Count the Wor(l)d with Apache Beam

Count the wor(l)d with Apache Beam

About Beam : http://blog.nanthrax.net/2016/01/introducing-apache-dataflow/

On a  brief note:

Apache Beam is an open source, a unified programming model that you can use to create a data processing Pipeline. A Pipeline is a chain of processes on the data. Jobs are described in Pipeline. User has to write only this Pipeline part.

The Apache Beam SDK is composed by four parts:

• Pipelines are the streaming and processing logic that you want to implement. It’s a chain of processes. Basically, in a pipeline, you read data from a source, you apply transformations on the data, and eventually send the data to a destination (named sink in Dataflow wording).
• PCollection is the object transported inside a pipeline. It’s the container of the data, flowing between each step of the pipeline.
• Transform is a step of a pipeline. It takes an incoming PCollection and creates an outcoming PCollection. You can implement your own transform function.
• Sink and Source are used to retrieve data as input (first step) of a pipeline, and eventually send the data outside of the pipeline.

Here is a Word Count sample ( it works with Jdk1.8 only)

package com.test;


import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.io.TextIO;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.Count;
import org.apache.beam.sdk.transforms.Filter;
import org.apache.beam.sdk.transforms.FlatMapElements;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.values.KV;
import org.apache.beam.sdk.values.TypeDescriptor;

import java.util.Arrays;

/**
 * Created by Siva on 6/16/16.
 */
public class WordCount {
    public static void main(String[] args) {
        // Step1: Create a Pipeline
        PipelineOptions options = PipelineOptionsFactory.create();
        // Step2: set filter options
        Pipeline p = Pipeline.create(options);
        // Step2 & 3: Apply Filters.
        p.apply(TextIO.Read.from("/Users/Siva/beam-files/count.txt"))
                .apply(FlatMapElements.via((String word) -> Arrays.asList(word.split("[^a-zA-Z']+")))
                        .withOutputType(new TypeDescriptor() {
                        }))
                .apply(Filter.byPredicate((String word) -> !word.isEmpty()))
                .apply(Count.perElement())
                .apply(MapElements
                        .via((KV wordCount) -> wordCount.getKey() + ": " + wordCount.getValue())
                        .withOutputType(new TypeDescriptor() {
                        }))
         // Step4: Write output
                .apply(TextIO.Write.to("/Users/Siva/beam-files/count-output.txt"));

        p.run();

        System.out.println(">>> Done");

    }

}

And the pom.xml should look like below.

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>groupId</groupId>
    <artifactId>Temp</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.apache.beam</groupId>
            <artifactId>beam-sdks-java-core</artifactId>
            <version>0.1.0-incubating</version>
        </dependency>
        <dependency>
            <groupId>org.apache.beam</groupId>
            <artifactId>beam-runners-direct-java</artifactId>
            <version>0.1.0-incubating</version>
            <scope>runtime</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>