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     */
017    package org.apache.commons.io.output;
018    
019    import java.io.IOException;
020    import java.io.OutputStream;
021    
022    /**
023     * Classic splitter of OutputStream. Named after the unix 'tee' 
024     * command. It allows a stream to be branched off so there 
025     * are now two streams.
026     *
027     * @version $Id: TeeOutputStream.java 1302056 2012-03-18 03:03:38Z ggregory $
028     */
029    public class TeeOutputStream extends ProxyOutputStream {
030    
031        /** the second OutputStream to write to */
032        protected OutputStream branch;
033    
034        /**
035         * Constructs a TeeOutputStream.
036         * @param out the main OutputStream
037         * @param branch the second OutputStream
038         */
039        public TeeOutputStream(OutputStream out, OutputStream branch) {
040            super(out);
041            this.branch = branch;
042        }
043    
044        /**
045         * Write the bytes to both streams.
046         * @param b the bytes to write
047         * @throws IOException if an I/O error occurs
048         */
049        @Override
050        public synchronized void write(byte[] b) throws IOException {
051            super.write(b);
052            this.branch.write(b);
053        }
054    
055        /**
056         * Write the specified bytes to both streams.
057         * @param b the bytes to write
058         * @param off The start offset
059         * @param len The number of bytes to write
060         * @throws IOException if an I/O error occurs
061         */
062        @Override
063        public synchronized void write(byte[] b, int off, int len) throws IOException {
064            super.write(b, off, len);
065            this.branch.write(b, off, len);
066        }
067    
068        /**
069         * Write a byte to both streams.
070         * @param b the byte to write
071         * @throws IOException if an I/O error occurs
072         */
073        @Override
074        public synchronized void write(int b) throws IOException {
075            super.write(b);
076            this.branch.write(b);
077        }
078    
079        /**
080         * Flushes both streams.
081         * @throws IOException if an I/O error occurs
082         */
083        @Override
084        public void flush() throws IOException {
085            super.flush();
086            this.branch.flush();
087        }
088    
089        /**
090         * Closes both output streams.
091         * 
092         * If closing the main output stream throws an exception, attempt to close the branch output stream.
093         * 
094         * If closing the main and branch output streams both throw exceptions, which exceptions is thrown by this method is
095         * currently unspecified and subject to change.
096         * 
097         * @throws IOException
098         *             if an I/O error occurs
099         */
100        @Override
101        public void close() throws IOException {
102            try {
103                super.close();
104            } finally {
105                this.branch.close();
106            }
107        }
108    
109    }