    001    // Copyright 2012 The Apache Software Foundation
    002    //
    003    // Licensed under the Apache License, Version 2.0 (the "License");
    004    // you may not use this file except in compliance with the License.
    005    // You may obtain a copy of the License at
    006    //
    007    //     http://www.apache.org/licenses/LICENSE-2.0
    008    //
    009    // Unless required by applicable law or agreed to in writing, software
    010    // distributed under the License is distributed on an "AS IS" BASIS,
    011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012    // See the License for the specific language governing permissions and
    013    // limitations under the License.
    014
    015    package org.apache.tapestry5.internal.util;
    016
    017    import java.io.IOException;
    018    import java.io.OutputStream;
    019
    020    /**
    021     * An output stream that acts like a "tee", copying all provided bytes to two output streams. This is used, for example,
    022     * to accumulate a hash of content even as it is being written.
    023     *
    024     * @since 5.3.5
    025     */
    026    public class TeeOutputStream extends OutputStream
    027    {
    028        private final OutputStream left, right;
    029
    030        public TeeOutputStream(OutputStream left, OutputStream right)
    031        {
    032            assert left != null;
    033            assert right != null;
    034
    035            this.left = left;
    036            this.right = right;
    037        }
    038
    039        @Override
    040        public void write(int b) throws IOException
    041        {
    042            left.write(b);
    043            right.write(b);
    044        }
    045
    046        @Override
    047        public void write(byte[] b) throws IOException
    048        {
    049            left.write(b);
    050            right.write(b);
    051        }
    052
    053        @Override
    054        public void write(byte[] b, int off, int len) throws IOException
    055        {
    056            left.write(b, off, len);
    057            right.write(b, off, len);
    058        }
    059
    060        @Override
    061        public void flush() throws IOException
    062        {
    063            left.flush();
    064            right.flush();
    065        }
    066
    067        @Override
    068        public void close() throws IOException
    069        {
    070            left.close();
    071            right.close();
    072        }
    073    }