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Commons Net example source code file (Util.java)

This example Commons Net source code file (Util.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Net tags/keywords

copystreamexception, copystreamexception, copystreamlistener, default_copy_buffer_size, io, ioexception, ioexception, net, network, outputstream, outputstream, util, writer, writer

The Commons Net Util.java source code

/*
 * 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.commons.net.io;

import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.Writer;
import java.net.Socket;

/***
 * The Util class cannot be instantiated and stores short static convenience
 * methods that are often quite useful.
 * <p>
 * <p>
 * @see CopyStreamException
 * @see CopyStreamListener
 * @see CopyStreamAdapter
 ***/

public final class Util
{
    /***
     * The default buffer size used by {@link #copyStream  copyStream }
     * and {@link #copyReader  copyReader }. It's value is 1024.
     ***/
    public static final int DEFAULT_COPY_BUFFER_SIZE = 1024;

    // Cannot be instantiated
    private Util()
    { }


    /***
     * Copies the contents of an InputStream to an OutputStream using a
     * copy buffer of a given size and notifies the provided
     * CopyStreamListener of the progress of the copy operation by calling
     * its bytesTransferred(long, int) method after each write to the
     * destination.  If you wish to notify more than one listener you should
     * use a CopyStreamAdapter as the listener and register the additional
     * listeners with the CopyStreamAdapter.
     * <p>
     * The contents of the InputStream are
     * read until the end of the stream is reached, but neither the
     * source nor the destination are closed.  You must do this yourself
     * outside of the method call.  The number of bytes read/written is
     * returned.
     * <p>
     * @param source  The source InputStream.
     * @param dest    The destination OutputStream.
     * @param bufferSize  The number of bytes to buffer during the copy.
     * @param streamSize  The number of bytes in the stream being copied.
     *          Should be set to CopyStreamEvent.UNKNOWN_STREAM_SIZE if unknown.
     * @param listener  The CopyStreamListener to notify of progress.  If
     *      this parameter is null, notification is not attempted.
     * @param flush Whether to flush the output stream after every
     *        write.  This is necessary for interactive sessions that rely on
     *        buffered streams.  If you don't flush, the data will stay in
     *        the stream buffer.
     * @exception CopyStreamException  If an error occurs while reading from the
     *            source or writing to the destination.  The CopyStreamException
     *            will contain the number of bytes confirmed to have been
     *            transferred before an
     *            IOException occurred, and it will also contain the IOException
     *            that caused the error.  These values can be retrieved with
     *            the CopyStreamException getTotalBytesTransferred() and
     *            getIOException() methods.
     ***/
    public static final long copyStream(InputStream source, OutputStream dest,
                                        int bufferSize, long streamSize,
                                        CopyStreamListener listener,
                                        boolean flush)
    throws CopyStreamException
    {
        int bytes;
        long total;
        byte[] buffer;

        buffer = new byte[bufferSize];
        total = 0;

        try
        {
            while ((bytes = source.read(buffer)) != -1)
            {
                // Technically, some read(byte[]) methods may return 0 and we cannot
                // accept that as an indication of EOF.

                if (bytes == 0)
                {
                    bytes = source.read();
                    if (bytes < 0)
                        break;
                    dest.write(bytes);
                    if(flush)
                      dest.flush();
                    ++total;
                    if (listener != null)
                        listener.bytesTransferred(total, 1, streamSize);
                    continue;
                }

                dest.write(buffer, 0, bytes);
                if(flush)
                  dest.flush();
                total += bytes;
                if (listener != null)
                    listener.bytesTransferred(total, bytes, streamSize);
            }
        }
        catch (IOException e)
        {
            throw new CopyStreamException("IOException caught while copying.",
                                          total, e);
        }

        return total;
    }


    /***
     * Copies the contents of an InputStream to an OutputStream using a
     * copy buffer of a given size and notifies the provided
     * CopyStreamListener of the progress of the copy operation by calling
     * its bytesTransferred(long, int) method after each write to the
     * destination.  If you wish to notify more than one listener you should
     * use a CopyStreamAdapter as the listener and register the additional
     * listeners with the CopyStreamAdapter.
     * <p>
     * The contents of the InputStream are
     * read until the end of the stream is reached, but neither the
     * source nor the destination are closed.  You must do this yourself
     * outside of the method call.  The number of bytes read/written is
     * returned.
     * <p>
     * @param source  The source InputStream.
     * @param dest    The destination OutputStream.
     * @param bufferSize  The number of bytes to buffer during the copy.
     * @param streamSize  The number of bytes in the stream being copied.
     *          Should be set to CopyStreamEvent.UNKNOWN_STREAM_SIZE if unknown.
     * @param listener  The CopyStreamListener to notify of progress.  If
     *      this parameter is null, notification is not attempted.
     * @exception CopyStreamException  If an error occurs while reading from the
     *            source or writing to the destination.  The CopyStreamException
     *            will contain the number of bytes confirmed to have been
     *            transferred before an
     *            IOException occurred, and it will also contain the IOException
     *            that caused the error.  These values can be retrieved with
     *            the CopyStreamException getTotalBytesTransferred() and
     *            getIOException() methods.
     ***/
    public static final long copyStream(InputStream source, OutputStream dest,
                                        int bufferSize, long streamSize,
                                        CopyStreamListener listener)
    throws CopyStreamException
    {
      return copyStream(source, dest, bufferSize, streamSize, listener,
                        true);
    }


    /***
     * Copies the contents of an InputStream to an OutputStream using a
     * copy buffer of a given size.  The contents of the InputStream are
     * read until the end of the stream is reached, but neither the
     * source nor the destination are closed.  You must do this yourself
     * outside of the method call.  The number of bytes read/written is
     * returned.
     * <p>
     * @param source  The source InputStream.
     * @param dest    The destination OutputStream.
     * @return  The number of bytes read/written in the copy operation.
     * @exception CopyStreamException  If an error occurs while reading from the
     *            source or writing to the destination.  The CopyStreamException
     *            will contain the number of bytes confirmed to have been
     *            transferred before an
     *            IOException occurred, and it will also contain the IOException
     *            that caused the error.  These values can be retrieved with
     *            the CopyStreamException getTotalBytesTransferred() and
     *            getIOException() methods.
     ***/
    public static final long copyStream(InputStream source, OutputStream dest,
                                        int bufferSize)
    throws CopyStreamException
    {
        return copyStream(source, dest, bufferSize,
                          CopyStreamEvent.UNKNOWN_STREAM_SIZE, null);
    }


    /***
     * Same as <code> copyStream(source, dest, DEFAULT_COPY_BUFFER_SIZE); 
     ***/
    public static final long copyStream(InputStream source, OutputStream dest)
    throws CopyStreamException
    {
        return copyStream(source, dest, DEFAULT_COPY_BUFFER_SIZE);
    }


    /***
     * Copies the contents of a Reader to a Writer using a
     * copy buffer of a given size and notifies the provided
     * CopyStreamListener of the progress of the copy operation by calling
     * its bytesTransferred(long, int) method after each write to the
     * destination.  If you wish to notify more than one listener you should
     * use a CopyStreamAdapter as the listener and register the additional
     * listeners with the CopyStreamAdapter.
     * <p>
     * The contents of the Reader are
     * read until its end is reached, but neither the source nor the
     * destination are closed.  You must do this yourself outside of the
     * method call.  The number of characters read/written is returned.
     * <p>
     * @param source  The source Reader.
     * @param dest    The destination writer.
     * @param bufferSize  The number of characters to buffer during the copy.
     * @param streamSize  The number of characters in the stream being copied.
     *          Should be set to CopyStreamEvent.UNKNOWN_STREAM_SIZE if unknown.
     * @param listener  The CopyStreamListener to notify of progress.  If
     *      this parameter is null, notification is not attempted.
     * @return  The number of characters read/written in the copy operation.
     * @exception CopyStreamException  If an error occurs while reading from the
     *            source or writing to the destination.  The CopyStreamException
     *            will contain the number of bytes confirmed to have been
     *            transferred before an
     *            IOException occurred, and it will also contain the IOException
     *            that caused the error.  These values can be retrieved with
     *            the CopyStreamException getTotalBytesTransferred() and
     *            getIOException() methods.
     ***/
    public static final long copyReader(Reader source, Writer dest,
                                        int bufferSize, long streamSize,
                                        CopyStreamListener listener)
    throws CopyStreamException
    {
        int chars;
        long total;
        char[] buffer;

        buffer = new char[bufferSize];
        total = 0;

        try
        {
            while ((chars = source.read(buffer)) != -1)
            {
                // Technically, some read(char[]) methods may return 0 and we cannot
                // accept that as an indication of EOF.
                if (chars == 0)
                {
                    chars = source.read();
                    if (chars < 0)
                        break;
                    dest.write(chars);
                    dest.flush();
                    ++total;
                    if (listener != null)
                        listener.bytesTransferred(total, chars, streamSize);
                    continue;
                }

                dest.write(buffer, 0, chars);
                dest.flush();
                total += chars;
                if (listener != null)
                    listener.bytesTransferred(total, chars, streamSize);
            }
        }
        catch (IOException e)
        {
            throw new CopyStreamException("IOException caught while copying.",
                                          total, e);
        }

        return total;
    }


    /***
     * Copies the contents of a Reader to a Writer using a
     * copy buffer of a given size.  The contents of the Reader are
     * read until its end is reached, but neither the source nor the
     * destination are closed.  You must do this yourself outside of the
     * method call.  The number of characters read/written is returned.
     * <p>
     * @param source  The source Reader.
     * @param dest    The destination writer.
     * @param bufferSize  The number of characters to buffer during the copy.
     * @return  The number of characters read/written in the copy operation.
     * @exception CopyStreamException  If an error occurs while reading from the
     *            source or writing to the destination.  The CopyStreamException
     *            will contain the number of bytes confirmed to have been
     *            transferred before an
     *            IOException occurred, and it will also contain the IOException
     *            that caused the error.  These values can be retrieved with
     *            the CopyStreamException getTotalBytesTransferred() and
     *            getIOException() methods.
     ***/
    public static final long copyReader(Reader source, Writer dest,
                                        int bufferSize)
    throws CopyStreamException
    {
        return copyReader(source, dest, bufferSize,
                          CopyStreamEvent.UNKNOWN_STREAM_SIZE, null);
    }


    /***
     * Same as <code> copyReader(source, dest, DEFAULT_COPY_BUFFER_SIZE); 
     ***/
    public static final long copyReader(Reader source, Writer dest)
    throws CopyStreamException
    {
        return copyReader(source, dest, DEFAULT_COPY_BUFFER_SIZE);
    }

    /**
     * Closes the object quietly, catching rather than throwing IOException.
     * Intended for use from finally blocks.
     *
     * @param closeable the object to close, may be {@code null}
     * @since 3.0
     */
    public static void closeQuietly(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (IOException e) {
            }
        }
    }

    /**
     * Closes the socket quietly, catching rather than throwing IOException.
     * Intended for use from finally blocks.
     *
     * @param socket the socket to close, may be {@code null}
     * @since 3.0
     */
    public static void closeQuietly(Socket socket) {
        if (socket != null) {
            try {
                socket.close();
            } catch (IOException e) {
            }
        }
    }
}

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