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.input; 018 019import static org.apache.commons.io.IOUtils.EOF; 020 021import java.io.IOException; 022import java.io.InputStream; 023 024import org.apache.commons.io.IOUtils; 025 026/** 027 * Data written to this stream is forwarded to a stream that has been associated with this thread. 028 */ 029public class DemuxInputStream extends InputStream { 030 private final InheritableThreadLocal<InputStream> inputStreamLocal = new InheritableThreadLocal<>(); 031 032 /** 033 * Binds the specified stream to the current thread. 034 * 035 * @param input the stream to bind 036 * @return the InputStream that was previously active 037 */ 038 public InputStream bindStream(final InputStream input) { 039 final InputStream oldValue = inputStreamLocal.get(); 040 inputStreamLocal.set(input); 041 return oldValue; 042 } 043 044 /** 045 * Closes stream associated with current thread. 046 * 047 * @throws IOException if an error occurs 048 */ 049 @SuppressWarnings("resource") // we actually close the stream here 050 @Override 051 public void close() throws IOException { 052 IOUtils.close(inputStreamLocal.get()); 053 } 054 055 /** 056 * Reads byte from stream associated with current thread. 057 * 058 * @return the byte read from stream 059 * @throws IOException if an error occurs 060 */ 061 @SuppressWarnings("resource") 062 @Override 063 public int read() throws IOException { 064 final InputStream inputStream = inputStreamLocal.get(); 065 if (null != inputStream) { 066 return inputStream.read(); 067 } 068 return EOF; 069 } 070}