org.apache.hadoop.io.compress.zlib.ZlibFactory.java Source code

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Here is the source code for org.apache.hadoop.io.compress.zlib.ZlibFactory.java

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/*
 * 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.hadoop.io.compress.zlib;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.compress.Compressor;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.hadoop.io.compress.DirectDecompressor;
import org.apache.hadoop.io.compress.zlib.ZlibCompressor.CompressionLevel;
import org.apache.hadoop.io.compress.zlib.ZlibCompressor.CompressionStrategy;
import org.apache.hadoop.util.NativeCodeLoader;

import com.google.common.annotations.VisibleForTesting;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A collection of factories to create the right 
 * zlib/gzip compressor/decompressor instances.
 * 
 */
public class ZlibFactory {
    private static final Logger LOG = LoggerFactory.getLogger(ZlibFactory.class);

    private static boolean nativeZlibLoaded = false;

    static {
        loadNativeZLib();
    }

    /**
     * Load native library and set the flag whether to use native library. The
     * method is also used for reset the flag modified by setNativeZlibLoaded
     */
    @VisibleForTesting
    public static void loadNativeZLib() {
        if (NativeCodeLoader.isNativeCodeLoaded()) {
            nativeZlibLoaded = ZlibCompressor.isNativeZlibLoaded() && ZlibDecompressor.isNativeZlibLoaded();

            if (nativeZlibLoaded) {
                LOG.info("Successfully loaded & initialized native-zlib library");
            } else {
                LOG.warn("Failed to load/initialize native-zlib library");
            }
        }
    }

    /**
     * Set the flag whether to use native library. Used for testing non-native
     * libraries
     *
     */
    @VisibleForTesting
    public static void setNativeZlibLoaded(final boolean isLoaded) {
        ZlibFactory.nativeZlibLoaded = isLoaded;
    }

    /**
     * Check if native-zlib code is loaded & initialized correctly and 
     * can be loaded for this job.
     * 
     * @param conf configuration
     * @return <code>true</code> if native-zlib is loaded & initialized 
     *         and can be loaded for this job, else <code>false</code>
     */
    public static boolean isNativeZlibLoaded(Configuration conf) {
        return nativeZlibLoaded;
    }

    public static String getLibraryName() {
        return ZlibCompressor.getLibraryName();
    }

    /**
     * Return the appropriate type of the zlib compressor. 
     * 
     * @param conf configuration
     * @return the appropriate type of the zlib compressor.
     */
    public static Class<? extends Compressor> getZlibCompressorType(Configuration conf) {
        return (isNativeZlibLoaded(conf)) ? ZlibCompressor.class : BuiltInZlibDeflater.class;
    }

    /**
     * Return the appropriate implementation of the zlib compressor. 
     * 
     * @param conf configuration
     * @return the appropriate implementation of the zlib compressor.
     */
    public static Compressor getZlibCompressor(Configuration conf) {
        return (isNativeZlibLoaded(conf)) ? new ZlibCompressor(conf)
                : new BuiltInZlibDeflater(ZlibFactory.getCompressionLevel(conf).compressionLevel());
    }

    /**
     * Return the appropriate type of the zlib decompressor. 
     * 
     * @param conf configuration
     * @return the appropriate type of the zlib decompressor.
     */
    public static Class<? extends Decompressor> getZlibDecompressorType(Configuration conf) {
        return (isNativeZlibLoaded(conf)) ? ZlibDecompressor.class : BuiltInZlibInflater.class;
    }

    /**
     * Return the appropriate implementation of the zlib decompressor. 
     * 
     * @param conf configuration
     * @return the appropriate implementation of the zlib decompressor.
     */
    public static Decompressor getZlibDecompressor(Configuration conf) {
        return (isNativeZlibLoaded(conf)) ? new ZlibDecompressor() : new BuiltInZlibInflater();
    }

    /**
     * Return the appropriate implementation of the zlib direct decompressor. 
     * 
     * @param conf configuration
     * @return the appropriate implementation of the zlib decompressor.
     */
    public static DirectDecompressor getZlibDirectDecompressor(Configuration conf) {
        return (isNativeZlibLoaded(conf)) ? new ZlibDecompressor.ZlibDirectDecompressor() : null;
    }

    public static void setCompressionStrategy(Configuration conf, CompressionStrategy strategy) {
        conf.setEnum("zlib.compress.strategy", strategy);
    }

    public static CompressionStrategy getCompressionStrategy(Configuration conf) {
        return conf.getEnum("zlib.compress.strategy", CompressionStrategy.DEFAULT_STRATEGY);
    }

    public static void setCompressionLevel(Configuration conf, CompressionLevel level) {
        conf.setEnum("zlib.compress.level", level);
    }

    public static CompressionLevel getCompressionLevel(Configuration conf) {
        return conf.getEnum("zlib.compress.level", CompressionLevel.DEFAULT_COMPRESSION);
    }

}