MapRunner.java
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上传日期:2018-01-08
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- /**
- * 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.mapred;
- import java.io.IOException;
- import org.apache.hadoop.util.ReflectionUtils;
- /** Default {@link MapRunnable} implementation.*/
- public class MapRunner<K1, V1, K2, V2>
- implements MapRunnable<K1, V1, K2, V2> {
-
- private Mapper<K1, V1, K2, V2> mapper;
- private boolean incrProcCount;
- @SuppressWarnings("unchecked")
- public void configure(JobConf job) {
- this.mapper = ReflectionUtils.newInstance(job.getMapperClass(), job);
- //increment processed counter only if skipping feature is enabled
- this.incrProcCount = SkipBadRecords.getMapperMaxSkipRecords(job)>0 &&
- SkipBadRecords.getAutoIncrMapperProcCount(job);
- }
- public void run(RecordReader<K1, V1> input, OutputCollector<K2, V2> output,
- Reporter reporter)
- throws IOException {
- try {
- // allocate key & value instances that are re-used for all entries
- K1 key = input.createKey();
- V1 value = input.createValue();
-
- while (input.next(key, value)) {
- // map pair to output
- mapper.map(key, value, output, reporter);
- if(incrProcCount) {
- reporter.incrCounter(SkipBadRecords.COUNTER_GROUP,
- SkipBadRecords.COUNTER_MAP_PROCESSED_RECORDS, 1);
- }
- }
- } finally {
- mapper.close();
- }
- }
- protected Mapper<K1, V1, K2, V2> getMapper() {
- return mapper;
- }
- }