com.marklogic.mapreduce.examples.LinkCountValue Maven / Gradle / Ivy
/*
* Copyright (c) 2019 MarkLogic Corporation
*
* Licensed 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 com.marklogic.mapreduce.examples;
import java.io.IOException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;
import org.apache.hadoop.util.GenericOptionsParser;
import com.marklogic.mapreduce.MarkLogicConstants;
import com.marklogic.mapreduce.ValueInputFormat;
/**
* Count the occurrences of each link title in documents stored in MarkLogic
* Server, then write the link count summary to HDFS. Use with the
* configuration file conf/marklogic-textin-textout.xml.
*/
public class LinkCountValue {
public static class RefMapper
extends Mapper {
private final static IntWritable one = new IntWritable(1);
private Text refURI = new Text();
public void map(LongWritable key, Text value, Context context)
throws IOException, InterruptedException {
refURI.set(value);
context.write(refURI, one);
}
}
public static class IntSumReducer
extends Reducer {
private IntWritable result = new IntWritable();
public void reduce(Text key, Iterable values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
for (IntWritable val : values) {
sum += val.get();
}
result.set(sum);
context.write(key, result);
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
if (args.length < 2) {
System.err.println("Usage: LinkCountValue configFile outputDir");
System.exit(2);
}
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
Job job = Job.getInstance(conf, "link count value");
job.setJarByClass(LinkCountValue.class);
job.setInputFormatClass(ValueInputFormat.class);
job.setMapperClass(RefMapper.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
job.setCombinerClass(IntSumReducer.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputFormatClass(TextOutputFormat.class);
job.setOutputKeyClass(Text.class);
job.setOutputValueClass(IntWritable.class);
FileOutputFormat.setOutputPath(job, new Path(args[1]));
conf = job.getConfiguration();
conf.addResource(otherArgs[0]);
conf.setClass(MarkLogicConstants.INPUT_VALUE_CLASS, Text.class,
Writable.class);
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}