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>