Java tutorial
/** * 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.oozie.action.hadoop; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.mapred.Mapper; import org.apache.hadoop.mapred.OutputCollector; import org.apache.hadoop.mapred.Reporter; import org.apache.hadoop.mapred.JobConf; import org.apache.hadoop.mapred.Reducer; import java.io.IOException; import java.util.Iterator; public class MapperReducerForTest implements Mapper, Reducer { public static final String GROUP = "g"; public static final String NAME = "c"; /** * If specified in the job conf, the mapper will write out the job.xml file here. */ public static final String JOB_XML_OUTPUT_LOCATION = "oozie.job.xml.output.location"; public static void main(String[] args) { System.out.println("hello!"); } @Override public void configure(JobConf jobConf) { try { String loc = jobConf.get(JOB_XML_OUTPUT_LOCATION); if (loc != null) { Path p = new Path(loc); FileSystem fs = p.getFileSystem(jobConf); if (!fs.exists(p)) { FSDataOutputStream out = fs.create(p); try { jobConf.writeXml(out); } finally { out.close(); } } } } catch (IOException ioe) { ioe.printStackTrace(); } } public void close() throws IOException { } @SuppressWarnings("unchecked") public void map(Object key, Object value, OutputCollector collector, Reporter reporter) throws IOException { collector.collect(key, value); reporter.incrCounter(GROUP, NAME, 5l); } @SuppressWarnings("unchecked") public void reduce(Object key, Iterator values, OutputCollector collector, Reporter reporter) throws IOException { while (values.hasNext()) { collector.collect(key, values.next()); } } }