hadoop SequenceFileAsTextRecordReader 源码
haddop SequenceFileAsTextRecordReader 代码
文件路径：/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/SequenceFileAsTextRecordReader.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.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
/**
* This class converts the input keys and values to their String forms by calling toString()
* method. This class to SequenceFileAsTextInputFormat class is as LineRecordReader
* class to TextInputFormat class.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class SequenceFileAsTextRecordReader
implements RecordReader<Text, Text> {
private final SequenceFileRecordReader<WritableComparable, Writable>
sequenceFileRecordReader;
private WritableComparable innerKey;
private Writable innerValue;
public SequenceFileAsTextRecordReader(Configuration conf, FileSplit split)
throws IOException {
sequenceFileRecordReader =
new SequenceFileRecordReader<WritableComparable, Writable>(conf, split);
innerKey = sequenceFileRecordReader.createKey();
innerValue = sequenceFileRecordReader.createValue();
}
public Text createKey() {
return new Text();
}
public Text createValue() {
return new Text();
}
/** Read key/value pair in a line. */
public synchronized boolean next(Text key, Text value) throws IOException {
Text tKey = key;
Text tValue = value;
if (!sequenceFileRecordReader.next(innerKey, innerValue)) {
return false;
}
tKey.set(innerKey.toString());
tValue.set(innerValue.toString());
return true;
}
public float getProgress() throws IOException {
return sequenceFileRecordReader.getProgress();
}
public synchronized long getPos() throws IOException {
return sequenceFileRecordReader.getPos();
}
public synchronized void close() throws IOException {
sequenceFileRecordReader.close();
}
}
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