| /** |
| * 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.conf.Configuration; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.io.*; |
| import org.apache.hadoop.util.ReflectionUtils; |
| |
| /** An {@link RecordReader} for {@link SequenceFile}s. */ |
| public class SequenceFileRecordReader<K, V> implements RecordReader<K, V> { |
| |
| private SequenceFile.Reader in; |
| private long start; |
| private long end; |
| private boolean more = true; |
| protected Configuration conf; |
| |
| public SequenceFileRecordReader(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(); |
| this.conf = conf; |
| |
| if (split.getStart() > in.getPosition()) |
| in.sync(split.getStart()); // sync to start |
| |
| this.start = in.getPosition(); |
| more = start < end; |
| } |
| |
| |
| /** The class of key that must be passed to {@link |
| * #next(Object, Object)}.. */ |
| public Class getKeyClass() { return in.getKeyClass(); } |
| |
| /** The class of value that must be passed to {@link |
| * #next(Object, Object)}.. */ |
| public Class getValueClass() { return in.getValueClass(); } |
| |
| @SuppressWarnings("unchecked") |
| public K createKey() { |
| return (K) ReflectionUtils.newInstance(getKeyClass(), conf); |
| } |
| |
| @SuppressWarnings("unchecked") |
| public V createValue() { |
| return (V) ReflectionUtils.newInstance(getValueClass(), conf); |
| } |
| |
| public synchronized boolean next(K key, V value) throws IOException { |
| if (!more) return false; |
| long pos = in.getPosition(); |
| boolean remaining = (in.next(key) != null); |
| if (remaining) { |
| getCurrentValue(value); |
| } |
| if (pos >= end && in.syncSeen()) { |
| more = false; |
| } else { |
| more = remaining; |
| } |
| return more; |
| } |
| |
| protected synchronized boolean next(K key) |
| throws IOException { |
| if (!more) return false; |
| long pos = in.getPosition(); |
| boolean remaining = (in.next(key) != null); |
| if (pos >= end && in.syncSeen()) { |
| more = false; |
| } else { |
| more = remaining; |
| } |
| return more; |
| } |
| |
| protected synchronized void getCurrentValue(V value) |
| throws IOException { |
| in.getCurrentValue(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 long getPos() throws IOException { |
| return in.getPosition(); |
| } |
| |
| protected synchronized void seek(long pos) throws IOException { |
| in.seek(pos); |
| } |
| public synchronized void close() throws IOException { in.close(); } |
| |
| } |
| |