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Java > Open Source Codes > com > quadcap > io > ConcatInputStream


1 package com.quadcap.io;
2
3 /* Copyright 1997 - 2003 Quadcap Software. All rights reserved.
4  *
5  * This software is distributed under the Quadcap Free Software License.
6  * This software may be used or modified for any purpose, personal or
7  * commercial. Open Source redistributions are permitted. Commercial
8  * redistribution of larger works derived from, or works which bundle
9  * this software requires a "Commercial Redistribution License"; see
10  * http://www.quadcap.com/purchase.
11  *
12  * Redistributions qualify as "Open Source" under one of the following terms:
13  *
14  * Redistributions are made at no charge beyond the reasonable cost of
15  * materials and delivery.
16  *
17  * Redistributions are accompanied by a copy of the Source Code or by an
18  * irrevocable offer to provide a copy of the Source Code for up to three
19  * years at the cost of materials and delivery. Such redistributions
20  * must allow further use, modification, and redistribution of the Source
21  * Code under substantially the same terms as this license.
22  *
23  * Redistributions of source code must retain the copyright notices as they
24  * appear in each source code file, these license terms, and the
25  * disclaimer/limitation of liability set forth as paragraph 6 below.
26  *
27  * Redistributions in binary form must reproduce this Copyright Notice,
28  * these license terms, and the disclaimer/limitation of liability set
29  * forth as paragraph 6 below, in the documentation and/or other materials
30  * provided with the distribution.
31  *
32  * The Software is provided on an "AS IS" basis. No warranty is
33  * provided that the Software is free of defects, or fit for a
34  * particular purpose.
35  *
36  * Limitation of Liability. Quadcap Software shall not be liable
37  * for any damages suffered by the Licensee or any third party resulting
38  * from use of the Software.
39  */
40
41 import java.io.InputStream JavaDoc;
42 import java.io.IOException JavaDoc;
43
44 import java.util.Vector JavaDoc;
45
46 import com.quadcap.util.Debug;
47
48 /**
49  * This class implements an input stream which is formed by the concatenation
50  * of two or more separate input streams.
51  *
52  * @author Stan Bailes
53  */
54 public class ConcatInputStream extends InputStream JavaDoc {
55     Vector JavaDoc streams = new Vector JavaDoc();
56     int stream = 0;
57
58     /**
59      * Construct a new ConcatInputStream formed by the concatenation of
60      * two input streams.
61      *
62      * @param in1 the first input stream
63      * @param in2 the second input stream
64      */
65     public ConcatInputStream(InputStream JavaDoc in1, InputStream JavaDoc in2) {
66     streams.addElement(in1);
67     streams.addElement(in2);
68     }
69
70     /**
71      * Add another input stream to the concatenation.
72      *
73      * @param in the input stream to add.
74      */
75     public void addInputStream(InputStream JavaDoc in) {
76     streams.addElement(in);
77     }
78
79     /**
80      * Reads the next byte of data from this input stream. The value
81      * byte is returned as an <code>int</code> in the range
82      * <code>0</code> to <code>255</code>. If no byte is available
83      * because the end of the stream has been reached, the value
84      * <code>-1</code> is returned. This method blocks until input data
85      * is available, the end of the stream is detected, or an exception
86      * is thrown.
87      * <p>
88      *
89      * @return the next byte of data, or <code>-1</code> if the end of the
90      * stream is reached.
91      * @exception IOException if an I/O error occurs.
92      */
93     public int read() throws IOException JavaDoc {
94     while (stream < streams.size()) {
95         InputStream JavaDoc is = (InputStream JavaDoc)streams.elementAt(stream);
96         int c = is.read();
97         if (c >= 0) return c;
98         stream++;
99     }
100     return -1;
101     }
102
103     /**
104      * Returns the number of bytes that can be read from this input
105      * stream without blocking. The available method of
106      * <code>InputStream</code> returns <code>0</code>.
107      *
108      * @return the number of bytes that can be read from this input stream
109      * without blocking.
110      * @exception IOException if an I/O error occurs.
111      */
112     public int available() throws IOException JavaDoc {
113     int avail = 0;
114     for (int i = stream; i < streams.size(); i++) {
115         InputStream JavaDoc is = (InputStream JavaDoc)streams.elementAt(i);
116         avail += is.available();
117     }
118     return avail;
119     }
120         
121 }
122
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