Java tutorial
/* * This file is part of Hadoop-Gpl-Compression. * * Hadoop-Gpl-Compression is free software: you can redistribute it * and/or modify it under the terms of the GNU General Public License * as published by the Free Software Foundation, either version 3 of * the License, or (at your option) any later version. * * Hadoop-Gpl-Compression is distributed in the hope that it will be * useful, but WITHOUT ANY WARRANTY; without even the implied warranty * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with Hadoop-Gpl-Compression. If not, see * <http://www.gnu.org/licenses/>. */ package com.hadoop.compression.lzo; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.Properties; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configurable; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.io.compress.BlockCompressorStream; import org.apache.hadoop.io.compress.BlockDecompressorStream; import org.apache.hadoop.io.compress.CompressionCodec; import org.apache.hadoop.io.compress.CompressionInputStream; import org.apache.hadoop.io.compress.CompressionOutputStream; import org.apache.hadoop.io.compress.Compressor; import org.apache.hadoop.io.compress.Decompressor; /** * A {@link org.apache.hadoop.io.compress.CompressionCodec} for a streaming * <b>lzo</b> compression/decompression pair. * http://www.oberhumer.com/opensource/lzo/ * */ public class LzoCodec implements Configurable, CompressionCodec { private static final Log LOG = LogFactory.getLog(LzoCodec.class.getName()); public static final String LZO_COMPRESSOR_KEY = "io.compression.codec.lzo.compressor"; public static final String LZO_DECOMPRESSOR_KEY = "io.compression.codec.lzo.decompressor"; public static final String LZO_COMPRESSION_LEVEL_KEY = "io.compression.codec.lzo.compression.level"; public static final String LZO_BUFFER_SIZE_KEY = "io.compression.codec.lzo.buffersize"; public static final int DEFAULT_LZO_BUFFER_SIZE = 256 * 1024; public static final int MAX_BLOCK_SIZE = 64 * 1024 * 1024; public static final int UNDEFINED_COMPRESSION_LEVEL = -999; // Constant from LzoCompressor.c private Configuration conf; @Override public void setConf(Configuration conf) { this.conf = conf; } @Override public Configuration getConf() { return conf; } private static boolean nativeLzoLoaded = false; static { if (GPLNativeCodeLoader.isNativeCodeLoaded()) { nativeLzoLoaded = LzoCompressor.isNativeLzoLoaded() && LzoDecompressor.isNativeLzoLoaded(); if (nativeLzoLoaded) { LOG.info("Successfully loaded & initialized native-lzo library [hadoop-lzo rev " + getRevisionHash() + "]"); } else { LOG.error("Failed to load/initialize native-lzo library"); } } else { LOG.error("Cannot load native-lzo without native-hadoop"); } } /** * Check if native-lzo library is loaded and initialized. * * @param conf configuration * @return <code>true</code> if native-lzo library is loaded and initialized; * else <code>false</code> */ public static boolean isNativeLzoLoaded(Configuration conf) { assert conf != null : "Configuration cannot be null!"; return nativeLzoLoaded && conf.getBoolean("hadoop.native.lib", true); } public static String getRevisionHash() { try { Properties p = new Properties(); p.load(LzoCodec.class.getResourceAsStream("/build.properties")); return p.getProperty("build_revision"); } catch (IOException e) { LOG.error("Could not find build properties file with revision hash"); return "UNKNOWN"; } } @Override public CompressionOutputStream createOutputStream(OutputStream out) throws IOException { return createOutputStream(out, createCompressor()); } @Override public CompressionOutputStream createOutputStream(OutputStream out, Compressor compressor) throws IOException { // Ensure native-lzo library is loaded & initialized if (!isNativeLzoLoaded(conf)) { throw new RuntimeException("native-lzo library not available"); } /** * <b>http://www.oberhumer.com/opensource/lzo/lzofaq.php</b> * * How much can my data expand during compression ? * ================================================ * LZO will expand incompressible data by a little amount. * I still haven't computed the exact values, but I suggest using * these formulas for a worst-case expansion calculation: * * Algorithm LZO1, LZO1A, LZO1B, LZO1C, LZO1F, LZO1X, LZO1Y, LZO1Z: * ---------------------------------------------------------------- * output_block_size = input_block_size + (input_block_size / 16) + 64 + 3 * * This is about 106% for a large block size. * * Algorithm LZO2A: * ---------------- * output_block_size = input_block_size + (input_block_size / 8) + 128 + 3 */ // Create the lzo output-stream LzoCompressor.CompressionStrategy strategy = getCompressionStrategy(conf); int bufferSize = getBufferSize(conf); int compressionOverhead = strategy.name().contains("LZO1") ? (bufferSize >> 4) + 64 + 3 : (bufferSize >> 3) + 128 + 3; return new BlockCompressorStream(out, compressor, bufferSize, compressionOverhead); } @Override public Class<? extends Compressor> getCompressorType() { // Ensure native-lzo library is loaded & initialized if (!isNativeLzoLoaded(conf)) { throw new RuntimeException("native-lzo library not available"); } return LzoCompressor.class; } @Override public Compressor createCompressor() { // Ensure native-lzo library is loaded & initialized assert conf != null : "Configuration cannot be null! You must call setConf() before creating a compressor."; if (!isNativeLzoLoaded(conf)) { throw new RuntimeException("native-lzo library not available"); } return new LzoCompressor(conf); } @Override public CompressionInputStream createInputStream(InputStream in) throws IOException { return createInputStream(in, createDecompressor()); } @Override public CompressionInputStream createInputStream(InputStream in, Decompressor decompressor) throws IOException { // Ensure native-lzo library is loaded & initialized if (!isNativeLzoLoaded(conf)) { throw new RuntimeException("native-lzo library not available"); } return new BlockDecompressorStream(in, decompressor, conf.getInt(LZO_BUFFER_SIZE_KEY, DEFAULT_LZO_BUFFER_SIZE)); } @Override public Class<? extends Decompressor> getDecompressorType() { // Ensure native-lzo library is loaded & initialized if (!isNativeLzoLoaded(conf)) { throw new RuntimeException("native-lzo library not available"); } return LzoDecompressor.class; } @Override public Decompressor createDecompressor() { // Ensure native-lzo library is loaded & initialized if (!isNativeLzoLoaded(conf)) { throw new RuntimeException("native-lzo library not available"); } return new LzoDecompressor(getDecompressionStrategy(conf), getBufferSize(conf)); } /** * Get the default filename extension for this kind of compression. * @return the extension including the '.' */ @Override public String getDefaultExtension() { return ".lzo_deflate"; } static LzoCompressor.CompressionStrategy getCompressionStrategy(Configuration conf) { assert conf != null : "Configuration cannot be null!"; return LzoCompressor.CompressionStrategy .valueOf(conf.get(LZO_COMPRESSOR_KEY, LzoCompressor.CompressionStrategy.LZO1X_1.name())); } static LzoDecompressor.CompressionStrategy getDecompressionStrategy(Configuration conf) { assert conf != null : "Configuration cannot be null!"; return LzoDecompressor.CompressionStrategy .valueOf(conf.get(LZO_DECOMPRESSOR_KEY, LzoDecompressor.CompressionStrategy.LZO1X.name())); } static int getCompressionLevel(Configuration conf) { assert conf != null : "Configuration cannot be null!"; return conf.getInt(LZO_COMPRESSION_LEVEL_KEY, UNDEFINED_COMPRESSION_LEVEL); } static int getBufferSize(Configuration conf) { assert conf != null : "Configuration cannot be null!"; return conf.getInt(LZO_BUFFER_SIZE_KEY, DEFAULT_LZO_BUFFER_SIZE); } public static void setCompressionStrategy(Configuration conf, LzoCompressor.CompressionStrategy strategy) { assert conf != null : "Configuration cannot be null!"; conf.set(LZO_COMPRESSOR_KEY, strategy.name()); } public static void setDecompressionStrategy(Configuration conf, LzoDecompressor.CompressionStrategy strategy) { assert conf != null : "Configuration cannot be null!"; conf.set(LZO_DECOMPRESSOR_KEY, strategy.name()); } public static void setCompressionLevel(Configuration conf, int compressionLevel) { assert conf != null : "Configuration cannot be null!"; conf.setInt(LZO_COMPRESSION_LEVEL_KEY, compressionLevel); } public static void setBufferSize(Configuration conf, int bufferSize) { assert conf != null : "Configuration cannot be null!"; conf.setInt(LZO_BUFFER_SIZE_KEY, bufferSize); } }