| /** |
| * 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; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.util.ReflectionUtils; |
| |
| /** |
| * A global compressor/decompressor pool used to save and reuse |
| * (possibly native) compression/decompression codecs. |
| */ |
| public class CodecPool { |
| private static final Log LOG = LogFactory.getLog(CodecPool.class); |
| |
| /** |
| * A global compressor pool used to save the expensive |
| * construction/destruction of (possibly native) decompression codecs. |
| */ |
| private static final Map<Class<Compressor>, List<Compressor>> compressorPool = |
| new HashMap<Class<Compressor>, List<Compressor>>(); |
| |
| /** |
| * A global decompressor pool used to save the expensive |
| * construction/destruction of (possibly native) decompression codecs. |
| */ |
| private static final Map<Class<Decompressor>, List<Decompressor>> decompressorPool = |
| new HashMap<Class<Decompressor>, List<Decompressor>>(); |
| |
| private static <T> T borrow(Map<Class<T>, List<T>> pool, |
| Class<? extends T> codecClass) { |
| T codec = null; |
| |
| // Check if an appropriate codec is available |
| synchronized (pool) { |
| if (pool.containsKey(codecClass)) { |
| List<T> codecList = pool.get(codecClass); |
| |
| if (codecList != null) { |
| synchronized (codecList) { |
| if (!codecList.isEmpty()) { |
| codec = codecList.remove(codecList.size()-1); |
| } |
| } |
| } |
| } |
| } |
| |
| return codec; |
| } |
| |
| private static <T> void payback(Map<Class<T>, List<T>> pool, T codec) { |
| if (codec != null) { |
| Class<T> codecClass = ReflectionUtils.getClass(codec); |
| synchronized (pool) { |
| if (!pool.containsKey(codecClass)) { |
| pool.put(codecClass, new ArrayList<T>()); |
| } |
| |
| List<T> codecList = pool.get(codecClass); |
| synchronized (codecList) { |
| codecList.add(codec); |
| } |
| } |
| } |
| } |
| |
| /** |
| * Get a {@link Compressor} for the given {@link CompressionCodec} from the |
| * pool or a new one. |
| * |
| * @param codec the <code>CompressionCodec</code> for which to get the |
| * <code>Compressor</code> |
| * @param conf the <code>Configuration</code> object which contains confs for creating or reinit the compressor |
| * @return <code>Compressor</code> for the given |
| * <code>CompressionCodec</code> from the pool or a new one |
| */ |
| public static Compressor getCompressor(CompressionCodec codec, Configuration conf) { |
| Compressor compressor = borrow(compressorPool, codec.getCompressorType()); |
| if (compressor == null) { |
| compressor = codec.createCompressor(); |
| LOG.info("Got brand-new compressor"); |
| } else { |
| compressor.reinit(conf); |
| LOG.debug("Got recycled compressor"); |
| } |
| return compressor; |
| } |
| |
| public static Compressor getCompressor(CompressionCodec codec) { |
| return getCompressor(codec, null); |
| } |
| |
| /** |
| * Get a {@link Decompressor} for the given {@link CompressionCodec} from the |
| * pool or a new one. |
| * |
| * @param codec the <code>CompressionCodec</code> for which to get the |
| * <code>Decompressor</code> |
| * @return <code>Decompressor</code> for the given |
| * <code>CompressionCodec</code> the pool or a new one |
| */ |
| public static Decompressor getDecompressor(CompressionCodec codec) { |
| Decompressor decompressor = borrow(decompressorPool, codec.getDecompressorType()); |
| if (decompressor == null) { |
| decompressor = codec.createDecompressor(); |
| LOG.info("Got brand-new decompressor"); |
| } else { |
| LOG.debug("Got recycled decompressor"); |
| } |
| return decompressor; |
| } |
| |
| /** |
| * Return the {@link Compressor} to the pool. |
| * |
| * @param compressor the <code>Compressor</code> to be returned to the pool |
| */ |
| public static void returnCompressor(Compressor compressor) { |
| if (compressor == null) { |
| return; |
| } |
| // if the compressor can't be reused, don't pool it. |
| if (compressor.getClass().isAnnotationPresent(DoNotPool.class)) { |
| return; |
| } |
| compressor.reset(); |
| payback(compressorPool, compressor); |
| } |
| |
| /** |
| * Return the {@link Decompressor} to the pool. |
| * |
| * @param decompressor the <code>Decompressor</code> to be returned to the |
| * pool |
| */ |
| public static void returnDecompressor(Decompressor decompressor) { |
| if (decompressor == null) { |
| return; |
| } |
| // if the decompressor can't be reused, don't pool it. |
| if (decompressor.getClass().isAnnotationPresent(DoNotPool.class)) { |
| return; |
| } |
| decompressor.reset(); |
| payback(decompressorPool, decompressor); |
| } |
| } |