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 */ 017package org.apache.commons.io.output; 018 019import java.io.IOException; 020import java.io.OutputStream; 021 022/** 023 * Forwards data to a stream that has been associated with this thread. 024 * 025 * @version $Id: DemuxOutputStream.java 1737901 2016-04-06 00:23:36Z ggregory $ 026 */ 027public class DemuxOutputStream extends OutputStream { 028 private final InheritableThreadLocal<OutputStream> outputStreamThreadLocal = new InheritableThreadLocal<OutputStream>(); 029 030 /** 031 * Binds the specified stream to the current thread. 032 * 033 * @param output 034 * the stream to bind 035 * @return the OutputStream that was previously active 036 */ 037 public OutputStream bindStream(final OutputStream output) { 038 final OutputStream stream = outputStreamThreadLocal.get(); 039 outputStreamThreadLocal.set(output); 040 return stream; 041 } 042 043 /** 044 * Closes stream associated with current thread. 045 * 046 * @throws IOException 047 * if an error occurs 048 */ 049 @Override 050 public void close() throws IOException { 051 final OutputStream output = outputStreamThreadLocal.get(); 052 if (null != output) { 053 output.close(); 054 } 055 } 056 057 /** 058 * Flushes stream associated with current thread. 059 * 060 * @throws IOException 061 * if an error occurs 062 */ 063 @Override 064 public void flush() throws IOException { 065 @SuppressWarnings("resource") 066 final OutputStream output = outputStreamThreadLocal.get(); 067 if (null != output) { 068 output.flush(); 069 } 070 } 071 072 /** 073 * Writes byte to stream associated with current thread. 074 * 075 * @param ch 076 * the byte to write to stream 077 * @throws IOException 078 * if an error occurs 079 */ 080 @Override 081 public void write(final int ch) throws IOException { 082 @SuppressWarnings("resource") 083 final OutputStream output = outputStreamThreadLocal.get(); 084 if (null != output) { 085 output.write(ch); 086 } 087 } 088}