MapContext.java
上传用户:quxuerui
上传日期:2018-01-08
资源大小:41811k
文件大小:2k
- /**
- * 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;
- import java.io.IOException;
- import org.apache.hadoop.conf.Configuration;
- /**
- * The context that is given to the {@link Mapper}.
- * @param <KEYIN> the key input type to the Mapper
- * @param <VALUEIN> the value input type to the Mapper
- * @param <KEYOUT> the key output type from the Mapper
- * @param <VALUEOUT> the value output type from the Mapper
- */
- public class MapContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
- extends TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> {
- private RecordReader<KEYIN,VALUEIN> reader;
- private InputSplit split;
- public MapContext(Configuration conf, TaskAttemptID taskid,
- RecordReader<KEYIN,VALUEIN> reader,
- RecordWriter<KEYOUT,VALUEOUT> writer,
- OutputCommitter committer,
- StatusReporter reporter,
- InputSplit split) {
- super(conf, taskid, writer, committer, reporter);
- this.reader = reader;
- this.split = split;
- }
- /**
- * Get the input split for this map.
- */
- public InputSplit getInputSplit() {
- return split;
- }
- @Override
- public KEYIN getCurrentKey() throws IOException, InterruptedException {
- return reader.getCurrentKey();
- }
- @Override
- public VALUEIN getCurrentValue() throws IOException, InterruptedException {
- return reader.getCurrentValue();
- }
- @Override
- public boolean nextKeyValue() throws IOException, InterruptedException {
- return reader.nextKeyValue();
- }
- }
-