    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 *   https://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.commons.compress.compressors.deflate;
    020
    021import java.io.IOException;
    022import java.io.OutputStream;
    023import java.util.zip.Deflater;
    024import java.util.zip.DeflaterOutputStream;
    025
    026import org.apache.commons.compress.compressors.CompressorOutputStream;
    027
    028/**
    029 * Deflate compressor.
    030 *
    031 * <em>Calling flush()</em>
    032 * <p>
    033 * Calling {@link #flush()} flushes the encoder and calls {@code outputStream.flush()}. All buffered pending data will then be decompressible from the output
    034 * stream. Calling this function very often may increase the compressed file size a lot.
    035 * </p>
    036 *
    037 * @since 1.9
    038 */
    039public class DeflateCompressorOutputStream extends CompressorOutputStream<DeflaterOutputStream> {
    040    private final Deflater deflater;
    041
    042    /**
    043     * Creates a Deflate compressed output stream with the default parameters.
    044     *
    045     * @param outputStream the stream to wrap
    046     */
    047    public DeflateCompressorOutputStream(final OutputStream outputStream) {
    048        this(outputStream, new DeflateParameters());
    049    }
    050
    051    /**
    052     * Creates a Deflate compressed output stream with the specified parameters.
    053     *
    054     * @param outputStream the stream to wrap
    055     * @param parameters   the deflate parameters to apply
    056     */
    057    public DeflateCompressorOutputStream(final OutputStream outputStream, final DeflateParameters parameters) {
    058        this.deflater = new Deflater(parameters.getCompressionLevel(), !parameters.withZlibHeader());
    059        this.out = new DeflaterOutputStream(outputStream, deflater);
    060    }
    061
    062    @Override
    063    public void close() throws IOException {
    064        try {
    065            super.close();
    066        } finally {
    067            deflater.end();
    068        }
    069    }
    070
    071    /**
    072     * Finishes compression without closing the underlying stream.
    073     * <p>
    074     * No more data can be written to this stream after finishing.
    075     * </p>
    076     *
    077     * @throws IOException on error
    078     */
    079    @Override
    080    @SuppressWarnings("resource") // instance variable access
    081    public void finish() throws IOException {
    082        out().finish();
    083        super.finish();
    084    }
    085
    086    /**
    087     * Flushes the encoder and calls {@code outputStream.flush()}. All buffered pending data will then be decompressible from the output stream. Calling this
    088     * function very often may increase the compressed file size a lot.
    089     */
    090    @Override
    091    public void flush() throws IOException {
    092        out.flush();
    093    }
    094
    095    @Override
    096    public void write(final byte[] buf, final int off, final int len) throws IOException {
    097        out.write(buf, off, len);
    098    }
    099
    100}