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>
