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Java > Open Source Codes > org > apache > commons > httpclient > server > BidiStreamProxy


1 /*
2  * $Header: /home/cvs/jakarta-commons/httpclient/src/test/org/apache/commons/httpclient/server/BidiStreamProxy.java,v 1.1.2.2 2004/02/22 18:21:18 olegk Exp $
3  * $Revision: 1.1.2.2 $
4  * $Date: 2004/02/22 18:21:18 $
5  *
6  * ====================================================================
7  *
8  * Copyright 1999-2004 The Apache Software Foundation
9  *
10  * Licensed under the Apache License, Version 2.0 (the "License");
11  * you may not use this file except in compliance with the License.
12  * You may obtain a copy of the License at
13  *
14  * http://www.apache.org/licenses/LICENSE-2.0
15  *
16  * Unless required by applicable law or agreed to in writing, software
17  * distributed under the License is distributed on an "AS IS" BASIS,
18  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19  * See the License for the specific language governing permissions and
20  * limitations under the License.
21  * ====================================================================
22  *
23  * This software consists of voluntary contributions made by many
24  * individuals on behalf of the Apache Software Foundation. For more
25  * information on the Apache Software Foundation, please see
26  * <http://www.apache.org/>.
27  *
28  * [Additional notices, if required by prior licensing conditions]
29  *
30  */
31
32 package org.apache.commons.httpclient.server;
33
34 import java.io.InputStream JavaDoc;
35 import java.io.OutputStream JavaDoc;
36
37 /**
38  * Pumps data between a pair of input / output streams. Used to
39  * connect the two ends (left and right) of a bidirectional communication channel.
40  * Instances of this class are thread safe.
41  *
42  * @author Ortwin Glueck
43  */
44 class BidiStreamProxy {
45     private StreamProxy leftToRight, rightToLeft;
46     private int state = 0;
47     
48     /**
49      * Sets up a new connection between two peers (left and right)
50      * @param leftIn input channel of the left peer
51      * @param leftOut output channel of the left peer
52      * @param rightIn input channel of the right peer
53      * @param rightOut output channel of the right peer
54      */
55     public BidiStreamProxy(InputStream JavaDoc leftIn, OutputStream JavaDoc leftOut, InputStream JavaDoc rightIn, OutputStream JavaDoc rightOut) {
56         leftToRight = new StreamProxy(leftIn, rightOut);
57         rightToLeft = new StreamProxy(rightIn, leftOut);
58     }
59     
60     /**
61      * Starts pumping the information from left to right and vice versa.
62      * This is performed asynchronously so this method returns immediately.
63      */
64     public synchronized void start() {
65         if (state != 0) throw new IllegalStateException JavaDoc("Can not start twice");
66         leftToRight.start();
67         rightToLeft.start();
68         state = 1;
69     }
70     
71     /**
72      * Aborts the communication between the peers and releases all resources.
73      * Note: The method does not wait for the pump threads to terminate.
74      */
75     public synchronized void abort() {
76         if (leftToRight != null) leftToRight.abort();
77         if (rightToLeft != null) rightToLeft.abort();
78         leftToRight = null;
79         rightToLeft = null;
80     }
81     
82     /**
83      * Blocks until all data has been copied. Basically calls the
84      * join method on the pump thread.
85      * @throws InterruptedException
86      */
87     public void block() throws InterruptedException JavaDoc {
88         if (state != 1) throw new IllegalStateException JavaDoc("Can not block before started");
89         leftToRight.block();
90         rightToLeft.block();
91     }
92 }
93
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