001/**
002 *
003 * Copyright 2003-2007 Jive Software.
004 *
005 * Licensed under the Apache License, Version 2.0 (the "License");
006 * you may not use this file except in compliance with the License.
007 * You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.jivesoftware.smack.util;
018
019import java.io.IOException;
020import java.io.Reader;
021import java.util.ArrayList;
022import java.util.List;
023
024
025/**
026 * An ObservableReader is a wrapper on a Reader that notifies to its listeners when
027 * reading character streams.
028 *
029 * @author Gaston Dombiak
030 */
031public class ObservableReader extends Reader {
032
033    Reader wrappedReader = null;
034    final List<ReaderListener> listeners = new ArrayList<ReaderListener>();
035
036    public ObservableReader(Reader wrappedReader) {
037        this.wrappedReader = wrappedReader;
038    }
039
040    @Override
041    public int read(char[] cbuf, int off, int len) throws IOException {
042        int count = wrappedReader.read(cbuf, off, len);
043        if (count > 0) {
044            String str = new String(cbuf, off, count);
045            // Notify that a new string has been read
046            ReaderListener[] readerListeners = null;
047            synchronized (listeners) {
048                readerListeners = new ReaderListener[listeners.size()];
049                listeners.toArray(readerListeners);
050            }
051            for (int i = 0; i < readerListeners.length; i++) {
052                readerListeners[i].read(str);
053            }
054        }
055        return count;
056    }
057
058    @Override
059    public void close() throws IOException {
060        wrappedReader.close();
061    }
062
063    @Override
064    public int read() throws IOException {
065        return wrappedReader.read();
066    }
067
068    @Override
069    public int read(char[] cbuf) throws IOException {
070        return wrappedReader.read(cbuf);
071    }
072
073    @Override
074    public long skip(long n) throws IOException {
075        return wrappedReader.skip(n);
076    }
077
078    @Override
079    public boolean ready() throws IOException {
080        return wrappedReader.ready();
081    }
082
083    @Override
084    public boolean markSupported() {
085        return wrappedReader.markSupported();
086    }
087
088    @Override
089    public void mark(int readAheadLimit) throws IOException {
090        wrappedReader.mark(readAheadLimit);
091    }
092
093    @Override
094    public void reset() throws IOException {
095        wrappedReader.reset();
096    }
097
098    /**
099     * Adds a reader listener to this reader that will be notified when
100     * new strings are read.
101     *
102     * @param readerListener a reader listener.
103     */
104    public void addReaderListener(ReaderListener readerListener) {
105        if (readerListener == null) {
106            return;
107        }
108        synchronized (listeners) {
109            if (!listeners.contains(readerListener)) {
110                listeners.add(readerListener);
111            }
112        }
113    }
114
115    /**
116     * Removes a reader listener from this reader.
117     *
118     * @param readerListener a reader listener.
119     */
120    public void removeReaderListener(ReaderListener readerListener) {
121        synchronized (listeners) {
122            listeners.remove(readerListener);
123        }
124    }
125
126}