content: /*
   * 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.spark.examples;
  
  import scala.Tuple2;
  import org.apache.spark.api.java.JavaPairRDD;
  import org.apache.spark.api.java.JavaRDD;
  import org.apache.spark.api.java.JavaSparkContext;
  import org.apache.spark.api.java.function.FlatMapFunction;
  import org.apache.spark.api.java.function.Function2;
  import org.apache.spark.api.java.function.PairFunction;
  
  import java.util.Arrays;
  import java.util.List;
  import java.util.regex.Pattern;
  
  public final class JavaWordCount {
    private static final Pattern SPACE = Pattern.compile(" ");
  
    public static void main(String[] args) throws Exception {
      if (args.length < 2) {
        System.err.println("Usage: JavaWordCount <master> <file>");
        System.exit(1);
      }
  
      JavaSparkContext ctx = new JavaSparkContext(args[0], "JavaWordCount",
          System.getenv("SPARK_HOME"), JavaSparkContext.jarOfClass(JavaWordCount.class));
      JavaRDD<String> lines = ctx.textFile(args[1], 1);
  
      JavaRDD<String> words = lines.flatMap(new FlatMapFunction<String, String>() {
        @Override
        public Iterable<String> call(String s) {
          return Arrays.asList(SPACE.split(s));
        }
      });
      
      JavaPairRDD<String, Integer> ones = words.mapToPair(new PairFunction<String, String, Integer>() {
        @Override
        public Tuple2<String, Integer> call(String s) {
          return new Tuple2<String, Integer>(s, 1);
        }
      });
      
      JavaPairRDD<String, Integer> counts = ones.reduceByKey(new Function2<Integer, Integer, Integer>() {
        @Override
        public Integer call(Integer i1, Integer i2) {
          return i1 + i2;
        }
      });
  
      List<Tuple2<String, Integer>> output = counts.collect();
      for (Tuple2<?,?> tuple : output) {
        System.out.println(tuple._1() + ": " + tuple._2());
      }
      System.exit(0);
    }
  }
  