| /** |
| * 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.mapreduce.lib.input; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.mapreduce.Mapper; |
| import org.apache.hadoop.util.ReflectionUtils; |
| |
| /** |
| * An {@link Mapper} that delegates behavior of paths to multiple other |
| * mappers. |
| * |
| * @see MultipleInputs#addInputPath(Job, Path, Class, Class) |
| */ |
| @InterfaceAudience.Private |
| @InterfaceStability.Unstable |
| public class DelegatingMapper<K1, V1, K2, V2> extends Mapper<K1, V1, K2, V2> { |
| |
| private Mapper<K1, V1, K2, V2> mapper; |
| |
| @SuppressWarnings("unchecked") |
| protected void setup(Context context) |
| throws IOException, InterruptedException { |
| // Find the Mapper from the TaggedInputSplit. |
| TaggedInputSplit inputSplit = (TaggedInputSplit) context.getInputSplit(); |
| mapper = (Mapper<K1, V1, K2, V2>) ReflectionUtils.newInstance(inputSplit |
| .getMapperClass(), context.getConfiguration()); |
| |
| } |
| |
| @SuppressWarnings("unchecked") |
| public void run(Context context) |
| throws IOException, InterruptedException { |
| setup(context); |
| mapper.run(context); |
| cleanup(context); |
| } |
| } |