1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.io.output; 18 19 import java.io.IOException; 20 import java.io.OutputStream; 21 22 import org.apache.commons.io.IOUtils; 23 24 /** 25 * Forwards data to a stream that has been associated with this thread. 26 */ 27 public class DemuxOutputStream extends OutputStream { 28 29 private final InheritableThreadLocal<OutputStream> outputStreamThreadLocal = new InheritableThreadLocal<>(); 30 31 /** 32 * Construct a new instance. 33 */ 34 public DemuxOutputStream() { 35 // empty 36 } 37 38 /** 39 * Binds the specified stream to the current thread. 40 * 41 * @param output 42 * the stream to bind 43 * @return the OutputStream that was previously active 44 */ 45 public OutputStream bindStream(final OutputStream output) { 46 final OutputStream stream = outputStreamThreadLocal.get(); 47 outputStreamThreadLocal.set(output); 48 return stream; 49 } 50 51 /** 52 * Closes stream associated with current thread. 53 * 54 * @throws IOException 55 * if an error occurs 56 */ 57 @SuppressWarnings("resource") // we actually close the stream here 58 @Override 59 public void close() throws IOException { 60 IOUtils.close(outputStreamThreadLocal.get()); 61 } 62 63 /** 64 * Flushes stream associated with current thread. 65 * 66 * @throws IOException 67 * if an error occurs 68 */ 69 @Override 70 public void flush() throws IOException { 71 @SuppressWarnings("resource") 72 final OutputStream output = outputStreamThreadLocal.get(); 73 if (null != output) { 74 output.flush(); 75 } 76 } 77 78 /** 79 * Writes byte to stream associated with current thread. 80 * 81 * @param ch 82 * the byte to write to stream 83 * @throws IOException 84 * if an error occurs 85 */ 86 @Override 87 public void write(final int ch) throws IOException { 88 @SuppressWarnings("resource") 89 final OutputStream output = outputStreamThreadLocal.get(); 90 if (null != output) { 91 output.write(ch); 92 } 93 } 94 }