org.apache.hadoop.mapreduce.lib.output.NullOutputFormat.java Source code

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Here is the source code for org.apache.hadoop.mapreduce.lib.output.NullOutputFormat.java

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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.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.
            }
        };
    }
}