| /** |
| * 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; |
| |
| import org.apache.hadoop.conf.*; |
| import org.apache.hadoop.util.ReflectionUtils; |
| import java.util.HashMap; |
| |
| /** Factories for non-public writables. Defining a factory permits {@link |
| * ObjectWritable} to be able to construct instances of non-public classes. */ |
| public class WritableFactories { |
| private static final HashMap<Class, WritableFactory> CLASS_TO_FACTORY = |
| new HashMap<Class, WritableFactory>(); |
| |
| private WritableFactories() {} // singleton |
| |
| /** Define a factory for a class. */ |
| public static synchronized void setFactory(Class c, WritableFactory factory) { |
| CLASS_TO_FACTORY.put(c, factory); |
| } |
| |
| /** Define a factory for a class. */ |
| public static synchronized WritableFactory getFactory(Class c) { |
| return CLASS_TO_FACTORY.get(c); |
| } |
| |
| /** Create a new instance of a class with a defined factory. */ |
| public static Writable newInstance(Class<? extends Writable> c, Configuration conf) { |
| WritableFactory factory = WritableFactories.getFactory(c); |
| if (factory != null) { |
| Writable result = factory.newInstance(); |
| if (result instanceof Configurable) { |
| ((Configurable) result).setConf(conf); |
| } |
| return result; |
| } else { |
| return ReflectionUtils.newInstance(c, conf); |
| } |
| } |
| |
| /** Create a new instance of a class with a defined factory. */ |
| public static Writable newInstance(Class<? extends Writable> c) { |
| return newInstance(c, null); |
| } |
| |
| } |
| |