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      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 
     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<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