io.cdap.cdap.internal.app.runtime.batch.dataset.UnsupportedOutputFormat Maven / Gradle / Ivy
/*
* Copyright © 2015-2017 Cask Data, Inc.
*
* Licensed 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 io.cdap.cdap.internal.app.runtime.batch.dataset;
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;
import org.apache.hadoop.mapreduce.lib.output.NullOutputFormat;
/**
* OutputFormat that allows instantiation of the RecordWriter, but throws {@link UnsupportedOperationException}
* upon any attempts to write to it.
*
* All other operations, such as its OutputCommitter's operations, are no-ops.
*
* @param Type of key
* @param Type of value
*/
public class UnsupportedOutputFormat extends OutputFormat {
@Override
public RecordWriter getRecordWriter(TaskAttemptContext context) {
return new RecordWriter() {
@Override
public void write(K key, V value) {
throw new UnsupportedOperationException("Writing to output is not supported.");
}
@Override
public void close(TaskAttemptContext context) { }
};
}
@Override
public void checkOutputSpecs(JobContext context) { }
@Override
public OutputCommitter getOutputCommitter(TaskAttemptContext context) {
return new NullOutputFormat<>().getOutputCommitter(context);
}
}