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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  package org.apache.commons.launcher;
19  
20  import java.io.InputStream;
21  import java.io.IOException;
22  import java.io.OutputStream;
23  
24   /**
25   * A class for connecting an OutputStream to an InputStream.
26   *
27   * @author Patrick Luby
28   */
29  public class StreamConnector extends Thread {
30  
31      //------------------------------------------------------------------ Fields
32  
33      /**
34       * Input stream to read from.
35       */
36      private InputStream is = null;
37  
38      /**
39       * Output stream to write to.
40       */
41      private OutputStream os = null;
42  
43      //------------------------------------------------------------ Constructors
44  
45      /**
46       * Specify the streams that this object will connect in the {@link #run()}
47       * method.
48       *
49       * @param is the InputStream to read from.
50       * @param os the OutputStream to write to.
51       */
52      public StreamConnector(InputStream is, OutputStream os) {
53  
54          this.is = is;
55          this.os = os;
56  
57      }
58  
59      //----------------------------------------------------------------- Methods
60  
61      /**
62       * Connect the InputStream and OutputStream objects specified in the
63       * {@link #StreamConnector(InputStream, OutputStream)} constructor.
64       */
65      public void run() {
66  
67          // If the InputStream is null, don't do anything
68          if (is == null)
69              return;
70  
71          // Connect the streams until the InputStream is unreadable
72          try {
73              int bytesRead = 0;
74              byte[] buf = new byte[4096];
75              while ((bytesRead = is.read(buf)) != -1) {
76                  if (os != null && bytesRead > 0) {
77                      os.write(buf, 0, bytesRead);
78                      os.flush();
79                  }
80                  yield();
81              }
82          } catch (IOException e) {}
83  
84      }
85  
86  }