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.*; 020import java.util.*; 021 022/** 023 * An ObservableWriter is a wrapper on a Writer that notifies to its listeners when 024 * writing to character streams. 025 * 026 * @author Gaston Dombiak 027 */ 028public class ObservableWriter extends Writer { 029 030 Writer wrappedWriter = null; 031 List<WriterListener> listeners = new ArrayList<WriterListener>(); 032 033 public ObservableWriter(Writer wrappedWriter) { 034 this.wrappedWriter = wrappedWriter; 035 } 036 037 public void write(char cbuf[], int off, int len) throws IOException { 038 wrappedWriter.write(cbuf, off, len); 039 String str = new String(cbuf, off, len); 040 notifyListeners(str); 041 } 042 043 public void flush() throws IOException { 044 wrappedWriter.flush(); 045 } 046 047 public void close() throws IOException { 048 wrappedWriter.close(); 049 } 050 051 public void write(int c) throws IOException { 052 wrappedWriter.write(c); 053 } 054 055 public void write(char cbuf[]) throws IOException { 056 wrappedWriter.write(cbuf); 057 String str = new String(cbuf); 058 notifyListeners(str); 059 } 060 061 public void write(String str) throws IOException { 062 wrappedWriter.write(str); 063 notifyListeners(str); 064 } 065 066 public void write(String str, int off, int len) throws IOException { 067 wrappedWriter.write(str, off, len); 068 str = str.substring(off, off + len); 069 notifyListeners(str); 070 } 071 072 /** 073 * Notify that a new string has been written. 074 * 075 * @param str the written String to notify 076 */ 077 private void notifyListeners(String str) { 078 WriterListener[] writerListeners = null; 079 synchronized (listeners) { 080 writerListeners = new WriterListener[listeners.size()]; 081 listeners.toArray(writerListeners); 082 } 083 for (int i = 0; i < writerListeners.length; i++) { 084 writerListeners[i].write(str); 085 } 086 } 087 088 /** 089 * Adds a writer listener to this writer that will be notified when 090 * new strings are sent. 091 * 092 * @param writerListener a writer listener. 093 */ 094 public void addWriterListener(WriterListener writerListener) { 095 if (writerListener == null) { 096 return; 097 } 098 synchronized (listeners) { 099 if (!listeners.contains(writerListener)) { 100 listeners.add(writerListener); 101 } 102 } 103 } 104 105 /** 106 * Removes a writer listener from this writer. 107 * 108 * @param writerListener a writer listener. 109 */ 110 public void removeWriterListener(WriterListener writerListener) { 111 synchronized (listeners) { 112 listeners.remove(writerListener); 113 } 114 } 115 116}