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.rya.prospector.mr; import java.io.IOException; import java.util.Calendar; import java.util.Date; import java.util.Map; import org.apache.commons.lang.time.DateUtils; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.io.LongWritable; import org.apache.hadoop.mapreduce.Reducer; import org.apache.rya.prospector.domain.IntermediateProspect; import org.apache.rya.prospector.plans.IndexWorkPlan; import org.apache.rya.prospector.plans.IndexWorkPlanManager; import org.apache.rya.prospector.plans.impl.ServicesBackedIndexWorkPlanManager; import org.apache.rya.prospector.utils.ProspectorUtils; /** * Reduces the {@link IntermediateProspect} counts into their final values and * writes them to their final storage location during the Reduce step of the * Hadoop Map Reduce framework. */ public class ProspectorReducer extends Reducer<IntermediateProspect, LongWritable, IntermediateProspect, LongWritable> { private Date truncatedDate; private final IndexWorkPlanManager manager = new ServicesBackedIndexWorkPlanManager(); private Map<String, IndexWorkPlan> plans; @Override public void setup(Context context) throws IOException, InterruptedException { super.setup(context); final Configuration conf = context.getConfiguration(); final long now = conf.getLong("DATE", System.currentTimeMillis()); truncatedDate = DateUtils.truncate(new Date(now), Calendar.MINUTE); this.plans = ProspectorUtils.planMap(manager.getPlans()); } @Override protected void reduce(IntermediateProspect prospect, Iterable<LongWritable> values, Context context) throws IOException, InterruptedException { final IndexWorkPlan plan = plans.get(prospect.getIndex()); if (plan != null) { plan.reduce(prospect, values, truncatedDate, context); } } }