Java tutorial
/* * 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 clustering.tf_idf; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.NullWritable; import org.apache.hadoop.mapreduce.Reducer; import java.io.IOException; /** * Calculate the document number of the corpus. * * @author edwardlol * Created by edwardlol on 17-4-24. */ public class DocCntReducer extends Reducer<NullWritable, IntWritable, NullWritable, IntWritable> { //~ Instance fields -------------------------------------------------------- private IntWritable outputValue = new IntWritable(); private int counter = 0; //~ Methods ---------------------------------------------------------------- @Override protected void reduce(NullWritable key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException { for (IntWritable value : values) { this.counter += value.get(); } this.outputValue.set(this.counter); context.write(NullWritable.get(), this.outputValue); } } // End DocCntReducer.java