| /** |
| * 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.gora.examples.mapreduce; |
| |
| import java.io.IOException; |
| |
| import org.apache.gora.mapreduce.GoraMapper; |
| import org.apache.gora.persistency.Persistent; |
| import org.apache.gora.query.Query; |
| import org.apache.gora.store.DataStore; |
| import org.apache.gora.store.DataStoreFactory; |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.conf.Configured; |
| import org.apache.hadoop.io.NullWritable; |
| import org.apache.hadoop.mapreduce.Job; |
| import org.apache.hadoop.mapreduce.lib.output.NullOutputFormat; |
| import org.apache.hadoop.util.Tool; |
| import org.apache.hadoop.util.ToolRunner; |
| import org.apache.gora.util.ClassLoadingUtils; |
| |
| /** |
| * Example Hadoop job to count the row of a gora {@link Query}. |
| */ |
| public class QueryCounter<K, T extends Persistent> extends Configured implements Tool { |
| |
| public static final String COUNTER_GROUP = "QueryCounter"; |
| public static final String ROWS = "ROWS"; |
| |
| public QueryCounter(Configuration conf) { |
| setConf(conf); |
| } |
| |
| public static class QueryCounterMapper<K, T extends Persistent> |
| extends GoraMapper<K, T |
| , NullWritable, NullWritable> { |
| |
| @Override |
| protected void map(K key, T value, |
| Context context) throws IOException ,InterruptedException { |
| |
| context.getCounter(COUNTER_GROUP, ROWS).increment(1L); |
| }; |
| } |
| |
| /** Returns the Query to count the results of. Subclasses can |
| * override this function to customize the query. |
| * @return the Query object to count the results of. |
| */ |
| public Query<K, T> getQuery(DataStore<K,T> dataStore) { |
| Query<K,T> query = dataStore.newQuery(); |
| return query; |
| } |
| |
| /** |
| * Creates and returns the {@link Job} for submitting to Hadoop mapreduce. |
| * @param dataStore |
| * @param query |
| * @return |
| * @throws IOException |
| */ |
| public Job createJob(DataStore<K,T> dataStore, Query<K,T> query) throws IOException { |
| Job job = new Job(getConf()); |
| |
| job.setJobName("QueryCounter"); |
| job.setNumReduceTasks(0); |
| job.setJarByClass(getClass()); |
| /* Mappers are initialized with GoraMapper.initMapper()*/ |
| GoraMapper.initMapperJob(job, query, dataStore, NullWritable.class |
| , NullWritable.class, QueryCounterMapper.class, true); |
| |
| job.setOutputFormatClass(NullOutputFormat.class); |
| return job; |
| } |
| |
| |
| /** |
| * Returns the number of results to the Query |
| */ |
| public long countQuery(DataStore<K,T> dataStore, Query<K,T> query) throws Exception { |
| Job job = createJob(dataStore, query); |
| job.waitForCompletion(true); |
| |
| return job.getCounters().findCounter(COUNTER_GROUP, ROWS).getValue(); |
| } |
| |
| /** |
| * Returns the number of results to the Query obtained by the |
| * {@link #getQuery(DataStore)} method. |
| */ |
| public long countQuery(DataStore<K,T> dataStore) throws Exception { |
| Query<K,T> query = getQuery(dataStore); |
| |
| Job job = createJob(dataStore, query); |
| job.waitForCompletion(true); |
| |
| return job.getCounters().findCounter(COUNTER_GROUP, ROWS).getValue(); |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public int run(String[] args) throws Exception { |
| |
| if(args.length < 2) { |
| System.err.println("Usage QueryCounter <keyClass> <persistentClass> [dataStoreClass]"); |
| return 1; |
| } |
| |
| Class<K> keyClass = (Class<K>) ClassLoadingUtils.loadClass(args[0]); |
| Class<T> persistentClass = (Class<T>) ClassLoadingUtils.loadClass(args[1]); |
| |
| DataStore<K,T> dataStore; |
| Configuration conf = new Configuration(); |
| |
| if(args.length > 2) { |
| Class<? extends DataStore<K,T>> dataStoreClass |
| = (Class<? extends DataStore<K, T>>) Class.forName(args[2]); |
| dataStore = DataStoreFactory.getDataStore(dataStoreClass, keyClass, persistentClass, conf); |
| } |
| else { |
| dataStore = DataStoreFactory.getDataStore(keyClass, persistentClass, conf); |
| } |
| |
| long results = countQuery(dataStore); |
| |
| System.out.println("Number of result to the query:" + results); |
| |
| return 0; |
| } |
| |
| |
| @SuppressWarnings("rawtypes") |
| public static void main(String[] args) throws Exception { |
| int ret = ToolRunner.run(new QueryCounter(new Configuration()), args); |
| System.exit(ret); |
| } |
| } |