| /** |
| * 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.mapreduce.lib.input; |
| |
| 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.*; |
| import org.apache.hadoop.mapreduce.InputSplit; |
| import org.apache.hadoop.mapreduce.RecordReader; |
| import org.apache.hadoop.mapreduce.TaskAttemptContext; |
| |
| /** An {@link RecordReader} for {@link SequenceFile}s. */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public class SequenceFileRecordReader<K, V> extends RecordReader<K, V> { |
| private SequenceFile.Reader in; |
| private long start; |
| private long end; |
| private boolean more = true; |
| private K key = null; |
| private V value = null; |
| protected Configuration conf; |
| |
| @Override |
| public void initialize(InputSplit split, |
| TaskAttemptContext context |
| ) throws IOException, InterruptedException { |
| FileSplit fileSplit = (FileSplit) split; |
| conf = context.getConfiguration(); |
| Path path = fileSplit.getPath(); |
| FileSystem fs = path.getFileSystem(conf); |
| this.in = new SequenceFile.Reader(fs, path, conf); |
| this.end = fileSplit.getStart() + fileSplit.getLength(); |
| |
| if (fileSplit.getStart() > in.getPosition()) { |
| in.sync(fileSplit.getStart()); // sync to start |
| } |
| |
| this.start = in.getPosition(); |
| more = start < end; |
| } |
| |
| @Override |
| @SuppressWarnings("unchecked") |
| public boolean nextKeyValue() throws IOException, InterruptedException { |
| if (!more) { |
| return false; |
| } |
| long pos = in.getPosition(); |
| key = (K) in.next(key); |
| if (key == null || (pos >= end && in.syncSeen())) { |
| more = false; |
| key = null; |
| value = null; |
| } else { |
| value = (V) in.getCurrentValue(value); |
| } |
| return more; |
| } |
| |
| @Override |
| public K getCurrentKey() { |
| return key; |
| } |
| |
| @Override |
| public V getCurrentValue() { |
| return value; |
| } |
| |
| /** |
| * 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, (in.getPosition() - start) / (float)(end - start)); |
| } |
| } |
| |
| public synchronized void close() throws IOException { in.close(); } |
| |
| } |
| |