001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. 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 */ 017 package org.apache.commons.io.output; 018 019 import java.io.IOException; 020 import java.io.OutputStream; 021 022 /** 023 * Data written to this stream is forwarded to a stream that has been associated 024 * with this thread. 025 * 026 * @author <a href="mailto:peter@apache.org">Peter Donald</a> 027 * @version $Revision: 736890 $ $Date: 2009-01-22 21:02:22 -0500 (Thu, 22 Jan 2009) $ 028 */ 029 public class DemuxOutputStream 030 extends OutputStream 031 { 032 private final InheritableThreadLocal<OutputStream> m_streams = new InheritableThreadLocal<OutputStream>(); 033 034 /** 035 * Bind the specified stream to the current thread. 036 * 037 * @param output the stream to bind 038 * @return the OutputStream that was previously active 039 */ 040 public OutputStream bindStream( OutputStream output ) 041 { 042 OutputStream stream = m_streams.get(); 043 m_streams.set( output ); 044 return stream; 045 } 046 047 /** 048 * Closes stream associated with current thread. 049 * 050 * @throws IOException if an error occurs 051 */ 052 @Override 053 public void close() 054 throws IOException 055 { 056 OutputStream output = m_streams.get(); 057 if( null != output ) 058 { 059 output.close(); 060 } 061 } 062 063 /** 064 * Flushes stream associated with current thread. 065 * 066 * @throws IOException if an error occurs 067 */ 068 @Override 069 public void flush() 070 throws IOException 071 { 072 OutputStream output = m_streams.get(); 073 if( null != output ) 074 { 075 output.flush(); 076 } 077 } 078 079 /** 080 * Writes byte to stream associated with current thread. 081 * 082 * @param ch the byte to write to stream 083 * @throws IOException if an error occurs 084 */ 085 @Override 086 public void write( int ch ) 087 throws IOException 088 { 089 OutputStream output = m_streams.get(); 090 if( null != output ) 091 { 092 output.write( ch ); 093 } 094 } 095 }