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 private final InheritableThreadLocal<OutputStream> outputStreamThreadLocal = new InheritableThreadLocal<>(); 29 30 /** 31 * Binds the specified stream to the current thread. 32 * 33 * @param output 34 * the stream to bind 35 * @return the OutputStream that was previously active 36 */ 37 public OutputStream bindStream(final OutputStream output) { 38 final OutputStream stream = outputStreamThreadLocal.get(); 39 outputStreamThreadLocal.set(output); 40 return stream; 41 } 42 43 /** 44 * Closes stream associated with current thread. 45 * 46 * @throws IOException 47 * if an error occurs 48 */ 49 @SuppressWarnings("resource") // we actually close the stream here 50 @Override 51 public void close() throws IOException { 52 IOUtils.close(outputStreamThreadLocal.get()); 53 } 54 55 /** 56 * Flushes stream associated with current thread. 57 * 58 * @throws IOException 59 * if an error occurs 60 */ 61 @Override 62 public void flush() throws IOException { 63 @SuppressWarnings("resource") 64 final OutputStream output = outputStreamThreadLocal.get(); 65 if (null != output) { 66 output.flush(); 67 } 68 } 69 70 /** 71 * Writes byte to stream associated with current thread. 72 * 73 * @param ch 74 * the byte to write to stream 75 * @throws IOException 76 * if an error occurs 77 */ 78 @Override 79 public void write(final int ch) throws IOException { 80 @SuppressWarnings("resource") 81 final OutputStream output = outputStreamThreadLocal.get(); 82 if (null != output) { 83 output.write(ch); 84 } 85 } 86 }