src/java/org/apache/commons/fileupload/StreamUtil.java

package org.apache.commons.fileupload;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;


/** Utility class for working with streams.
 */
public class StreamUtil {
    /**
     * Copies the contents of the given {@link InputStream}
     * to the given {@link OutputStream}. Shortcut for
     * <pre>
     *   copy(pInputStream, pOutputStream, new byte[8192]);
     * </pre>
     * @param pInputStream The input stream, which is being read.
     * It is guaranteed, that {@link InputStream#close()} is called
     * on the stream.
     * @param pOutputStream The output stream, to which data should
     * be written. May be null, in which case the input streams
     * contents are simply discarded.
     * @param pClose True guarantees, that {@link OutputStream#close()}
     * is called on the stream. False indicates, that only
     * {@link OutputStream#flush()} should be called finally.
     * 
     * @return Number of bytes, which have been copied.
     */
    public static long copy(InputStream pInputStream,
                OutputStream pOutputStream, boolean pClose)
            throws IOException {
        return copy(pInputStream, pOutputStream, pClose, new byte[8192]);
    }

    /**
     * Copies the contents of the given {@link InputStream}
     * to the given {@link OutputStream}. Shortcut for
     * <pre>
     *   copy(pInputStream, pOutputStream, new byte[8192]);
     * </pre>
     * @param pInputStream The input stream, which is being read.
     * It is guaranteed, that {@link InputStream#close()} is called
     * on the stream.
     * @param pOutputStream The output stream, to which data should
     * be written. May be null, in which case the input streams
     * contents are simply discarded.
     * @param pClose True guarantees, that {@link OutputStream#close()}
     * is called on the stream. False indicates, that only
     * {@link OutputStream#flush()} should be called finally.
     * @param pBuffer Temporary buffer, which is to be used for
     * copying data.
     * @return Number of bytes, which have been copied.
     */
    public static long copy(InputStream pInputStream,
                OutputStream pOutputStream, boolean pClose,
                byte[] pBuffer)
            throws IOException {
        try {
            long total = 0;
            for (;;) {
                int res = pInputStream.read(pBuffer);
                if (res == -1) {
                    break;
                }
                if (res > 0) {
                    total += res;
                    if (pOutputStream != null) {
                        pOutputStream.write(pBuffer, 0, res);
                    }
                }
            }
            if (pOutputStream != null) {
                if (pClose) {
                    pOutputStream.close();
                } else {
                    pOutputStream.flush();
                }
                pOutputStream = null;
            }
            pInputStream.close();
            pInputStream = null;
            return total;
        } finally {
            if (pInputStream != null) {
                try {
                    pInputStream.close();
                } catch (Throwable t) {
                    /* Ignore me */
                }
            }
            if (pClose  &&  pOutputStream != null) {
                try {
                    pOutputStream.close();
                } catch (Throwable t) {
                    /* Ignore me */
                }
            }
        }
    }

    /**
     * This convenience method allows to read a {@link FileItemStream}'s
     * content into a string. The platform's default character encoding
     * is used for converting bytes into characters.
     * @param pStream The input stream to read.
     * @see #asString(InputStream, String)
     */
    public String asString(InputStream pStream) throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        copy(pStream, baos, true);
        return baos.toString();
    }

    /**
     * This convenience method allows to read a {@link FileItemStream}'s
     * content into a string, using the given character encoding.
     * @param pStream The input stream to read.
     * @param pEncoding The character encoding, typically "UTF-8".
     * @see #asString(InputStream)
     */
    public String asString(InputStream pStream, String pEncoding)
            throws IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        copy(pStream, baos, true);
        return baos.toString(pEncoding);
    }
}