/**
* 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.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.SequenceFile.CompressionType;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.DefaultCodec;
import org.apache.hadoop.util.Progressable;
import org.apache.hadoop.util.ReflectionUtils;
/**
* An {@link OutputFormat} that writes keys, values to
* {@link SequenceFile}s in binary(raw) format
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class SequenceFileAsBinaryOutputFormat
extends SequenceFileOutputFormat <BytesWritable,BytesWritable> {
/**
* Inner class used for appendRaw
*/
static protected class WritableValueBytes extends org.apache.hadoop.mapreduce
.lib.output.SequenceFileAsBinaryOutputFormat.WritableValueBytes {
public WritableValueBytes() {
super();
}
public WritableValueBytes(BytesWritable value) {
super(value);
}
}
/**
* Set the key class for the {@link SequenceFile}
* <p>This allows the user to specify the key class to be different
* from the actual class ({@link BytesWritable}) used for writing </p>
*
* @param conf the {@link JobConf} to modify
* @param theClass the SequenceFile output key class.
*/
static public void setSequenceFileOutputKeyClass(JobConf conf,
Class<?> theClass) {
conf.setClass(org.apache.hadoop.mapreduce.lib.output.
SequenceFileAsBinaryOutputFormat.KEY_CLASS, theClass, Object.class);
}
/**
* Set the value class for the {@link SequenceFile}
* <p>This allows the user to specify the value class to be different
* from the actual class ({@link BytesWritable}) used for writing </p>
*
* @param conf the {@link JobConf} to modify
* @param theClass the SequenceFile output key class.
*/
static public void setSequenceFileOutputValueClass(JobConf conf,
Class<?> theClass) {
conf.setClass(org.apache.hadoop.mapreduce.lib.output.
SequenceFileAsBinaryOutputFormat.VALUE_CLASS, theClass, Object.class);
}
/**
* Get the key class for the {@link SequenceFile}
*
* @return the key class of the {@link SequenceFile}
*/
static public Class<? extends WritableComparable> getSequenceFileOutputKeyClass(JobConf conf) {
return conf.getClass(org.apache.hadoop.mapreduce.lib.output.
SequenceFileAsBinaryOutputFormat.KEY_CLASS,
conf.getOutputKeyClass().asSubclass(WritableComparable.class),
WritableComparable.class);
}
/**
* Get the value class for the {@link SequenceFile}
*
* @return the value class of the {@link SequenceFile}
*/
static public Class<? extends Writable> getSequenceFileOutputValueClass(JobConf conf) {
return conf.getClass(org.apache.hadoop.mapreduce.lib.output.
SequenceFileAsBinaryOutputFormat.VALUE_CLASS,
conf.getOutputValueClass().asSubclass(Writable.class), Writable.class);
}
@Override
public RecordWriter <BytesWritable, BytesWritable>
getRecordWriter(FileSystem ignored, JobConf job,
String name, Progressable progress)
throws IOException {
// get the path of the temporary output file
Path file = FileOutputFormat.getTaskOutputPath(job, name);
FileSystem fs = file.getFileSystem(job);
CompressionCodec codec = null;
CompressionType compressionType = CompressionType.NONE;
if (getCompressOutput(job)) {
// find the kind of compression to do
compressionType = getOutputCompressionType(job);
// find the right codec
Class<? extends CompressionCodec> codecClass = getOutputCompressorClass(job,
DefaultCodec.class);
codec = ReflectionUtils.newInstance(codecClass, job);
}
final SequenceFile.Writer out =
SequenceFile.createWriter(fs, job, file,
getSequenceFileOutputKeyClass(job),
getSequenceFileOutputValueClass(job),
compressionType,
codec,
progress);
return new RecordWriter<BytesWritable, BytesWritable>() {
private WritableValueBytes wvaluebytes = new WritableValueBytes();
public void write(BytesWritable bkey, BytesWritable bvalue)
throws IOException {
wvaluebytes.reset(bvalue);
out.appendRaw(bkey.getBytes(), 0, bkey.getLength(), wvaluebytes);
wvaluebytes.reset(null);
}
public void close(Reporter reporter) throws IOException {
out.close();
}
};
}
@Override
public void checkOutputSpecs(FileSystem ignored, JobConf job)
throws IOException {
super.checkOutputSpecs(ignored, job);
if (getCompressOutput(job) &&
getOutputCompressionType(job) == CompressionType.RECORD ){
throw new InvalidJobConfException("SequenceFileAsBinaryOutputFormat "
+ "doesn't support Record Compression" );
}
}
}