hadoop NullOutputFormat 源码
haddop NullOutputFormat 代码
文件路径：/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/lib/output/NullOutputFormat.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.mapreduce.lib.output;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.OutputCommitter;
import org.apache.hadoop.mapreduce.OutputFormat;
import org.apache.hadoop.mapreduce.RecordWriter;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
/**
* Consume all outputs and put them in /dev/null.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class NullOutputFormat<K, V> extends OutputFormat<K, V> {
@Override
public RecordWriter<K, V>
getRecordWriter(TaskAttemptContext context) {
return new RecordWriter<K, V>(){
public void write(K key, V value) { }
public void close(TaskAttemptContext context) { }
};
}
@Override
public void checkOutputSpecs(JobContext context) { }
@Override
public OutputCommitter getOutputCommitter(TaskAttemptContext context) {
return new OutputCommitter() {
public void abortTask(TaskAttemptContext taskContext) { }
public void cleanupJob(JobContext jobContext) { }
public void commitTask(TaskAttemptContext taskContext) { }
public boolean needsTaskCommit(TaskAttemptContext taskContext) {
return false;
}
public void setupJob(JobContext jobContext) { }
public void setupTask(TaskAttemptContext taskContext) { }
@Override
@Deprecated
public boolean isRecoverySupported() {
return true;
}
@Override
public void recoverTask(TaskAttemptContext taskContext)
throws IOException {
// Nothing to do for recovering the task.
}
};
}
}
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