com.marklogic.mapreduce.examples.LinkCountInDoc 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.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.util.GenericOptionsParser;
import org.w3c.dom.Attr;
import org.w3c.dom.Element;
import org.xml.sax.SAXException;
import com.marklogic.mapreduce.MarkLogicNode;
import com.marklogic.mapreduce.NodeInputFormat;
import com.marklogic.mapreduce.NodeOutputFormat;
import com.marklogic.mapreduce.NodePath;
/**
* Count the number of occurrences of each link title in documents in
* MarkLogic Server, and save the link count as a child node of each
* referenced document. Use with the configuration file
* conf/marklogic-nodein-nodeout.xml.
*/
@SuppressWarnings("deprecation")
public class LinkCountInDoc {
public static class RefMapper
extends Mapper {
private final static IntWritable one = new IntWritable(1);
private Text refURI = new Text();
public void map(NodePath key, MarkLogicNode value, Context context)
throws IOException, InterruptedException {
if (value != null && value.get() != null) {
Attr title = (Attr)value.get();
String href = title.getValue();
refURI.set(href.trim());
context.write(refURI, one);
}
}
}
public static class IntSumReducer
extends Reducer {
private final static String TEMPLATE = "0 ";
private final static String ROOT_ELEMENT_NAME = "//wp:page";
private final static String BASE_URI_PARAM_NAME = "mapreduce.linkcount.baseuri";
private NodePath nodePath = new NodePath();
private Element element;
private MarkLogicNode result;
private String baseUri;
protected void setup(Context context)
throws IOException, InterruptedException {
try {
DocumentBuilder docBuilder =
DocumentBuilderFactory.newInstance().newDocumentBuilder();
InputStream sbis = new ByteArrayInputStream(TEMPLATE.getBytes());
element = docBuilder.parse(sbis).getDocumentElement();
result = new MarkLogicNode(element);
baseUri = context.getConfiguration().get(BASE_URI_PARAM_NAME);
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void reduce(Text key, Iterable values,
Context context
) throws IOException, InterruptedException {
int sum = 0;
if (isInvalidName(key)) {
return;
}
for (IntWritable val : values) {
sum += val.get();
}
StringBuilder buf = new StringBuilder();
buf.append(baseUri).append(key);
nodePath.setDocumentUri(buf.toString());
nodePath.setRelativePath(ROOT_ELEMENT_NAME);
element.setTextContent(Integer.toString(sum));
context.write(nodePath, result);
}
// exclude key that is invalid for a document URI
private boolean isInvalidName(Text key) {
String keyString = key.toString();
return keyString == null || keyString.isEmpty() ||
keyString.matches("( )*");
}
}
public static void main(String[] args) throws Exception {
Configuration conf = new Configuration();
if (args.length < 1) {
System.err.println("Usage: LinkCountInDoc configFile");
System.exit(2);
}
String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs();
Job job = Job.getInstance(conf, "link count in doc");
job.setJarByClass(LinkCountInDoc.class);
job.setInputFormatClass(NodeInputFormat.class);
job.setMapperClass(RefMapper.class);
job.setMapOutputKeyClass(Text.class);
job.setMapOutputValueClass(IntWritable.class);
job.setReducerClass(IntSumReducer.class);
job.setOutputFormatClass(NodeOutputFormat.class);
job.setOutputKeyClass(NodePath.class);
job.setOutputValueClass(MarkLogicNode.class);
conf = job.getConfiguration();
conf.addResource(otherArgs[0]);
System.exit(job.waitForCompletion(true) ? 0 : 1);
}
}