hadoop SequenceFileAsBinaryInputFormat 源码

  • 2022-10-20
  • 浏览 (142)

haddop SequenceFileAsBinaryInputFormat 代码

文件路径:/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/SequenceFileAsBinaryInputFormat.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.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.DataOutputBuffer;
import org.apache.hadoop.io.SequenceFile;

/**
 * InputFormat reading keys, values from SequenceFiles in binary (raw)
 * format.
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class SequenceFileAsBinaryInputFormat
    extends SequenceFileInputFormat<BytesWritable,BytesWritable> {

  public SequenceFileAsBinaryInputFormat() {
    super();
  }

  public RecordReader<BytesWritable,BytesWritable> getRecordReader(
      InputSplit split, JobConf job, Reporter reporter)
      throws IOException {
    return new SequenceFileAsBinaryRecordReader(job, (FileSplit)split);
  }

  /**
   * Read records from a SequenceFile as binary (raw) bytes.
   */
  public static class SequenceFileAsBinaryRecordReader
      implements RecordReader<BytesWritable,BytesWritable> {
    private SequenceFile.Reader in;
    private long start;
    private long end;
    private boolean done = false;
    private DataOutputBuffer buffer = new DataOutputBuffer();
    private SequenceFile.ValueBytes vbytes;

    public SequenceFileAsBinaryRecordReader(Configuration conf, FileSplit split)
        throws IOException {
      Path path = split.getPath();
      FileSystem fs = path.getFileSystem(conf);
      this.in = new SequenceFile.Reader(fs, path, conf);
      this.end = split.getStart() + split.getLength();
      if (split.getStart() > in.getPosition())
        in.sync(split.getStart());                  // sync to start
      this.start = in.getPosition();
      vbytes = in.createValueBytes();
      done = start >= end;
    }

    public BytesWritable createKey() {
      return new BytesWritable();
    }

    public BytesWritable createValue() {
      return new BytesWritable();
    }

    /**
     * Retrieve the name of the key class for this SequenceFile.
     * @see org.apache.hadoop.io.SequenceFile.Reader#getKeyClassName
     */
    public String getKeyClassName() {
      return in.getKeyClassName();
    }

    /**
     * Retrieve the name of the value class for this SequenceFile.
     * @see org.apache.hadoop.io.SequenceFile.Reader#getValueClassName
     */
    public String getValueClassName() {
      return in.getValueClassName();
    }

    /**
     * Read raw bytes from a SequenceFile.
     */
    public synchronized boolean next(BytesWritable key, BytesWritable val)
        throws IOException {
      if (done) return false;
      long pos = in.getPosition();
      boolean eof = -1 == in.nextRawKey(buffer);
      if (!eof) {
        key.set(buffer.getData(), 0, buffer.getLength());
        buffer.reset();
        in.nextRawValue(vbytes);
        vbytes.writeUncompressedBytes(buffer);
        val.set(buffer.getData(), 0, buffer.getLength());
        buffer.reset();
      }
      return !(done = (eof || (pos >= end && in.syncSeen())));
    }

    public long getPos() throws IOException {
      return in.getPosition();
    }

    public void close() throws IOException {
      in.close();
    }

    /**
     * Return the progress within the input split
     * @return 0.0 to 1.0 of the input byte range
     */
    public float getProgress() throws IOException {
      if (end == start) {
        return 0.0f;
      } else {
        return Math.min(1.0f, (float)((in.getPosition() - start) /
                                      (double)(end - start)));
      }
    }
  }
}

相关信息

hadoop 源码目录

相关文章

hadoop AMFeedback 源码

hadoop BackupStore 源码

hadoop BasicTypeSorterBase 源码

hadoop BufferSorter 源码

hadoop CleanupQueue 源码

hadoop Clock 源码

hadoop ClusterStatus 源码

hadoop Counters 源码

hadoop CumulativePeriodicStats 源码

hadoop DeprecatedQueueConfigurationParser 源码

0  赞