hadoop MapRunner 源码
haddop MapRunner 代码
文件路径：/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/MapRunner.java
/**
* 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.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.util.ReflectionUtils;
/** Default {@link MapRunnable} implementation.*/
@InterfaceAudience.Public
@InterfaceStability.Stable
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;
}
}
相关信息
相关文章
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
8、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦