public Iterable<Result<Upload>> listIncompleteUploads(String bucketName) throws XmlPullParserException {
        return listIncompleteUploads(bucketName, null, true, true);
    }

    /**
     * Lists incomplete uploads of objects in given bucket and prefix.
     *
     * @param bucketName Bucket name.
     * @param prefix filters the list of uploads to include only those that start with prefix.
     *
     * @return an iterator of Upload.
     * @see #listIncompleteUploads(String, String, boolean)
     */
    public Iterable<Result<Upload>> listIncompleteUploads(String bucketName, String prefix)
            throws XmlPullParserException {
        return listIncompleteUploads(bucketName, prefix, true, true);
    }

    /**
     * Lists incomplete uploads of objects in given bucket, prefix and recursive flag.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code Iterable<Result<Upload>> myObjects = minioClient.listIncompleteUploads("my-bucketname");
     * for (Result<Upload> result : myObjects) {
     *   Upload upload = result.get();
     *   System.out.println(upload.uploadId() + ", " + upload.objectName());
     * } }</pre>
     *
     * @param bucketName  Bucket name.
     * @param prefix      Prefix string.  List objects whose name starts with `prefix`.
     * @param recursive when false, emulates a directory structure where each listing returned is either a full object
     *                  or part of the object's key up to the first '/'. All uploads with the same prefix up to the first
     *                  '/' will be merged into one entry.
     *
     * @return an iterator of Upload.
     *
     * @see #listIncompleteUploads(String bucketName)
     * @see #listIncompleteUploads(String bucketName, String prefix)
     */
    public Iterable<Result<Upload>> listIncompleteUploads(String bucketName, String prefix, boolean recursive) {
        return listIncompleteUploads(bucketName, prefix, recursive, true);
    }

    /**
     * Returns {@code Iterable<Result<Upload>>} of given bucket name, prefix and recursive flag.
     * All parts size are aggregated when aggregatePartSize is true.
     */
    private Iterable<Result<Upload>> listIncompleteUploads(final String bucketName, final String prefix,
            final boolean recursive, final boolean aggregatePartSize) {
        return new Iterable<Result<Upload>>() {
            @Override
            public Iterator<Result<Upload>> iterator() {
                return new Iterator<Result<Upload>>() {
                    private String nextKeyMarker;
                    private String nextUploadIdMarker;
                    private ListMultipartUploadsResult listMultipartUploadsResult;
                    private Result<Upload> error;
                    private Iterator<Upload> uploadIterator;
                    private boolean completed = false;

                    private synchronized void populate() {
                        String delimiter = "/";
                        if (recursive) {
                            delimiter = null;
                        }

                        this.listMultipartUploadsResult = null;
                        this.uploadIterator = null;

                        try {
                            this.listMultipartUploadsResult = listIncompleteUploads(bucketName, nextKeyMarker,
                                    nextUploadIdMarker, prefix, delimiter, 1000);
                        } catch (InvalidBucketNameException | NoSuchAlgorithmException | InsufficientDataException
                                | IOException | InvalidKeyException | NoResponseException | XmlPullParserException
                                | ErrorResponseException | InternalException e) {
                            this.error = new Result<>(null, e);
                        } finally {
                            if (this.listMultipartUploadsResult != null) {
                                this.uploadIterator = this.listMultipartUploadsResult.uploads().iterator();
                            } else {
                                this.uploadIterator = new LinkedList<Upload>().iterator();
                            }
                        }
                    }

                    private synchronized long getAggregatedPartSize(String objectName, String uploadId)
                            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException,
                            IOException, InvalidKeyException, NoResponseException, XmlPullParserException,
                            ErrorResponseException, InternalException {
                        long aggregatedPartSize = 0;

                        for (Result<Part> result : listObjectParts(bucketName, objectName, uploadId)) {
                            aggregatedPartSize += result.get().partSize();
                        }

                        return aggregatedPartSize;
                    }

                    @Override
                    public boolean hasNext() {
                        if (this.completed) {
                            return false;
                        }

                        if (this.error == null && this.uploadIterator == null) {
                            populate();
                        }

                        if (this.error == null && !this.uploadIterator.hasNext()
                                && this.listMultipartUploadsResult.isTruncated()) {
                            this.nextKeyMarker = this.listMultipartUploadsResult.nextKeyMarker();
                            this.nextUploadIdMarker = this.listMultipartUploadsResult.nextUploadIdMarker();
                            populate();
                        }

                        if (this.error != null) {
                            return true;
                        }

                        if (this.uploadIterator.hasNext()) {
                            return true;
                        }

                        this.completed = true;
                        return false;
                    }

                    @Override
                    public Result<Upload> next() {
                        if (this.completed) {
                            throw new NoSuchElementException();
                        }

                        if (this.error == null && this.uploadIterator == null) {
                            populate();
                        }

                        if (this.error == null && !this.uploadIterator.hasNext()
                                && this.listMultipartUploadsResult.isTruncated()) {
                            this.nextKeyMarker = this.listMultipartUploadsResult.nextKeyMarker();
                            this.nextUploadIdMarker = this.listMultipartUploadsResult.nextUploadIdMarker();
                            populate();
                        }

                        if (this.error != null) {
                            this.completed = true;
                            return this.error;
                        }

                        if (this.uploadIterator.hasNext()) {
                            Upload upload = this.uploadIterator.next();

                            if (aggregatePartSize) {
                                long aggregatedPartSize;

                                try {
                                    aggregatedPartSize = getAggregatedPartSize(upload.objectName(),
                                            upload.uploadId());
                                } catch (InvalidBucketNameException | NoSuchAlgorithmException
                                        | InsufficientDataException | IOException | InvalidKeyException
                                        | NoResponseException | XmlPullParserException | ErrorResponseException
                                        | InternalException e) {
                                    // special case: ignore the error as we can't propagate the exception in next()
                                    aggregatedPartSize = -1;
                                }

                                upload.setAggregatedPartSize(aggregatedPartSize);
                            }

                            return new Result<>(upload, null);
                        }

                        this.completed = true;
                        throw new NoSuchElementException();
                    }

                    @Override
                    public void remove() {
                        throw new UnsupportedOperationException();
                    }
                };
            }
        };
    }

    /**
     * Executes List Incomplete uploads S3 call for given bucket name, key marker, upload id marker, prefix,
     * delimiter and maxUploads and returns {@link ListMultipartUploadsResult}.
     */
    private ListMultipartUploadsResult listIncompleteUploads(String bucketName, String keyMarker,
            String uploadIdMarker, String prefix, String delimiter, int maxUploads)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        if (maxUploads < 0 || maxUploads > 1000) {
            maxUploads = 1000;
        }

        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put("uploads", "");
        queryParamMap.put("max-uploads", Integer.toString(maxUploads));
        queryParamMap.put("prefix", prefix);
        queryParamMap.put("key-marker", keyMarker);
        queryParamMap.put("upload-id-marker", uploadIdMarker);
        queryParamMap.put("delimiter", delimiter);

        HttpResponse response = executeGet(bucketName, null, null, queryParamMap);

        ListMultipartUploadsResult result = new ListMultipartUploadsResult();
        result.parseXml(response.body().charStream());
        response.body().close();
        return result;
    }

    /**
     * Initializes new multipart upload for given bucket name, object name and content type.
     */
    private String initMultipartUpload(String bucketName, String objectName, String contentType)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        Map<String, String> headerMap = new HashMap<>();
        if (contentType != null) {
            headerMap.put("Content-Type", contentType);
        } else {
            headerMap.put("Content-Type", "application/octet-stream");
        }

        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put("uploads", "");

        HttpResponse response = executePost(bucketName, objectName, headerMap, queryParamMap, "");

        InitiateMultipartUploadResult result = new InitiateMultipartUploadResult();
        result.parseXml(response.body().charStream());
        response.body().close();
        return result.uploadId();
    }

    /**
     * Executes complete multipart upload of given bucket name, object name, upload ID and parts.
     */
    private void completeMultipart(String bucketName, String objectName, String uploadId, Part[] parts)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put(UPLOAD_ID, uploadId);

        CompleteMultipartUpload completeManifest = new CompleteMultipartUpload(parts);

        HttpResponse response = executePost(bucketName, objectName, null, queryParamMap, completeManifest);

        // Fixing issue https://github.com/minio/minio-java/issues/391
        String bodyContent = "";
        try {
            // read enitre body stream to string.
            Scanner scanner = new java.util.Scanner(response.body().charStream()).useDelimiter("\\A");
            if (scanner.hasNext()) {
                bodyContent = scanner.next();
            }
        } catch (EOFException e) {
            // Getting EOF exception is not an error.
            // Just log it.
            LOGGER.log(Level.WARNING, "EOF exception occured: " + e);
        } finally {
            response.body().close();
        }

        bodyContent = bodyContent.trim();
        if (!bodyContent.isEmpty()) {
            ErrorResponse errorResponse = new ErrorResponse(new StringReader(bodyContent));
            if (errorResponse.code() != null) {
                throw new ErrorResponseException(errorResponse, response.response());
            }
        }
    }

    /**
     * Executes List object parts of multipart upload for given bucket name, object name and upload ID and
     * returns {@code Iterable<Result<Part>>}.
     */
    private Iterable<Result<Part>> listObjectParts(final String bucketName, final String objectName,
            final String uploadId) {
        return new Iterable<Result<Part>>() {
            @Override
            public Iterator<Result<Part>> iterator() {
                return new Iterator<Result<Part>>() {
                    private int nextPartNumberMarker;
                    private ListPartsResult listPartsResult;
                    private Result<Part> error;
                    private Iterator<Part> partIterator;
                    private boolean completed = false;

                    private synchronized void populate() {
                        this.listPartsResult = null;
                        this.partIterator = null;

                        try {
                            this.listPartsResult = listObjectParts(bucketName, objectName, uploadId,
                                    nextPartNumberMarker);
                        } catch (InvalidBucketNameException | NoSuchAlgorithmException | InsufficientDataException
                                | IOException | InvalidKeyException | NoResponseException | XmlPullParserException
                                | ErrorResponseException | InternalException e) {
                            this.error = new Result<>(null, e);
                        } finally {
                            if (this.listPartsResult != null) {
                                this.partIterator = this.listPartsResult.partList().iterator();
                            } else {
                                this.partIterator = new LinkedList<Part>().iterator();
                            }
                        }
                    }

                    @Override
                    public boolean hasNext() {
                        if (this.completed) {
                            return false;
                        }

                        if (this.error == null && this.partIterator == null) {
                            populate();
                        }

                        if (this.error == null && !this.partIterator.hasNext()
                                && this.listPartsResult.isTruncated()) {
                            this.nextPartNumberMarker = this.listPartsResult.nextPartNumberMarker();
                            populate();
                        }

                        if (this.error != null) {
                            return true;
                        }

                        if (this.partIterator.hasNext()) {
                            return true;
                        }

                        this.completed = true;
                        return false;
                    }

                    @Override
                    public Result<Part> next() {
                        if (this.completed) {
                            throw new NoSuchElementException();
                        }

                        if (this.error == null && this.partIterator == null) {
                            populate();
                        }

                        if (this.error == null && !this.partIterator.hasNext()
                                && this.listPartsResult.isTruncated()) {
                            this.nextPartNumberMarker = this.listPartsResult.nextPartNumberMarker();
                            populate();
                        }

                        if (this.error != null) {
                            this.completed = true;
                            return this.error;
                        }

                        if (this.partIterator.hasNext()) {
                            return new Result<>(this.partIterator.next(), null);
                        }

                        this.completed = true;
                        throw new NoSuchElementException();
                    }

                    @Override
                    public void remove() {
                        throw new UnsupportedOperationException();
                    }
                };
            }
        };
    }

    /**
     * Executes list object parts for given bucket name, object name, upload ID and part number marker and
     * returns {@link ListPartsResult}.
     */
    private ListPartsResult listObjectParts(String bucketName, String objectName, String uploadId,
            int partNumberMarker) throws InvalidBucketNameException, NoSuchAlgorithmException,
            InsufficientDataException, IOException, InvalidKeyException, NoResponseException,
            XmlPullParserException, ErrorResponseException, InternalException {
        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put(UPLOAD_ID, uploadId);
        if (partNumberMarker > 0) {
            queryParamMap.put("part-number-marker", Integer.toString(partNumberMarker));
        }

        HttpResponse response = executeGet(bucketName, objectName, null, queryParamMap);

        ListPartsResult result = new ListPartsResult();
        result.parseXml(response.body().charStream());
        response.body().close();
        return result;
    }

    /**
     * Aborts multipart upload of given bucket name, object name and upload ID.
     */
    private void abortMultipartUpload(String bucketName, String objectName, String uploadId)
            throws InvalidBucketNameException, NoSuchAlgorithmException, InsufficientDataException, IOException,
            InvalidKeyException, NoResponseException, XmlPullParserException, ErrorResponseException,
            InternalException {
        Map<String, String> queryParamMap = new HashMap<>();
        queryParamMap.put(UPLOAD_ID, uploadId);
        executeDelete(bucketName, objectName, queryParamMap);
    }

    /**
     * Removes incomplete multipart upload of given object.
     *
     * </p><b>Example:</b><br>
     * <pre>{@code minioClient.removeIncompleteUpload("my-bucketname", "my-objectname");
     * System.out.println("successfully removed all incomplete upload session of my-bucketname/my-objectname"); }</pre>
     *
     * @param bucketName Bucket name.
     * @param objectName Object name in the bucket.
     *
     * @throws InvalidBucketNameException  upon invalid bucket name is given
     * @throws NoResponseException         upon no response from server
     * @throws IOException                 upon connection error
     * @throws XmlPullParserException      upon parsing response xml
     * @throws ErrorResponseException      upon unsuccessful execution
     * @throws InternalException           upon internal library error
     */
    public void removeIncompleteUpload(String bucketName, String objectName) throws InvalidBucketNameException,
            NoSuchAlgorithmException, InsufficientDataException, IOException, InvalidKeyException,
            NoResponseException, XmlPullParserException, ErrorResponseException, InternalException {
        for (Result<Upload> r : listIncompleteUploads(bucketName, objectName, true, false)) {
            Upload upload = r.get();
            if (objectName.equals(upload.objectName())) {
                abortMultipartUpload(bucketName, objectName, upload.uploadId());
                return;
            }
        }
    }

    /**
     * Skips data of up to given length in given input stream.
     *
     * @param inputStream  Input stream which is intance of {@link RandomAccessFile} or {@link BufferedInputStream}.
     * @param n            Length of bytes to skip.
     */
    private void skipStream(Object inputStream, long n) throws IOException, InsufficientDataException {
        RandomAccessFile file = null;
        BufferedInputStream stream = null;
        if (inputStream instanceof RandomAccessFile) {
            file = (RandomAccessFile) inputStream;
        } else if (inputStream instanceof BufferedInputStream) {
            stream = (BufferedInputStream) inputStream;
        } else {
            throw new IllegalArgumentException("unsupported input stream object");
        }

        if (file != null) {
            file.seek(file.getFilePointer() + n);
            return;
        }

        long bytesSkipped;
        long totalBytesSkipped = 0;

        while ((bytesSkipped = stream.skip(n - totalBytesSkipped)) >= 0) {
            totalBytesSkipped += bytesSkipped;
            if (totalBytesSkipped == n) {
                return;
            }
        }

        throw new InsufficientDataException(
                "Insufficient data.  bytes skipped " + totalBytesSkipped + " expected " + n);
    }

    /**
     * Calculates multipart size of given size and returns three element array contains part size, part count
     * and last part size.
     */
    private static int[] calculateMultipartSize(long size) throws InvalidArgumentException {
        if (size > MAX_OBJECT_SIZE) {
            throw new InvalidArgumentException("size " + size + " is greater than allowed size 5TiB");
        }

        double partSize = Math.ceil((double) size / MAX_MULTIPART_COUNT);
        partSize = Math.ceil(partSize / MIN_MULTIPART_SIZE) * MIN_MULTIPART_SIZE;

        double partCount = Math.ceil(size / partSize);

        double lastPartSize = partSize - (partSize * partCount - size);
        if (lastPartSize == 0.0) {
            lastPartSize = partSize;
        }

        return new int[] { (int) partSize, (int) partCount, (int) lastPartSize };
    }

    /**
     * Enables HTTP call tracing and written to traceStream.
     *
     * @param traceStream {@link OutputStream} for writing HTTP call tracing.
     *
     * @see #traceOff
     */
    public void traceOn(OutputStream traceStream) {
        if (traceStream == null) {
            throw new NullPointerException();
        } else {
            this.traceStream = new PrintWriter(new OutputStreamWriter(traceStream, StandardCharsets.UTF_8), true);
        }
    }

    /**
     * Disables HTTP call tracing previously enabled.
     *
     * @see #traceOn
     */
    public void traceOff() throws IOException {
        this.traceStream = null;
    }
}