org.apache.wicket.util.io.Streams.java Source code

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Here is the source code for org.apache.wicket.util.io.Streams.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.wicket.util.io;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.Reader;
import java.net.URL;
import java.net.URLConnection;
import java.util.Properties;

import org.apache.wicket.util.lang.Args;

/**
 * Utilities methods for working with input and output streams.
 * 
 * @author Jonathan Locke
 * @author Igor Vaynberg
 */
public final class Streams {
    /**
     * Writes the input stream to the output stream. Input is done without a Reader object, meaning
     * that the input is copied in its raw form. After it is copied it will close the streams.
     * 
     * @param in
     *            The input stream
     * @param out
     *            The output stream
     * @return Number of bytes copied from one stream to the other
     * @throws IOException
     */
    public static int copyAndClose(final InputStream in, final OutputStream out) throws IOException {
        try {
            return copy(in, out);
        } finally {
            IOUtils.closeQuietly(in);
            IOUtils.closeQuietly(out);
        }
    }

    /**
     * Writes the input stream to the output stream. Input is done without a Reader object, meaning
     * that the input is copied in its raw form.
     * 
     * @param in
     *            The input stream
     * @param out
     *            The output stream
     * @return Number of bytes copied from one stream to the other
     * @throws IOException
     */
    public static int copy(final InputStream in, final OutputStream out) throws IOException {
        return copy(in, out, 4096);
    }

    /**
     * Writes the input stream to the output stream. Input is done without a Reader object, meaning
     * that the input is copied in its raw form.
     * 
     * @param in
     *            The input stream
     * @param out
     *            The output stream
     * @param bufSize
     *            The buffer size. A good value is 4096.
     * @return Number of bytes copied from one stream to the other
     * @throws IOException
     */
    public static int copy(final InputStream in, final OutputStream out, final int bufSize) throws IOException {
        if (bufSize <= 0) {
            throw new IllegalArgumentException("The parameter 'bufSize' must not be <= 0");
        }

        final byte[] buffer = new byte[bufSize];
        int bytesCopied = 0;
        while (true) {
            int byteCount = in.read(buffer, 0, buffer.length);
            if (byteCount <= 0) {
                break;
            }
            out.write(buffer, 0, byteCount);
            bytesCopied += byteCount;
        }
        return bytesCopied;
    }

    /**
     * Loads properties from an XML input stream into the provided properties object.
     * 
     * @param properties
     *            The object to load the properties into
     * @param inputStream
     * @throws IOException
     *             When the input stream could not be read from
     */
    public static void loadFromXml(final Properties properties, final InputStream inputStream) throws IOException {
        if (properties == null) {
            throw new IllegalArgumentException("properties must not be null");
        }
        if (inputStream == null) {
            throw new IllegalArgumentException("inputStream must not be null");
        }

        properties.loadFromXML(inputStream);
    }

    /**
     * Sets the connection to a URL as non-caching and returns the input stream.
     *
     * @param url
     *      the url to read from
     * @return the input stream for this url
     * @throws IOException when a connection cannot be opened
     */
    public static InputStream readNonCaching(final URL url) throws IOException {
        Args.notNull(url, "url");

        URLConnection urlConnection = url.openConnection();
        urlConnection.setUseCaches(false);
        InputStream inputStream = urlConnection.getInputStream();
        return inputStream;
    }

    /**
     * Reads a stream as a string.
     * 
     * @param in
     *            The input stream
     * @return The string
     * @throws IOException
     */
    public static String readString(final InputStream in) throws IOException {
        return readString(new BufferedReader(new InputStreamReader(in)));
    }

    /**
     * Reads a string using a character encoding.
     * 
     * @param in
     *            The input
     * @param encoding
     *            The character encoding of the input data
     * @return The string
     * @throws IOException
     */
    public static String readString(final InputStream in, final CharSequence encoding) throws IOException {
        return readString(new BufferedReader(new InputStreamReader(in, encoding.toString())));
    }

    /**
     * Reads all input from a reader into a string.
     * 
     * @param in
     *            The input
     * @return The string
     * @throws IOException
     */
    public static String readString(final Reader in) throws IOException {
        final StringBuilder buffer = new StringBuilder(2048);
        int value;

        while ((value = in.read()) != -1) {
            buffer.append((char) value);
        }

        return buffer.toString();
    }

    /**
     * Private to prevent instantiation.
     */
    private Streams() {
    }
}