[120] | 1 | /** |
---|
| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
---|
| 3 | * or more contributor license agreements. See the NOTICE file |
---|
| 4 | * distributed with this work for additional information |
---|
| 5 | * regarding copyright ownership. The ASF licenses this file |
---|
| 6 | * to you under the Apache License, Version 2.0 (the |
---|
| 7 | * "License"); you may not use this file except in compliance |
---|
| 8 | * with the License. You may obtain a copy of the License at |
---|
| 9 | * |
---|
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
---|
| 11 | * |
---|
| 12 | * Unless required by applicable law or agreed to in writing, software |
---|
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
---|
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
---|
| 15 | * See the License for the specific language governing permissions and |
---|
| 16 | * limitations under the License. |
---|
| 17 | */ |
---|
| 18 | |
---|
| 19 | package org.apache.hadoop.io.serializer; |
---|
| 20 | |
---|
| 21 | import java.util.ArrayList; |
---|
| 22 | import java.util.List; |
---|
| 23 | |
---|
| 24 | import org.apache.commons.logging.Log; |
---|
| 25 | import org.apache.commons.logging.LogFactory; |
---|
| 26 | import org.apache.hadoop.conf.Configuration; |
---|
| 27 | import org.apache.hadoop.conf.Configured; |
---|
| 28 | import org.apache.hadoop.util.ReflectionUtils; |
---|
| 29 | import org.apache.hadoop.util.StringUtils; |
---|
| 30 | |
---|
| 31 | /** |
---|
| 32 | * <p> |
---|
| 33 | * A factory for {@link Serialization}s. |
---|
| 34 | * </p> |
---|
| 35 | */ |
---|
| 36 | public class SerializationFactory extends Configured { |
---|
| 37 | |
---|
| 38 | private static final Log LOG = |
---|
| 39 | LogFactory.getLog(SerializationFactory.class.getName()); |
---|
| 40 | |
---|
| 41 | private List<Serialization<?>> serializations = new ArrayList<Serialization<?>>(); |
---|
| 42 | |
---|
| 43 | /** |
---|
| 44 | * <p> |
---|
| 45 | * Serializations are found by reading the <code>io.serializations</code> |
---|
| 46 | * property from <code>conf</code>, which is a comma-delimited list of |
---|
| 47 | * classnames. |
---|
| 48 | * </p> |
---|
| 49 | */ |
---|
| 50 | public SerializationFactory(Configuration conf) { |
---|
| 51 | super(conf); |
---|
| 52 | for (String serializerName : conf.getStrings("io.serializations", |
---|
| 53 | new String[]{"org.apache.hadoop.io.serializer.WritableSerialization"})) { |
---|
| 54 | add(conf, serializerName); |
---|
| 55 | } |
---|
| 56 | } |
---|
| 57 | |
---|
| 58 | @SuppressWarnings("unchecked") |
---|
| 59 | private void add(Configuration conf, String serializationName) { |
---|
| 60 | try { |
---|
| 61 | |
---|
| 62 | Class<? extends Serialization> serializionClass = |
---|
| 63 | (Class<? extends Serialization>) conf.getClassByName(serializationName); |
---|
| 64 | serializations.add((Serialization) |
---|
| 65 | ReflectionUtils.newInstance(serializionClass, getConf())); |
---|
| 66 | } catch (ClassNotFoundException e) { |
---|
| 67 | LOG.warn("Serilization class not found: " + |
---|
| 68 | StringUtils.stringifyException(e)); |
---|
| 69 | } |
---|
| 70 | } |
---|
| 71 | |
---|
| 72 | public <T> Serializer<T> getSerializer(Class<T> c) { |
---|
| 73 | return getSerialization(c).getSerializer(c); |
---|
| 74 | } |
---|
| 75 | |
---|
| 76 | public <T> Deserializer<T> getDeserializer(Class<T> c) { |
---|
| 77 | return getSerialization(c).getDeserializer(c); |
---|
| 78 | } |
---|
| 79 | |
---|
| 80 | @SuppressWarnings("unchecked") |
---|
| 81 | public <T> Serialization<T> getSerialization(Class<T> c) { |
---|
| 82 | for (Serialization serialization : serializations) { |
---|
| 83 | if (serialization.accept(c)) { |
---|
| 84 | return (Serialization<T>) serialization; |
---|
| 85 | } |
---|
| 86 | } |
---|
| 87 | return null; |
---|
| 88 | } |
---|
| 89 | } |
---|