com.gemstone.gemfire.cache.hdfs.internal.hoplog.mapred.AbstractGFRecordReader Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of gemfire-core Show documentation
SnappyData store based off Pivotal GemFireXD
The newest version!
/*
 * Copyright (c) 2010-2015 Pivotal Software, Inc. All rights reserved.
 *
 * 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. See accompanying
 * LICENSE file.
 */
package com.gemstone.gemfire.cache.hdfs.internal.hoplog.mapred;

import java.io.IOException;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.RecordReader;
import org.apache.hadoop.mapred.lib.CombineFileSplit;

import com.gemstone.gemfire.cache.hdfs.internal.PersistedEventImpl;
import com.gemstone.gemfire.cache.hdfs.internal.SortedHoplogPersistedEvent;
import com.gemstone.gemfire.cache.hdfs.internal.UnsortedHoplogPersistedEvent;
import com.gemstone.gemfire.cache.hdfs.internal.hoplog.mapreduce.GFKey;
import com.gemstone.gemfire.cache.hdfs.internal.hoplog.mapreduce.HDFSSplitIterator;

public class AbstractGFRecordReader
    extends
    com.gemstone.gemfire.cache.hdfs.internal.hoplog.mapreduce.AbstractGFRecordReader
    implements RecordReader {

  /**
   * Initializes instance of record reader using file split and job
   * configuration
   * 
   * @param split
   * @param conf
   * @throws IOException
   */
  public void initialize(CombineFileSplit split, JobConf conf) throws IOException {
    CombineFileSplit cSplit = (CombineFileSplit) split;
    Path[] path = cSplit.getPaths();
    long[] start = cSplit.getStartOffsets();
    long[] len = cSplit.getLengths();

    FileSystem fs = cSplit.getPath(0).getFileSystem(conf);
    this.splitIterator = HDFSSplitIterator.newInstance(fs, path, start, len, 0l, 0l);
  }

  @Override
  public boolean next(GFKey key, PersistedEventImpl value) throws IOException {
    /*
     * if there are more records in the hoplog, iterate to the next record. Set
     * key object as is. 
     */

    if (!super.hasNext()) {
      key.setKey(null);
      // TODO make value null;
      return false;
    }

    super.next();

    key.setKey(super.getKey().getKey());
    PersistedEventImpl usersValue = super.getValue();
    value.copy(usersValue);
    return true;
  }

  @Override
  public GFKey createKey() {
    return new GFKey();
  }

  @Override
  public PersistedEventImpl createValue() {
    if(this.isSequential) {
      return new UnsortedHoplogPersistedEvent();
    } else {
      return new SortedHoplogPersistedEvent();
    }
  }

  @Override
  public long getPos() throws IOException {
    // there is no efficient way to find the position of key in hoplog file.
    return 0;
  }

  @Override
  public void close() throws IOException {
    super.close();
  }

  @Override
  public float getProgress() throws IOException {
    return super.getProgressRatio();
  }
}