net.jxta.util.CountingInputStream Maven / Gradle / Ivy

/*
 * Copyright (c) 2001-2007 Sun Microsystems, Inc.  All rights reserved.
 *  
 *  The Sun Project JXTA(TM) Software License
 *  
 *  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 Sun Microsystems, Inc. for JXTA(TM) technology." 
 *     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.
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 *  5. Products derived from this software may not be called "JXTA", nor may 
 *     "JXTA" appear in their name, without prior written permission of Sun.
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 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES,
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 *  JXTA is a registered trademark of Sun Microsystems, Inc. in the United 
 *  States and other countries.
 *  
 *  Please see the license information page at :
 *   for instructions on use of 
 *  the license in source files.
 *  
 *  ====================================================================
 *  
 *  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. 
 */

package net.jxta.util;


import java.io.*;


/**
 *  A filter input stream which counts the bytes read from the stream. A filter
 *  so that you don't have to count seperately from reading from the inoput
 *
 **/
public class CountingInputStream extends FilterInputStream {
    
    /**
     *  For recursion detection to prevent overcounting.
     **/
    private transient boolean alreadycounting;
    
    /**
     *  number of bytes which have been read on this stream
     **/
    private long bytesRead = 0;
    
    /**
     *  Make a new Counting Input Stream
     **/
    public CountingInputStream(InputStream in) {
        super(in);
    }
    
    /**
     * {@inheritDoc}
     *
     *  Debugging toString.
     **/
    @Override
    public String toString() {
        if (null == in) {
            return "closed/" + super.toString();
        } else {
            return in.toString() + "/" + super.toString();
        }
    }
    
    /**
     * {@inheritDoc}
     *
     * 
Merely calls the super version.
     **/
    @Override
    public synchronized int read() throws IOException {
        boolean wascounting = alreadycounting;

        alreadycounting = true;
        int i = super.read();

        alreadycounting = wascounting;
        
        if (!alreadycounting && (i != -1)) {
            bytesRead++;
        }
        return i;
    }
    
    /**
     * {@inheritDoc}
     *
     * calls the super version of the same method.
     **/
    @Override
    public synchronized int read(byte[] b, int off, int len) throws IOException {
        boolean wascounting = alreadycounting;

        alreadycounting = true;
        
        int i = super.read(b, off, len);

        alreadycounting = wascounting;
        
        if ((-1 != i) && !alreadycounting) {
            bytesRead += i;
        }
        
        return i;
    }
    
    /**
     *  Returns the number of bytes read fromthe stream thus far. This and all
     *  the methods in this class are synchronized because bytesRead cannot be
     *  volatile.
     *
     *  @return long containing the number of bytes read.
     **/
    public synchronized long getBytesRead() {
        return bytesRead;
    }
}