countingoutputstream.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

/*
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 *
 * $Id: CountingOutputStream.java,v 1.1 2002/06/03 20:48:20 bondolo Exp $
 */

package net.jxta.util;

import java.io.OutputStream;
import java.io.IOException;

/**
 *  A filter output stream which counts the bytes sent to the stream. A filter
 *  so that you don't have to count seperately from writing to the output
 *
 **/
public class CountingOutputStream extends java.io.FilterOutputStream {
  
  private transient long bytesWritten;

  private transient boolean alreadycounting;

  /** Creates a new instance of CountingOutputStream */
  public CountingOutputStream( OutputStream out ) {
    super( out );
    bytesWritten = 0;
    alreadycounting = false;
  }
  
  /**
   * Writes <code>b.length</code> bytes to this output stream.
   * <p>
   * The <code>write</code> method of <code>FilterOutputStream</code>
   * calls its <code>write</code> method of three arguments with the
   * arguments <code>b</code>, <code>0</code>, and
   * <code>b.length</code>.
   * <p>
   * Note that this method does not call the one-argument
   * <code>write</code> method of its underlying stream with the single
   * argument <code>b</code>.
   *
   * @param      b   the data to be written.
   * @exception  IOException  if an I/O error occurs.
   * @see        java.io.FilterOutputStream#write(byte[], int, int)
   */
  public synchronized void write(byte[] b) throws IOException {
    boolean wascounting = alreadycounting;
    alreadycounting = true;
    super.write( b );
    alreadycounting = wascounting;
    if( !alreadycounting )
      bytesWritten += b.length;
  }
  
  /**
   * Writes the specified <code>byte</code> to this output stream.
   * <p>
   * The <code>write</code> method of <code>FilterOutputStream</code>
   * calls the <code>write</code> method of its underlying output stream,
   * that is, it performs <tt>out.write(b)</tt>.
   * <p>
   * Implements the abstract <tt>write</tt> method of <tt>OutputStream</tt>.
   *
   * @param      b   the <code>byte</code>.
   * @exception  IOException  if an I/O error occurs.
   */
  public synchronized void write(int b) throws IOException {
    boolean wascounting = alreadycounting;
    alreadycounting = true;
    super.write( b );
    alreadycounting = wascounting;
    if( !alreadycounting )
      bytesWritten += 1;
  }
  
  /**
   * Writes <code>len</code> bytes from the specified
   * <code>byte</code> array starting at offset <code>off</code> to
   * this output stream.
   * <p>
   * The <code>write</code> method of <code>FilterOutputStream</code>
   * calls the <code>write</code> method of one argument on each
   * <code>byte</code> to output.
   * <p>
   * Note that this method does not call the <code>write</code> method
   * of its underlying input stream with the same arguments. Subclasses
   * of <code>FilterOutputStream</code> should provide a more efficient
   * implementation of this method.
   *
   * @param      b     the data.
   * @param      off   the start offset in the data.
   * @param      len   the number of bytes to write.
   * @exception  IOException  if an I/O error occurs.
   * @see        java.io.FilterOutputStream#write(int)
   */
  public synchronized void write(byte[] b, int off, int len) throws IOException {
    boolean wascounting = alreadycounting;
    alreadycounting = true;
    super.write( b, off, len );
    alreadycounting = wascounting;
    if( !alreadycounting )
      bytesWritten += len;
  }
  
  /**
   *  Returns the number of bytes written to the stream thus far. This and all
   *  the methods in this class are synchronized because bytesWritten cannot be
   *  volatile.
   **/
  public synchronized long getBytesWritten() {
    return bytesWritten;
  }
  
}