org.apache.spark.examples.JavaWordCount Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of spark-examples_2.9.3 Show documentation
The newest version!
/*
 * 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;

public class JavaWordCount {
  public static void main(String[] args) throws Exception {
    if (args.length < 2) {
      System.err.println("Usage: JavaWordCount  ");
      System.exit(1);
    }

    JavaSparkContext ctx = new JavaSparkContext(args[0], "JavaWordCount",
        System.getenv("SPARK_HOME"), System.getenv("SPARK_EXAMPLES_JAR"));
    JavaRDD lines = ctx.textFile(args[1], 1);

    JavaRDD words = lines.flatMap(new FlatMapFunction() {
      public Iterable call(String s) {
        return Arrays.asList(s.split(" "));
      }
    });
    
    JavaPairRDD ones = words.map(new PairFunction() {
      public Tuple2 call(String s) {
        return new Tuple2(s, 1);
      }
    });
    
    JavaPairRDD counts = ones.reduceByKey(new Function2() {
      public Integer call(Integer i1, Integer i2) {
        return i1 + i2;
      }
    });

    List> output = counts.collect();
    for (Tuple2 tuple : output) {
      System.out.println(tuple._1 + ": " + tuple._2);
    }
    System.exit(0);
  }
}