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.output;
018
019import java.io.IOException;
020import 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 */
028public class TeeOutputStream extends ProxyOutputStream {
029
030    /** the second OutputStream to write to */
031    protected OutputStream branch; //TODO consider making this private
032
033    /**
034     * Constructs a TeeOutputStream.
035     * @param out the main OutputStream
036     * @param branch the second OutputStream
037     */
038    public TeeOutputStream(final OutputStream out, final OutputStream branch) {
039        super(out);
040        this.branch = branch;
041    }
042
043    /**
044     * Write the bytes to both streams.
045     * @param b the bytes to write
046     * @throws IOException if an I/O error occurs
047     */
048    @Override
049    public synchronized void write(final byte[] b) throws IOException {
050        super.write(b);
051        this.branch.write(b);
052    }
053
054    /**
055     * Write the specified bytes to both streams.
056     * @param b the bytes to write
057     * @param off The start offset
058     * @param len The number of bytes to write
059     * @throws IOException if an I/O error occurs
060     */
061    @Override
062    public synchronized void write(final byte[] b, final int off, final int len) throws IOException {
063        super.write(b, off, len);
064        this.branch.write(b, off, len);
065    }
066
067    /**
068     * Write a byte to both streams.
069     * @param b the byte to write
070     * @throws IOException if an I/O error occurs
071     */
072    @Override
073    public synchronized void write(final int b) throws IOException {
074        super.write(b);
075        this.branch.write(b);
076    }
077
078    /**
079     * Flushes both streams.
080     * @throws IOException if an I/O error occurs
081     */
082    @Override
083    public void flush() throws IOException {
084        super.flush();
085        this.branch.flush();
086    }
087
088    /**
089     * Closes both output streams.
090     *
091     * If closing the main output stream throws an exception, attempt to close the branch output stream.
092     *
093     * If closing the main and branch output streams both throw exceptions, which exceptions is thrown by this method is
094     * currently unspecified and subject to change.
095     *
096     * @throws IOException
097     *             if an I/O error occurs
098     */
099    @Override
100    public void close() throws IOException {
101        try {
102            super.close();
103        } finally {
104            this.branch.close();
105        }
106    }
107
108}