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Java > Open Source Codes > org > jivesoftware > smack > util > ObservableWriter


1 /**
2  * $RCSfile$
3  * $Revision: 2408 $
4  * $Date: 2004-11-02 20:53:30 -0300 (Tue, 02 Nov 2004) $
5  *
6  * Copyright 2003-2004 Jive Software.
7  *
8  * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
9  * you may not use this file except in compliance with the License.
10  * You may obtain a copy of the License at
11  *
12  * http://www.apache.org/licenses/LICENSE-2.0
13  *
14  * Unless required by applicable law or agreed to in writing, software
15  * distributed under the License is distributed on an "AS IS" BASIS,
16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17  * See the License for the specific language governing permissions and
18  * limitations under the License.
19  */
20
21 package org.jivesoftware.smack.util;
22
23 import java.io.*;
24 import java.util.*;
25
26 /**
27  * An ObservableWriter is a wrapper on a Writer that notifies to its listeners when
28  * writing to character streams.
29  *
30  * @author Gaston Dombiak
31  */
32 public class ObservableWriter extends Writer {
33
34     Writer wrappedWriter = null;
35     List listeners = new ArrayList();
36
37     public ObservableWriter(Writer wrappedWriter) {
38         this.wrappedWriter = wrappedWriter;
39     }
40
41     public void write(char cbuf[], int off, int len) throws IOException {
42         wrappedWriter.write(cbuf, off, len);
43         String JavaDoc str = new String JavaDoc(cbuf, off, len);
44         notifyListeners(str);
45     }
46
47     public void flush() throws IOException {
48         wrappedWriter.flush();
49     }
50
51     public void close() throws IOException {
52         wrappedWriter.close();
53     }
54
55     public void write(int c) throws IOException {
56         wrappedWriter.write(c);
57     }
58
59     public void write(char cbuf[]) throws IOException {
60         wrappedWriter.write(cbuf);
61         String JavaDoc str = new String JavaDoc(cbuf);
62         notifyListeners(str);
63     }
64
65     public void write(String JavaDoc str) throws IOException {
66         wrappedWriter.write(str);
67         notifyListeners(str);
68     }
69
70     public void write(String JavaDoc str, int off, int len) throws IOException {
71         wrappedWriter.write(str, off, len);
72         str = str.substring(off, off + len);
73         notifyListeners(str);
74     }
75
76     /**
77      * Notify that a new string has been written.
78      *
79      * @param str the written String to notify
80      */
81     private void notifyListeners(String JavaDoc str) {
82         WriterListener[] writerListeners = null;
83         synchronized (listeners) {
84             writerListeners = new WriterListener[listeners.size()];
85             listeners.toArray(writerListeners);
86         }
87         for (int i = 0; i < writerListeners.length; i++) {
88             writerListeners[i].write(str);
89         }
90     }
91
92     /**
93      * Adds a writer listener to this writer that will be notified when
94      * new strings are sent.
95      *
96      * @param writerListener a writer listener.
97      */
98     public void addWriterListener(WriterListener writerListener) {
99         if (writerListener == null) {
100             return;
101         }
102         synchronized (listeners) {
103             if (!listeners.contains(writerListener)) {
104                 listeners.add(writerListener);
105             }
106         }
107     }
108
109     /**
110      * Removes a writer listener from this writer.
111      *
112      * @param writerListener a writer listener.
113      */
114     public void removeWriterListener(WriterListener writerListener) {
115         synchronized (listeners) {
116             listeners.remove(writerListener);
117         }
118     }
119
120 }
121
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