com.amazonservices.mws.sellers.MarketplaceWebServiceSellersClient.java Source code

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/******************************************************************************* 
 *  Copyright 2009 Amazon Services.
 *  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://aws.amazon.com/apache2.0
 *  This file 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.
 * ***************************************************************************** 
 * 
 *  Marketplace Web Service Sellers Java Library
 *  API Version: 2011-07-01
 *  Generated: Fri Jun 24 20:08:04 GMT 2011 
 * 
 */

package com.amazonservices.mws.sellers;

import com.amazonservices.mws.sellers.model.*;

import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.HashMap;
import java.util.TreeMap;
import java.util.Iterator;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.TimeZone;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.SignatureException;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import org.apache.commons.codec.binary.Base64;
import org.apache.http.Header;
import org.apache.http.message.BasicHeader;
import org.apache.http.HttpStatus;
import org.apache.http.auth.AuthScope;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.protocol.HTTP;
import org.apache.http.NameValuePair;
import org.apache.http.HttpResponse;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.auth.UsernamePasswordCredentials;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.HttpHost;
import org.apache.http.conn.params.ConnRoutePNames;
import org.apache.http.impl.conn.PoolingClientConnectionManager;
import org.apache.http.client.HttpClient;
import org.apache.http.client.CredentialsProvider;
import org.apache.http.impl.client.BasicCredentialsProvider;
import org.apache.http.protocol.HttpContext;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.client.protocol.ClientContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringReader;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.net.URLEncoder;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Map.Entry;

import javax.xml.transform.stream.StreamSource;

/**
 * This contains the Sellers section of the Marketplace Web Service.
 * 
 * 
 * 
 * MarketplaceWebServiceSellersClient is implementation of
 * MarketplaceWebServiceSellers based on the Apache <a
 * href="http://jakarta.apache.org/commons/httpclient/">HttpClient</a>.
 * 
 */
public class MarketplaceWebServiceSellersClient implements MarketplaceWebServiceSellers {

    private final Log log = LogFactory.getLog(MarketplaceWebServiceSellersClient.class);

    private String awsAccessKeyId = null;
    private String awsSecretAccessKey = null;
    private MarketplaceWebServiceSellersConfig config = null;
    private HttpClient httpClient = null;
    private List<Header> defaultHeaders = new ArrayList<Header>();
    private CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
    private HttpContext httpContext = null;
    private static JAXBContext jaxbContext;
    private static ThreadLocal<Unmarshaller> unmarshaller;
    private static Pattern ERROR_PATTERN_ONE = Pattern.compile(
            ".*\\<RequestId>(.*)\\</RequestId>.*\\<Error>"
                    + "\\<Code>(.*)\\</Code>\\<Message>(.*)\\</Message>\\</Error>.*(\\<Error>)?.*",
            Pattern.MULTILINE | Pattern.DOTALL);
    private static Pattern ERROR_PATTERN_TWO = Pattern.compile(
            ".*\\<Error>\\<Code>(.*)\\</Code>\\<Message>(.*)"
                    + "\\</Message>\\</Error>.*(\\<Error>)?.*\\<RequestID>(.*)\\</RequestID>.*",
            Pattern.MULTILINE | Pattern.DOTALL);
    private static String DEFAULT_ENCODING = "UTF-8";
    /** Initialize JAXBContext and Unmarshaller **/
    static {
        try {
            jaxbContext = JAXBContext.newInstance("com.amazonservices.mws.sellers.model",
                    MarketplaceWebServiceSellers.class.getClassLoader());
        } catch (JAXBException ex) {
            throw new ExceptionInInitializerError(ex);
        }
        unmarshaller = new ThreadLocal<Unmarshaller>() {
            @Override
            protected synchronized Unmarshaller initialValue() {
                try {
                    return jaxbContext.createUnmarshaller();
                } catch (JAXBException e) {
                    throw new ExceptionInInitializerError(e);
                }
            }
        };
    }

    /**
     * Constructs MarketplaceWebServiceSellersClient with AWS Access Key ID and
     * AWS Secret Key
     * 
     * @param awsAccessKeyId
     *            AWS Access Key ID
     * @param awsSecretAccessKey
     *            AWS Secret Access Key
     */
    public MarketplaceWebServiceSellersClient(String awsAccessKeyId, String awsSecretAccessKey,
            String applicationName, String applicationVersion) {
        this(awsAccessKeyId, awsSecretAccessKey, applicationName, applicationVersion,
                new MarketplaceWebServiceSellersConfig());
    }

    /**
     * Constructs MarketplaceWebServiceSellersClient with AWS Access Key ID, AWS
     * Secret Key and MarketplaceWebServiceSellersConfig. Use
     * MarketplaceWebServiceSellersConfig to pass additional configuration that
     * affects how service is being called.
     * 
     * @param awsAccessKeyId
     *            AWS Access Key ID
     * @param awsSecretAccessKey
     *            AWS Secret Access Key
     * @param config
     *            Additional configuration options
     */
    public MarketplaceWebServiceSellersClient(String awsAccessKeyId, String awsSecretAccessKey,
            String applicationName, String applicationVersion, MarketplaceWebServiceSellersConfig config) {
        this.awsAccessKeyId = awsAccessKeyId;
        this.awsSecretAccessKey = awsSecretAccessKey;
        this.config = config;
        this.httpClient = configureHttpClient(applicationName, applicationVersion);

    }

    /**
     * Remove all leading whitespace, trailing whitespace, repeated whitespace
     * and replace any interior whitespace with a single space
     */
    private static String clean(String s) {
        return s.replaceAll("\\s", " ").replaceAll(" {2,}", " ").trim();
    }

    public static String quoteAppName(String s) {
        return clean(s).replace("\\", "\\\\").replace("/", "\\/");
    }

    public static String quoteAppVersion(String s) {
        return clean(s).replace("\\", "\\\\").replace("(", "\\(");
    }

    public static String quoteAttributeName(String s) {
        return clean(s).replace("\\", "\\\\").replace("=", "\\=");
    }

    public static String quoteAttributeValue(String s) {
        return clean(s).replace("\\", "\\\\").replace(";", "\\;").replace(")", "\\)");
    }

    private static final String clientVersion = "2012-09-28";

    // Public API ------------------------------------------------------------//

    /**
     * List Marketplace Participations
     * 
     * This operation can be used to list all Marketplaces that a seller can
     * sell in. The operation returns a List of Participation elements and a
     * List of Marketplace elements. The SellerId is the only parameter required
     * by this operation.
     * 
     * @param request
     *            ListMarketplaceParticipationsRequest request
     * @return ListMarketplaceParticipations Response from the service
     * 
     * @throws MarketplaceWebServiceSellersException
     */
    public ListMarketplaceParticipationsResponse listMarketplaceParticipations(
            ListMarketplaceParticipationsRequest request) throws MarketplaceWebServiceSellersException {
        return invoke(ListMarketplaceParticipationsResponse.class, convertListMarketplaceParticipations(request));
    }

    /**
     * List Marketplace Participations By Next Token
     * 
     * If ListMarketplaces cannot return all the marketplaces in one go, it will
     * provide a nextToken. That nextToken can be used with this operation to
     * retrieve the next batch of Marketplaces for that SellerId.
     * 
     * @param request
     *            ListMarketplaceParticipationsByNextTokenRequest request
     * @return ListMarketplaceParticipationsByNextToken Response from the
     *         service
     * 
     * @throws MarketplaceWebServiceSellersException
     */
    public ListMarketplaceParticipationsByNextTokenResponse listMarketplaceParticipationsByNextToken(
            ListMarketplaceParticipationsByNextTokenRequest request) throws MarketplaceWebServiceSellersException {
        return invoke(ListMarketplaceParticipationsByNextTokenResponse.class,
                convertListMarketplaceParticipationsByNextToken(request));
    }

    /**
     * Get Service Status
     * 
     * Returns the service status of a particular MWS API section. The operation
     * takes no input. All API sections within the API are required to implement
     * this operation.
     * 
     * @param request
     *            GetServiceStatusRequest request
     * @return GetServiceStatus Response from the service
     * 
     * @throws MarketplaceWebServiceSellersException
     */
    public GetServiceStatusResponse getServiceStatus(GetServiceStatusRequest request)
            throws MarketplaceWebServiceSellersException {
        return invoke(GetServiceStatusResponse.class, convertGetServiceStatus(request));
    }

    // Private API
    // ------------------------------------------------------------//

    /**
     * Configure HttpClient with set of defaults as well as configuration from
     * MarketplaceWebServiceSellersConfig instance
     * 
     */
    private HttpClient configureHttpClient(String applicationName, String applicationVersion) {

        // respect a user-provided User-Agent header as-is, but if none is provided
        // then generate one satisfying the MWS User-Agent requirements
        if (config.getUserAgent() == null) {
            config.setUserAgent(quoteAppName(applicationName), quoteAppVersion(applicationVersion),
                    quoteAttributeValue("Java/" + System.getProperty("java.version") + "/"
                            + System.getProperty("java.class.version") + "/" + System.getProperty("java.vendor")),

                    quoteAttributeName("Platform"),
                    quoteAttributeValue("" + System.getProperty("os.name") + "/" + System.getProperty("os.arch")
                            + "/" + System.getProperty("os.version")),

                    quoteAttributeName("MWSClientVersion"), quoteAttributeValue(clientVersion));
        }

        defaultHeaders.add(new BasicHeader("X-Amazon-User-Agent", config.getUserAgent()));

        /* Set http client parameters */
        BasicHttpParams httpParams = new BasicHttpParams();

        httpParams.setParameter(CoreProtocolPNames.USER_AGENT, config.getUserAgent());

        /* Set connection parameters */
        HttpConnectionParams.setConnectionTimeout(httpParams, 50000);
        HttpConnectionParams.setSoTimeout(httpParams, 50000);
        HttpConnectionParams.setStaleCheckingEnabled(httpParams, true);
        HttpConnectionParams.setTcpNoDelay(httpParams, true);

        /* Set connection manager */
        PoolingClientConnectionManager connectionManager = new PoolingClientConnectionManager();
        connectionManager.setMaxTotal(config.getMaxConnections());
        connectionManager.setDefaultMaxPerRoute(config.getMaxConnections());

        /* Set http client */
        httpClient = new DefaultHttpClient(connectionManager, httpParams);
        httpContext = new BasicHttpContext();

        /* Set proxy if configured */
        if (config.isSetProxyHost() && config.isSetProxyPort()) {
            log.info("Configuring Proxy. Proxy Host: " + config.getProxyHost() + "Proxy Port: "
                    + config.getProxyPort());
            final HttpHost hostConfiguration = new HttpHost(config.getProxyHost(), config.getProxyPort(),
                    (usesHttps(config.getServiceURL()) ? "https" : "http"));
            httpContext = new BasicHttpContext();
            httpClient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, hostConfiguration);

            if (config.isSetProxyUsername() && config.isSetProxyPassword()) {
                credentialsProvider.setCredentials(new AuthScope(config.getProxyHost(), config.getProxyPort()),
                        new UsernamePasswordCredentials(config.getProxyUsername(), config.getProxyPassword()));
                httpContext.setAttribute(ClientContext.CREDS_PROVIDER, credentialsProvider);

            }

        }

        return httpClient;
    }

    /**
     * Invokes request using parameters from parameters map. Returns response of
     * the T type passed to this method
     */

    private <T> T invoke(Class<T> clazz, Map<String, String> parameters)
            throws MarketplaceWebServiceSellersException {

        String actionName = parameters.get("Action");
        T response = null;
        String responseBodyString = null;
        HttpPost method = new HttpPost(config.getServiceURL());
        int status = -1;

        log.debug("Invoking" + actionName + " request. Current parameters: " + parameters);

        try {

            /* Set content type and encoding */
            log.debug("Setting content-type to application/x-www-form-urlencoded; charset="
                    + DEFAULT_ENCODING.toLowerCase());
            method.addHeader("Content-Type",
                    "application/x-www-form-urlencoded; charset=" + DEFAULT_ENCODING.toLowerCase());
            /* Set X-Amazon-User-Agent to header */
            method.addHeader("X-Amazon-User-Agent", config.getUserAgent());

            /* Add required request parameters and set request body */
            log.debug("Adding required parameters...");
            addRequiredParametersToRequest(method, parameters);
            log.debug("Done adding additional required parameteres. Parameters now: " + parameters);

            boolean shouldRetry = true;
            int retries = 0;
            do {
                log.debug("Sending Request to host:  " + config.getServiceURL());

                try {

                    /* Submit request */
                    HttpResponse postResponse;
                    postResponse = httpClient.execute(method, httpContext);
                    status = postResponse.getStatusLine().getStatusCode();

                    /* Consume response stream */
                    responseBodyString = getResponsBodyAsString(postResponse.getEntity().getContent());

                    /*
                     * Successful response. Attempting to unmarshal into the
                     * <Action>Response type
                     */
                    if (status == HttpStatus.SC_OK && responseBodyString != null) {
                        shouldRetry = false;
                        log.debug("Received Response. Status: " + status + ". " + "Response Body: "
                                + responseBodyString);
                        log.debug("Attempting to unmarshal into the " + actionName + "Response type...");
                        response = clazz.cast(getUnmarshaller()
                                .unmarshal(new StreamSource(new StringReader(responseBodyString))));

                        log.debug("Unmarshalled response into " + actionName + "Response type.");

                    } else { /*
                             * Unsucessful response. Attempting to unmarshall
                             * into ErrorResponse type
                             */

                        log.debug("Received Response. Status: " + status + ". " + "Response Body: "
                                + responseBodyString);

                        if ((status == HttpStatus.SC_INTERNAL_SERVER_ERROR && pauseIfRetryNeeded(++retries))) {
                            shouldRetry = true;
                        } else {
                            log.debug("Attempting to unmarshal into the ErrorResponse type...");
                            ErrorResponse errorResponse = (ErrorResponse) getUnmarshaller()
                                    .unmarshal(new StreamSource(new StringReader(responseBodyString)));

                            log.debug("Unmarshalled response into the ErrorResponse type.");

                            com.amazonservices.mws.sellers.model.Error error = errorResponse.getError().get(0);
                            if (status == HttpStatus.SC_SERVICE_UNAVAILABLE
                                    && !(error.getCode().equals("RequestThrottled"))
                                    && pauseIfRetryNeeded(++retries)) {
                                shouldRetry = true;
                            } else {
                                shouldRetry = false;
                                throw new MarketplaceWebServiceSellersException(error.getMessage(), status,
                                        error.getCode(), error.getType(), errorResponse.getRequestId(),
                                        errorResponse.toXML());
                            }
                        }
                    }
                } catch (JAXBException je) {
                    /*
                     * Response cannot be unmarshalled neither as
                     * <Action>Response or ErrorResponse types. Checking for
                     * other possible errors.
                     */

                    log.debug("Caught JAXBException", je);
                    log.debug("Response cannot be unmarshalled neither as " + actionName
                            + "Response or ErrorResponse types." + "Checking for other possible errors.");

                    MarketplaceWebServiceSellersException awse = processErrors(responseBodyString, status);

                    throw awse;

                } catch (IOException ioe) {
                    log.debug("Caught IOException exception", ioe);
                    throw new MarketplaceWebServiceSellersException("Internal Error", ioe);
                } catch (MarketplaceWebServiceSellersException e) {
                    throw e;
                } catch (Exception e) {
                    log.debug("Caught Exception", e);
                    throw new MarketplaceWebServiceSellersException(e);
                } finally {
                    method.releaseConnection();
                }
            } while (shouldRetry);

        } catch (MarketplaceWebServiceSellersException se) {
            log.debug("Caught MarketplaceWebServiceSellersException", se);
            throw se;

        } catch (Throwable t) {
            log.debug("Caught Exception", t);
            throw new MarketplaceWebServiceSellersException(t);
        }
        return response;
    }

    /**
     * Read stream into string
     * 
     * @param input
     *            stream to read
     */
    private String getResponsBodyAsString(InputStream input) throws IOException {
        String responsBodyString = null;
        try {
            Reader reader = new InputStreamReader(input, DEFAULT_ENCODING);
            StringBuilder b = new StringBuilder();
            char[] c = new char[1024];
            int len;
            while (0 < (len = reader.read(c))) {
                b.append(c, 0, len);
            }
            responsBodyString = b.toString();
        } finally {
            input.close();
        }
        return responsBodyString;
    }

    /**
     * Exponential sleep on failed request. Sleeps and returns true if retry
     * needed
     * 
     * @param retries
     *            current retry
     * @throws java.lang.InterruptedException
     */
    private boolean pauseIfRetryNeeded(int retries) throws InterruptedException {
        if (retries <= config.getMaxErrorRetry()) {
            long delay = (long) (Math.pow(4, retries) * 100L);
            log.debug("Retriable error detected, will retry in " + delay + "ms, attempt numer: " + retries);
            Thread.sleep(delay);
            return true;
        } else {
            return false;
        }
    }

    /**
     * Add authentication related and version parameter and set request body
     * with all of the parameters
     * @throws UnsupportedEncodingException 
     */
    private void addRequiredParametersToRequest(HttpPost method, Map<String, String> parameters)
            throws SignatureException, UnsupportedEncodingException {
        parameters.put("Version", config.getServiceVersion());
        parameters.put("SignatureVersion", config.getSignatureVersion());
        parameters.put("Timestamp", getFormattedTimestamp());
        parameters.put("AWSAccessKeyId", this.awsAccessKeyId);
        parameters.put("Signature", signParameters(parameters, this.awsSecretAccessKey));
        List<NameValuePair> parameterList = new ArrayList<NameValuePair>();
        for (Entry<String, String> entry : parameters.entrySet()) {
            String key = entry.getKey() == null ? "" : entry.getKey();
            String value = entry.getValue() == null ? "" : entry.getValue();
            parameterList.add(new BasicNameValuePair(key, value));
        }
        method.setEntity(new UrlEncodedFormEntity(parameterList, HTTP.UTF_8));

    }

    private MarketplaceWebServiceSellersException processErrors(String responseString, int status) {
        MarketplaceWebServiceSellersException ex = null;
        Matcher matcher = null;
        if (responseString != null && responseString.startsWith("<")) {
            matcher = ERROR_PATTERN_ONE.matcher(responseString);
            if (matcher.matches()) {
                ex = new MarketplaceWebServiceSellersException(matcher.group(3), status, matcher.group(2),
                        "Unknown", matcher.group(1), responseString);
            } else {
                matcher = ERROR_PATTERN_TWO.matcher(responseString);
                if (matcher.matches()) {
                    ex = new MarketplaceWebServiceSellersException(matcher.group(2), status, matcher.group(1),
                            "Unknown", matcher.group(4), responseString);
                } else {
                    ex = new MarketplaceWebServiceSellersException("Internal Error", status);
                    log.debug("Service Error. Response Status: " + status);
                }
            }
        } else {
            ex = new MarketplaceWebServiceSellersException("Internal Error", status);
            log.debug("Service Error. Response Status: " + status);
        }
        return ex;
    }

    /**
     * Formats date as ISO 8601 timestamp
     */
    private String getFormattedTimestamp() {
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        df.setTimeZone(TimeZone.getTimeZone("UTC"));
        return df.format(new Date());
    }

    /**
     * Computes RFC 2104-compliant HMAC signature for request parameters
     * Implements AWS Signature, as per following spec:
     * 
     * If Signature Version is 0, it signs concatenated Action and Timestamp
     * 
     * If Signature Version is 1, it performs the following:
     * 
     * Sorts all parameters (including SignatureVersion and excluding Signature,
     * the value of which is being created), ignoring case.
     * 
     * Iterate over the sorted list and append the parameter name (in original
     * case) and then its value. It will not URL-encode the parameter values
     * before constructing this string. There are no separators.
     * 
     * If Signature Version is 2, string to sign is based on following:
     * 
     * 1. The HTTP Request Method followed by an ASCII newline (%0A) 2. The HTTP
     * Host header in the form of lowercase host, followed by an ASCII newline.
     * 3. The URL encoded HTTP absolute path component of the URI (up to but not
     * including the query string parameters); if this is empty use a forward
     * '/'. This parameter is followed by an ASCII newline. 4. The concatenation
     * of all query string components (names and values) as UTF-8 characters
     * which are URL encoded as per RFC 3986 (hex characters MUST be uppercase),
     * sorted using lexicographic byte ordering. Parameter names are separated
     * from their values by the '=' character (ASCII character 61), even if the
     * value is empty. Pairs of parameter and values are separated by the '&'
     * character (ASCII code 38).
     * 
     */
    private String signParameters(Map<String, String> parameters, String key) throws SignatureException {

        String signatureVersion = parameters.get("SignatureVersion");
        String algorithm = "HmacSHA1";
        String stringToSign = null;
        if ("0".equals(signatureVersion)) {
            stringToSign = calculateStringToSignV0(parameters);
        } else if ("1".equals(signatureVersion)) {
            stringToSign = calculateStringToSignV1(parameters);
        } else if ("2".equals(signatureVersion)) {
            algorithm = config.getSignatureMethod();
            parameters.put("SignatureMethod", algorithm);
            stringToSign = calculateStringToSignV2(parameters);
        } else {
            throw new SignatureException("Invalid Signature Version specified");
        }
        log.debug("Calculated string to sign: " + stringToSign);
        return sign(stringToSign, key, algorithm);
    }

    /**
     * Calculate String to Sign for SignatureVersion 0
     * 
     * @param parameters
     *            request parameters
     * @return String to Sign
     * @throws java.security.SignatureException
     */
    private String calculateStringToSignV0(Map<String, String> parameters) {
        StringBuilder data = new StringBuilder();
        data.append(parameters.get("Action")).append(parameters.get("Timestamp"));
        return data.toString();
    }

    /**
     * Calculate String to Sign for SignatureVersion 1
     * 
     * @param parameters
     *            request parameters
     * @return String to Sign
     * @throws java.security.SignatureException
     */
    @SuppressWarnings("rawtypes")
    private String calculateStringToSignV1(Map<String, String> parameters) {
        StringBuilder data = new StringBuilder();
        Map<String, String> sorted = new TreeMap<String, String>(String.CASE_INSENSITIVE_ORDER);
        sorted.putAll(parameters);
        Iterator pairs = sorted.entrySet().iterator();
        while (pairs.hasNext()) {
            Map.Entry pair = (Map.Entry) pairs.next();
            data.append(pair.getKey());
            data.append(pair.getValue());
        }
        return data.toString();
    }

    /**
     * Calculate String to Sign for SignatureVersion 2
     * 
     * @param parameters
     *            request parameters
     * @return String to Sign
     * @throws java.security.SignatureException
     */
    private String calculateStringToSignV2(Map<String, String> parameters) throws SignatureException {
        StringBuilder data = new StringBuilder();
        data.append("POST");
        data.append("\n");
        URI endpoint = null;
        try {
            endpoint = new URI(config.getServiceURL().toLowerCase());
        } catch (URISyntaxException ex) {
            log.debug("URI Syntax Exception", ex);
            throw new SignatureException("URI Syntax Exception thrown " + "while constructing string to sign", ex);
        }
        data.append(endpoint.getHost());
        if (!usesAStandardPort(config.getServiceURL())) {
            data.append(":");
            data.append(endpoint.getPort());
        }
        data.append("\n");
        String uri = "/Sellers/2011-07-01";
        data.append(urlEncode(uri, true));
        data.append("\n");
        Map<String, String> sorted = new TreeMap<String, String>();
        sorted.putAll(parameters);
        Iterator<Map.Entry<String, String>> pairs = sorted.entrySet().iterator();
        while (pairs.hasNext()) {
            Map.Entry<String, String> pair = pairs.next();
            String key = pair.getKey();
            data.append(urlEncode(key, false));
            data.append("=");
            String value = pair.getValue();
            data.append(urlEncode(value, false));
            if (pairs.hasNext()) {
                data.append("&");
            }
        }
        return data.toString();
    }

    private String urlEncode(String value, boolean path) {
        String encoded = null;
        try {
            encoded = URLEncoder.encode(value, DEFAULT_ENCODING).replace("+", "%20").replace("*", "%2A")
                    .replace("%7E", "~");
            if (path) {
                encoded = encoded.replace("%2F", "/");
            }
        } catch (UnsupportedEncodingException ex) {
            log.debug("Unsupported Encoding Exception", ex);
            throw new RuntimeException(ex);
        }
        return encoded;
    }

    /**
     * Computes RFC 2104-compliant HMAC signature.
     * 
     */
    private String sign(String data, String key, String algorithm) throws SignatureException {
        byte[] signature;
        try {
            Mac mac = Mac.getInstance(algorithm);
            mac.init(new SecretKeySpec(key.getBytes(), algorithm));
            signature = Base64.encodeBase64(mac.doFinal(data.getBytes(DEFAULT_ENCODING)));
        } catch (Exception e) {
            throw new SignatureException("Failed to generate signature: " + e.getMessage(), e);
        }

        return new String(signature);
    }

    /**
     * Get unmarshaller for current thread
     */
    private Unmarshaller getUnmarshaller() {
        return unmarshaller.get();
    }

    /**
     * Convert ListMarketplaceParticipationsRequest to name value pairs
     */
    private Map<String, String> convertListMarketplaceParticipations(ListMarketplaceParticipationsRequest request) {

        Map<String, String> params = new HashMap<String, String>();
        params.put("Action", "ListMarketplaceParticipations");
        if (request.isSetSellerId()) {
            params.put("SellerId", request.getSellerId());
        }

        return params;
    }

    /**
     * Convert ListMarketplaceParticipationsByNextTokenRequest to name value
     * pairs
     */
    private Map<String, String> convertListMarketplaceParticipationsByNextToken(
            ListMarketplaceParticipationsByNextTokenRequest request) {

        Map<String, String> params = new HashMap<String, String>();
        params.put("Action", "ListMarketplaceParticipationsByNextToken");
        if (request.isSetSellerId()) {
            params.put("SellerId", request.getSellerId());
        }
        if (request.isSetNextToken()) {
            params.put("NextToken", request.getNextToken());
        }

        return params;
    }

    /**
     * Convert GetServiceStatusRequest to name value pairs
     */
    private Map<String, String> convertGetServiceStatus(GetServiceStatusRequest request) {

        Map<String, String> params = new HashMap<String, String>();
        params.put("Action", "GetServiceStatus");
        if (request.isSetSellerId()) {
            params.put("SellerId", request.getSellerId());
        }

        return params;
    }

    private static boolean usesHttps(String url) {
        URL urlToCheck;
        try {
            urlToCheck = new URL(url);
        } catch (MalformedURLException e) {
            return false;
        }
        if (urlToCheck.getProtocol().equals("https")) {
            return true;
        } else {
            return false;
        }
    }

    private static int extractPortNumber(String url, boolean usesHttps) {
        URL urlToCheck;
        try {
            urlToCheck = new URL(url);
        } catch (MalformedURLException e) {
            throw new RuntimeException("not a URL", e);
        }

        int portNumber = urlToCheck.getPort();
        if (portNumber == -1) {
            // no port was specified
            if (usesHttps) {
                // it uses https, so we should return the standard https port number
                return 443;
            } else {
                // it uses http, so we should return the standard http port number
                return 80;
            }
        } else {
            return portNumber;
        }
    }

    private static boolean usesAStandardPort(String url) {
        boolean usesHttps = usesHttps(url);
        int portNumber = extractPortNumber(url, usesHttps);
        return usesHttps && portNumber == 443 || !usesHttps && portNumber == 80;
    }

    @SuppressWarnings("unused")
    private String urlEncode(String rawValue) {
        return urlEncode(rawValue, false);
    }

}