Quadcap Embeddable Server

com/quadcap/io/ConcatInputStream.java

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package com.quadcap.io;

/* Copyright 1997 - 2003 Quadcap Software.  All rights reserved.
 *
 * This software is distributed under the Quadcap Free Software License.
 * This software may be used or modified for any purpose, personal or
 * commercial.  Open Source redistributions are permitted.  Commercial
 * redistribution of larger works derived from, or works which bundle
 * this software requires a "Commercial Redistribution License"; see
 * http://www.quadcap.com/purchase.
 *
 * Redistributions qualify as "Open Source" under  one of the following terms:
 *   
 *    Redistributions are made at no charge beyond the reasonable cost of
 *    materials and delivery.
 *
 *    Redistributions are accompanied by a copy of the Source Code or by an
 *    irrevocable offer to provide a copy of the Source Code for up to three
 *    years at the cost of materials and delivery.  Such redistributions
 *    must allow further use, modification, and redistribution of the Source
 *    Code under substantially the same terms as this license.
 *
 * Redistributions of source code must retain the copyright notices as they
 * appear in each source code file, these license terms, and the
 * disclaimer/limitation of liability set forth as paragraph 6 below.
 *
 * Redistributions in binary form must reproduce this Copyright Notice,
 * these license terms, and the disclaimer/limitation of liability set
 * forth as paragraph 6 below, in the documentation and/or other materials
 * provided with the distribution.
 *
 * The Software is provided on an "AS IS" basis.  No warranty is
 * provided that the Software is free of defects, or fit for a
 * particular purpose.  
 *
 * Limitation of Liability. Quadcap Software shall not be liable
 * for any damages suffered by the Licensee or any third party resulting
 * from use of the Software.
 */

import java.io.InputStream;
import java.io.IOException;

import java.util.Vector;

import com.quadcap.util.Debug;

/**
 * This class implements an input stream which is formed by the concatenation
 * of two or more separate input streams.
 *
 * @author Stan Bailes
 */
public class ConcatInputStream extends InputStream {
    Vector                      streams = new Vector();
    int                         stream = 0;

    /**
     * Construct a new ConcatInputStream formed by the concatenation of
     * two input streams.
     *
     * @param in1 the first input stream
     * @param in2 the second input stream
     */
    public ConcatInputStream(InputStream in1, InputStream in2) {
        streams.addElement(in1);
        streams.addElement(in2);
    }

    /**
     * Add another input stream to the concatenation.
     *
     * @param in the input stream to add.
     */
    public void addInputStream(InputStream in) {
        streams.addElement(in);
    }

    /**
     * Reads the next byte of data from this input stream. The value 
     * byte is returned as an <code>int</code> in the range 
     * <code>0</code> to <code>255</code>. If no byte is available 
     * because the end of the stream has been reached, the value 
     * <code>-1</code> is returned. This method blocks until input data 
     * is available, the end of the stream is detected, or an exception 
     * is thrown. 
     * <p>
     *
     * @return     the next byte of data, or <code>-1</code> if the end of the
     *             stream is reached.
     * @exception  IOException  if an I/O error occurs.
     */
    public int read() throws IOException {
        while (stream < streams.size()) {
            InputStream is = (InputStream)streams.elementAt(stream);
            int c = is.read();
            if (c >= 0) return c;
            stream++;
        }
        return -1;
    }

    /**
     * Returns the number of bytes that can be read from this input 
     * stream without blocking. The available method of 
     * <code>InputStream</code> returns <code>0</code>.
     *
     * @return     the number of bytes that can be read from this input stream
     *             without blocking.
     * @exception  IOException  if an I/O error occurs.
     */
    public int available() throws IOException {
        int avail = 0;
        for (int i = stream; i < streams.size(); i++) {
            InputStream is = (InputStream)streams.elementAt(i);
            avail += is.available();
        }
        return avail;
    }
            
}