Package org.springframework.data.hadoop.store.input

Source Code of org.springframework.data.hadoop.store.input.TextSequenceFileReader

/*
* 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;
  }


}
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