org.apache.spark.streaming.examples.JavaNetworkWordCount.java Source code

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Here is the source code for org.apache.spark.streaming.examples.JavaNetworkWordCount.java

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/*
 * 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.streaming.examples;

import com.google.common.collect.Lists;
import scala.Tuple2;
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 org.apache.spark.streaming.Duration;
import org.apache.spark.streaming.api.java.JavaDStream;
import org.apache.spark.streaming.api.java.JavaPairDStream;
import org.apache.spark.streaming.api.java.JavaStreamingContext;

import java.util.regex.Pattern;

/**
 * Counts words in UTF8 encoded, '\n' delimited text received from the network every second.
 * Usage: NetworkWordCount <master> <hostname> <port>
 *   <master> is the Spark master URL. In local mode, <master> should be 'local[n]' with n > 1.
 *   <hostname> and <port> describe the TCP server that Spark Streaming would connect to receive data.
 *
 * To run this on your local machine, you need to first run a Netcat server
 *    `$ nc -lk 9999`
 * and then run the example
 *    `$ ./run org.apache.spark.streaming.examples.JavaNetworkWordCount local[2] localhost 9999`
 */
public final class JavaNetworkWordCount {
    private static final Pattern SPACE = Pattern.compile(" ");

    private JavaNetworkWordCount() {
    }

    public static void main(String[] args) {
        if (args.length < 3) {
            System.err.println("Usage: JavaNetworkWordCount <master> <hostname> <port>\n"
                    + "In local mode, <master> should be 'local[n]' with n > 1");
            System.exit(1);
        }

        StreamingExamples.setStreamingLogLevels();

        // Create the context with a 1 second batch size
        JavaStreamingContext ssc = new JavaStreamingContext(args[0], "JavaNetworkWordCount", new Duration(1000),
                System.getenv("SPARK_HOME"), JavaStreamingContext.jarOfClass(JavaNetworkWordCount.class));

        // Create a NetworkInputDStream on target ip:port and count the
        // words in input stream of \n delimited text (eg. generated by 'nc')
        JavaDStream<String> lines = ssc.socketTextStream(args[1], Integer.parseInt(args[2]));
        JavaDStream<String> words = lines.flatMap(new FlatMapFunction<String, String>() {
            @Override
            public Iterable<String> call(String x) {
                return Lists.newArrayList(SPACE.split(x));
            }
        });
        JavaPairDStream<String, Integer> wordCounts = words.mapToPair(new PairFunction<String, String, Integer>() {
            @Override
            public Tuple2<String, Integer> call(String s) {
                return new Tuple2<String, Integer>(s, 1);
            }
        }).reduceByKey(new Function2<Integer, Integer, Integer>() {
            @Override
            public Integer call(Integer i1, Integer i2) {
                return i1 + i2;
            }
        });

        wordCounts.print();
        ssc.start();
        ssc.awaitTermination();
    }
}