    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 * http://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.xz;
    020
    021import java.io.IOException;
    022import java.io.OutputStream;
    023
    024import org.apache.commons.compress.compressors.CompressorOutputStream;
    025import org.tukaani.xz.LZMA2Options;
    026import org.tukaani.xz.XZOutputStream;
    027
    028/**
    029 * XZ 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 1.4
    038 */
    039public class XZCompressorOutputStream extends CompressorOutputStream<XZOutputStream> {
    040
    041    /**
    042     * Creates a new XZ compressor using the default LZMA2 options. This is equivalent to {@code XZCompressorOutputStream(outputStream, 6)}.
    043     *
    044     * @param outputStream the stream to wrap
    045     * @throws IOException on error
    046     */
    047    @SuppressWarnings("resource") // Caller closes
    048    public XZCompressorOutputStream(final OutputStream outputStream) throws IOException {
    049        super(new XZOutputStream(outputStream, new LZMA2Options()));
    050    }
    051
    052    /**
    053     * Creates a new XZ compressor using the specified LZMA2 preset level.
    054     * <p>
    055     * The presets 0-3 are fast presets with medium compression. The presets 4-6 are fairly slow presets with high compression. The default preset is 6.
    056     * <p>
    057     * The presets 7-9 are like the preset 6 but use bigger dictionaries and have higher compressor and decompressor memory requirements. Unless the
    058     * uncompressed size of the file exceeds 8&nbsp;MiB, 16&nbsp;MiB, or 32&nbsp;MiB, it is waste of memory to use the presets 7, 8, or 9, respectively.
    059     *
    060     * @param outputStream the stream to wrap
    061     * @param preset       the preset
    062     * @throws IOException on error
    063     */
    064    @SuppressWarnings("resource") // Caller closes
    065    public XZCompressorOutputStream(final OutputStream outputStream, final int preset) throws IOException {
    066        super(new XZOutputStream(outputStream, new LZMA2Options(preset)));
    067    }
    068
    069    /**
    070     * Finishes compression without closing the underlying stream. No more data can be written to this stream after finishing.
    071     *
    072     * @throws IOException on error
    073     */
    074    @SuppressWarnings("resource") // instance variable access
    075    public void finish() throws IOException {
    076        out().finish();
    077    }
    078
    079    @Override
    080    public void write(final byte[] buf, final int off, final int len) throws IOException {
    081        out.write(buf, off, len);
    082    }
    083
    084}