DeflateCompressorOutputStream.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.commons.compress.compressors.deflate;

import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;

import org.apache.commons.compress.compressors.CompressorOutputStream;

/**
 * Deflate compressor.
 *
 * <em>Calling flush()</em>
 * <p>
 * Calling {@link #flush()} flushes the encoder and calls {@code outputStream.flush()}. All buffered pending data will then be decompressible from the output
 * stream. Calling this function very often may increase the compressed file size a lot.
 * </p>
 *
 * @since 1.9
 */
public class DeflateCompressorOutputStream extends CompressorOutputStream<DeflaterOutputStream> {
    private final Deflater deflater;

    /**
     * Creates a Deflate compressed output stream with the default parameters.
     *
     * @param outputStream the stream to wrap
     */
    public DeflateCompressorOutputStream(final OutputStream outputStream) {
        this(outputStream, new DeflateParameters());
    }

    /**
     * Creates a Deflate compressed output stream with the specified parameters.
     *
     * @param outputStream the stream to wrap
     * @param parameters   the deflate parameters to apply
     */
    public DeflateCompressorOutputStream(final OutputStream outputStream, final DeflateParameters parameters) {
        super();
        this.deflater = new Deflater(parameters.getCompressionLevel(), !parameters.withZlibHeader());
        this.out = new DeflaterOutputStream(outputStream, deflater);
    }

    @Override
    public void close() throws IOException {
        try {
            out.close();
        } finally {
            deflater.end();
        }
    }

    /**
     * Finishes compression without closing the underlying stream.
     * <p>
     * No more data can be written to this stream after finishing.
     * </p>
     *
     * @throws IOException on error
     */
    @SuppressWarnings("resource") // instance variable access
    public void finish() throws IOException {
        out().finish();
    }

    /**
     * Flushes the encoder and calls {@code outputStream.flush()}. All buffered pending data will then be decompressible from the output stream. Calling this
     * function very often may increase the compressed file size a lot.
     */
    @Override
    public void flush() throws IOException {
        out.flush();
    }

    @Override
    public void write(final byte[] buf, final int off, final int len) throws IOException {
        out.write(buf, off, len);
    }

}