[120] | 1 | /** |
---|
| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
---|
| 3 | * or more contributor license agreements. See the NOTICE file |
---|
| 4 | * distributed with this work for additional information |
---|
| 5 | * regarding copyright ownership. The ASF licenses this file |
---|
| 6 | * to you under the Apache License, Version 2.0 (the |
---|
| 7 | * "License"); you may not use this file except in compliance |
---|
| 8 | * with the License. You may obtain a copy of the License at |
---|
| 9 | * |
---|
| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
---|
| 11 | * |
---|
| 12 | * Unless required by applicable law or agreed to in writing, software |
---|
| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
---|
| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
---|
| 15 | * See the License for the specific language governing permissions and |
---|
| 16 | * limitations under the License. |
---|
| 17 | */ |
---|
| 18 | |
---|
| 19 | package org.apache.hadoop.mapreduce.lib.input; |
---|
| 20 | |
---|
| 21 | import java.io.IOException; |
---|
| 22 | |
---|
| 23 | |
---|
| 24 | import org.apache.hadoop.conf.Configuration; |
---|
| 25 | import org.apache.hadoop.fs.FileSystem; |
---|
| 26 | import org.apache.hadoop.fs.Path; |
---|
| 27 | import org.apache.hadoop.io.*; |
---|
| 28 | import org.apache.hadoop.mapreduce.InputSplit; |
---|
| 29 | import org.apache.hadoop.mapreduce.RecordReader; |
---|
| 30 | import org.apache.hadoop.mapreduce.TaskAttemptContext; |
---|
| 31 | |
---|
| 32 | /** An {@link RecordReader} for {@link SequenceFile}s. */ |
---|
| 33 | public class SequenceFileRecordReader<K, V> extends RecordReader<K, V> { |
---|
| 34 | private SequenceFile.Reader in; |
---|
| 35 | private long start; |
---|
| 36 | private long end; |
---|
| 37 | private boolean more = true; |
---|
| 38 | private K key = null; |
---|
| 39 | private V value = null; |
---|
| 40 | protected Configuration conf; |
---|
| 41 | |
---|
| 42 | @Override |
---|
| 43 | public void initialize(InputSplit split, |
---|
| 44 | TaskAttemptContext context |
---|
| 45 | ) throws IOException, InterruptedException { |
---|
| 46 | FileSplit fileSplit = (FileSplit) split; |
---|
| 47 | conf = context.getConfiguration(); |
---|
| 48 | Path path = fileSplit.getPath(); |
---|
| 49 | FileSystem fs = path.getFileSystem(conf); |
---|
| 50 | this.in = new SequenceFile.Reader(fs, path, conf); |
---|
| 51 | this.end = fileSplit.getStart() + fileSplit.getLength(); |
---|
| 52 | |
---|
| 53 | if (fileSplit.getStart() > in.getPosition()) { |
---|
| 54 | in.sync(fileSplit.getStart()); // sync to start |
---|
| 55 | } |
---|
| 56 | |
---|
| 57 | this.start = in.getPosition(); |
---|
| 58 | more = start < end; |
---|
| 59 | } |
---|
| 60 | |
---|
| 61 | @Override |
---|
| 62 | @SuppressWarnings("unchecked") |
---|
| 63 | public boolean nextKeyValue() throws IOException, InterruptedException { |
---|
| 64 | if (!more) { |
---|
| 65 | return false; |
---|
| 66 | } |
---|
| 67 | long pos = in.getPosition(); |
---|
| 68 | key = (K) in.next(key); |
---|
| 69 | if (key == null || (pos >= end && in.syncSeen())) { |
---|
| 70 | more = false; |
---|
| 71 | key = null; |
---|
| 72 | value = null; |
---|
| 73 | } else { |
---|
| 74 | value = (V) in.getCurrentValue(value); |
---|
| 75 | } |
---|
| 76 | return more; |
---|
| 77 | } |
---|
| 78 | |
---|
| 79 | @Override |
---|
| 80 | public K getCurrentKey() { |
---|
| 81 | return key; |
---|
| 82 | } |
---|
| 83 | |
---|
| 84 | @Override |
---|
| 85 | public V getCurrentValue() { |
---|
| 86 | return value; |
---|
| 87 | } |
---|
| 88 | |
---|
| 89 | /** |
---|
| 90 | * Return the progress within the input split |
---|
| 91 | * @return 0.0 to 1.0 of the input byte range |
---|
| 92 | */ |
---|
| 93 | public float getProgress() throws IOException { |
---|
| 94 | if (end == start) { |
---|
| 95 | return 0.0f; |
---|
| 96 | } else { |
---|
| 97 | return Math.min(1.0f, (in.getPosition() - start) / (float)(end - start)); |
---|
| 98 | } |
---|
| 99 | } |
---|
| 100 | |
---|
| 101 | public synchronized void close() throws IOException { in.close(); } |
---|
| 102 | |
---|
| 103 | } |
---|
| 104 | |
---|