1/**
2 * $RCSfile$
3 * $Revision$
4 * $Date$
5 *
6 * Copyright 2003-2007 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
21package org.jivesoftware.smack.util;
22
23import java.io.*;
24import 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 */
32public class ObservableWriter extends Writer {
33
34    Writer wrappedWriter = null;
35    List<WriterListener> listeners = new ArrayList<WriterListener>();
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 str = new String(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 str = new String(cbuf);
62        notifyListeners(str);
63    }
64
65    public void write(String str) throws IOException {
66        wrappedWriter.write(str);
67        notifyListeners(str);
68    }
69
70    public void write(String 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 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