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.input; 18 19 import static org.apache.commons.io.IOUtils.EOF; 20 21 import java.io.IOException; 22 import java.io.InputStream; 23 24 import org.apache.commons.io.IOUtils; 25 26 /** 27 * Data written to this stream is forwarded to a stream that has been associated with this thread. 28 */ 29 public class DemuxInputStream extends InputStream { 30 31 private final InheritableThreadLocal<InputStream> inputStreamLocal = new InheritableThreadLocal<>(); 32 33 /** 34 * Binds the specified stream to the current thread. 35 * 36 * @param input the stream to bind 37 * @return the InputStream that was previously active 38 */ bindStream(final InputStream input)39 public InputStream bindStream(final InputStream input) { 40 final InputStream oldValue = inputStreamLocal.get(); 41 inputStreamLocal.set(input); 42 return oldValue; 43 } 44 45 /** 46 * Closes stream associated with current thread. 47 * 48 * @throws IOException if an error occurs 49 */ 50 @SuppressWarnings("resource") // we actually close the stream here 51 @Override close()52 public void close() throws IOException { 53 IOUtils.close(inputStreamLocal.get()); 54 } 55 56 /** 57 * Reads byte from stream associated with current thread. 58 * 59 * @return the byte read from stream 60 * @throws IOException if an error occurs 61 */ 62 @SuppressWarnings("resource") 63 @Override read()64 public int read() throws IOException { 65 final InputStream inputStream = inputStreamLocal.get(); 66 if (null != inputStream) { 67 return inputStream.read(); 68 } 69 return EOF; 70 } 71 } 72