/*
* Copyright 2013 the original author or authors.
*
* 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 org.springframework.data.hadoop.store.input;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.SequenceFile.Reader;
import org.apache.hadoop.io.Text;
import org.springframework.data.hadoop.store.DataStoreReader;
import org.springframework.data.hadoop.store.codec.CodecInfo;
/**
* A {@code TextSequenceFileReader} is a {@code DataStoreReader} implementation
* able to read {@code String}s from a {@code SequenceFile}.
*
* @author Janne Valkealahti
*
*/
public class TextSequenceFileReader extends AbstractSequenceFileReader implements DataStoreReader<String> {
private Reader reader;
/**
* Instantiates a new text sequence file reader.
*
* @param configuration the hadoop configuration
* @param basePath the hdfs path
* @param codec the compression codec info
*/
public TextSequenceFileReader(Configuration configuration, Path basePath, CodecInfo codec) {
super(configuration, basePath, codec);
}
@Override
public void close() throws IOException {
reader.close();
}
@Override
public String read() throws IOException {
if (reader == null) {
reader = getInput();
}
Text k = new Text();
Text v = new Text();
reader.next(k, v);
byte[] value = v.getBytes();
return value != null && value.length > 0 ? new String(value) : null;
}
}