/**
* 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.examples;
import java.io.IOException;
import java.util.*;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.conf.Configured;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.BytesWritable;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.mapred.join.*;
import org.apache.hadoop.mapred.lib.IdentityMapper;
import org.apache.hadoop.mapred.lib.IdentityReducer;
import org.apache.hadoop.util.Tool;
import org.apache.hadoop.util.ToolRunner;
/**
* This is the trivial map/reduce program that does absolutely nothing
* other than use the framework to fragment and sort the input values.
*
* To run: bin/hadoop jar build/hadoop-examples.jar join
* [-m <i>maps</i>] [-r <i>reduces</i>]
* [-inFormat <i>input format class</i>]
* [-outFormat <i>output format class</i>]
* [-outKey <i>output key class</i>]
* [-outValue <i>output value class</i>]
* [-joinOp <inner|outer|override>]
* [<i>in-dir</i>]* <i>in-dir</i> <i>out-dir</i>
*/
public class Join extends Configured implements Tool {
static int printUsage() {
System.out.println("join [-m <maps>] [-r <reduces>] " +
"[-inFormat <input format class>] " +
"[-outFormat <output format class>] " +
"[-outKey <output key class>] " +
"[-outValue <output value class>] " +
"[-joinOp <inner|outer|override>] " +
"[input]* <input> <output>");
ToolRunner.printGenericCommandUsage(System.out);
return -1;
}
/**
* The main driver for sort program.
* Invoke this method to submit the map/reduce job.
* @throws IOException When there is communication problems with the
* job tracker.
*/
public int run(String[] args) throws Exception {
JobConf jobConf = new JobConf(getConf(), Sort.class);
jobConf.setJobName("join");
jobConf.setMapperClass(IdentityMapper.class);
jobConf.setReducerClass(IdentityReducer.class);
JobClient client = new JobClient(jobConf);
ClusterStatus cluster = client.getClusterStatus();
int num_maps = cluster.getTaskTrackers() *
jobConf.getInt("test.sort.maps_per_host", 10);
int num_reduces = (int) (cluster.getMaxReduceTasks() * 0.9);
String sort_reduces = jobConf.get("test.sort.reduces_per_host");
if (sort_reduces != null) {
num_reduces = cluster.getTaskTrackers() *
Integer.parseInt(sort_reduces);
}
Class<? extends InputFormat> inputFormatClass =
SequenceFileInputFormat.class;
Class<? extends OutputFormat> outputFormatClass =
SequenceFileOutputFormat.class;
Class<? extends WritableComparable> outputKeyClass = BytesWritable.class;
Class<? extends Writable> outputValueClass = TupleWritable.class;
String op = "inner";
List<String> otherArgs = new ArrayList<String>();
for(int i=0; i < args.length; ++i) {
try {
if ("-m".equals(args[i])) {
num_maps = Integer.parseInt(args[++i]);
} else if ("-r".equals(args[i])) {
num_reduces = Integer.parseInt(args[++i]);
} else if ("-inFormat".equals(args[i])) {
inputFormatClass =
Class.forName(args[++i]).asSubclass(InputFormat.class);
} else if ("-outFormat".equals(args[i])) {
outputFormatClass =
Class.forName(args[++i]).asSubclass(OutputFormat.class);
} else if ("-outKey".equals(args[i])) {
outputKeyClass =
Class.forName(args[++i]).asSubclass(WritableComparable.class);
} else if ("-outValue".equals(args[i])) {
outputValueClass =
Class.forName(args[++i]).asSubclass(Writable.class);
} else if ("-joinOp".equals(args[i])) {
op = args[++i];
} else {
otherArgs.add(args[i]);
}
} catch (NumberFormatException except) {
System.out.println("ERROR: Integer expected instead of " + args[i]);
return printUsage();
} catch (ArrayIndexOutOfBoundsException except) {
System.out.println("ERROR: Required parameter missing from " +
args[i-1]);
return printUsage(); // exits
}
}
// Set user-supplied (possibly default) job configs
jobConf.setNumMapTasks(num_maps);
jobConf.setNumReduceTasks(num_reduces);
if (otherArgs.size() < 2) {
System.out.println("ERROR: Wrong number of parameters: ");
return printUsage();
}
FileOutputFormat.setOutputPath(jobConf,
new Path(otherArgs.remove(otherArgs.size() - 1)));
List<Path> plist = new ArrayList<Path>(otherArgs.size());
for (String s : otherArgs) {
plist.add(new Path(s));
}
jobConf.setInputFormat(CompositeInputFormat.class);
jobConf.set("mapred.join.expr", CompositeInputFormat.compose(
op, inputFormatClass, plist.toArray(new Path[0])));
jobConf.setOutputFormat(outputFormatClass);
jobConf.setOutputKeyClass(outputKeyClass);
jobConf.setOutputValueClass(outputValueClass);
Date startTime = new Date();
System.out.println("Job started: " + startTime);
JobClient.runJob(jobConf);
Date end_time = new Date();
System.out.println("Job ended: " + end_time);
System.out.println("The job took " +
(end_time.getTime() - startTime.getTime()) /1000 + " seconds.");
return 0;
}
public static void main(String[] args) throws Exception {
int res = ToolRunner.run(new Configuration(), new Join(), args);
System.exit(res);
}
}