/** | |
* 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.contrib.index.mapred; | |
import java.io.IOException; | |
import java.util.Iterator; | |
import org.apache.commons.logging.Log; | |
import org.apache.commons.logging.LogFactory; | |
import org.apache.hadoop.contrib.index.lucene.ShardWriter; | |
import org.apache.hadoop.fs.FileSystem; | |
import org.apache.hadoop.fs.Path; | |
import org.apache.hadoop.io.Closeable; | |
import org.apache.hadoop.io.Text; | |
import org.apache.hadoop.io.Writable; | |
import org.apache.hadoop.io.WritableComparable; | |
import org.apache.hadoop.mapred.JobConf; | |
import org.apache.hadoop.mapred.MapReduceBase; | |
import org.apache.hadoop.mapred.OutputCollector; | |
import org.apache.hadoop.mapred.Reducer; | |
import org.apache.hadoop.mapred.Reporter; | |
/** | |
* This reducer applies to a shard the changes for it. A "new version" of | |
* a shard is created at the end of a reduce. It is important to note that | |
* the new version of the shard is not derived from scratch. By leveraging | |
* Lucene's update algorithm, the new version of each Lucene instance will | |
* share as many files as possible as the previous version. | |
*/ | |
public class IndexUpdateReducer extends MapReduceBase implements | |
Reducer<Shard, IntermediateForm, Shard, Text> { | |
static final Log LOG = LogFactory.getLog(IndexUpdateReducer.class); | |
static final Text DONE = new Text("done"); | |
/** | |
* Get the reduce output key class. | |
* @return the reduce output key class | |
*/ | |
public static Class<? extends WritableComparable> getOutputKeyClass() { | |
return Shard.class; | |
} | |
/** | |
* Get the reduce output value class. | |
* @return the reduce output value class | |
*/ | |
public static Class<? extends Writable> getOutputValueClass() { | |
return Text.class; | |
} | |
private IndexUpdateConfiguration iconf; | |
private String mapredTempDir; | |
/* (non-Javadoc) | |
* @see org.apache.hadoop.mapred.Reducer#reduce(java.lang.Object, java.util.Iterator, org.apache.hadoop.mapred.OutputCollector, org.apache.hadoop.mapred.Reporter) | |
*/ | |
public void reduce(Shard key, Iterator<IntermediateForm> values, | |
OutputCollector<Shard, Text> output, Reporter reporter) | |
throws IOException { | |
LOG.info("Construct a shard writer for " + key); | |
FileSystem fs = FileSystem.get(iconf.getConfiguration()); | |
String temp = | |
mapredTempDir + Path.SEPARATOR + "shard_" + System.currentTimeMillis(); | |
final ShardWriter writer = new ShardWriter(fs, key, temp, iconf); | |
// update the shard | |
while (values.hasNext()) { | |
IntermediateForm form = values.next(); | |
writer.process(form); | |
reporter.progress(); | |
} | |
// close the shard | |
final Reporter fReporter = reporter; | |
new Closeable() { | |
volatile boolean closed = false; | |
public void close() throws IOException { | |
// spawn a thread to give progress heartbeats | |
Thread prog = new Thread() { | |
public void run() { | |
while (!closed) { | |
try { | |
fReporter.setStatus("closing"); | |
Thread.sleep(1000); | |
} catch (InterruptedException e) { | |
continue; | |
} catch (Throwable e) { | |
return; | |
} | |
} | |
} | |
}; | |
try { | |
prog.start(); | |
if (writer != null) { | |
writer.close(); | |
} | |
} finally { | |
closed = true; | |
} | |
} | |
}.close(); | |
LOG.info("Closed the shard writer for " + key + ", writer = " + writer); | |
output.collect(key, DONE); | |
} | |
/* (non-Javadoc) | |
* @see org.apache.hadoop.mapred.MapReduceBase#configure(org.apache.hadoop.mapred.JobConf) | |
*/ | |
public void configure(JobConf job) { | |
iconf = new IndexUpdateConfiguration(job); | |
mapredTempDir = iconf.getMapredTempDir(); | |
mapredTempDir = Shard.normalizePath(mapredTempDir); | |
} | |
/* (non-Javadoc) | |
* @see org.apache.hadoop.mapred.MapReduceBase#close() | |
*/ | |
public void close() throws IOException { | |
} | |
} |