In this blog post, we will explore how to leverage Hazelcast Jet to execute batch jobs in Java applications. Hazelcast Jet is an open-source distributed processing engine that provides fast and reliable batch processing capabilities.

What is Hazelcast Jet?

Hazelcast Jet is a distributed data processing engine built on top of the Hazelcast IMDG (In-Memory Data Grid) platform. It allows you to process large volumes of data efficiently and scale horizontally as your data processing needs grow.

Why Use Batch Jobs?

Batch processing is a common requirement in many applications, such as data ingestion, data filtering, data transformation, and data analytics. With Hazelcast Jet, you can easily parallelize and distribute batch jobs, enabling faster and more efficient processing of large datasets.

Setting up Hazelcast Jet

To get started, you need to include the Hazelcast Jet dependency in your Java project. Add the following Maven dependency to your pom.xml:

<dependency>
    <groupId>com.hazelcast.jet</groupId>
    <artifactId>hazelcast-jet</artifactId>
    <version>4.3.1</version>
</dependency>

Creating a Batch Job

Let’s assume you have a list of users with their details stored in a CSV file. You want to read this file, apply some processing logic, and store the result in a database.

First, create a class that implements the Processor interface provided by Hazelcast Jet. This class will define the processing logic for your batch job:

public class UserProcessor implements Processor {

    @Override
    public void process(Item item) {
        // Process each item (user) here
    }
}

Next, create a main class to set up Hazelcast Jet and execute the batch job:

public class BatchJobRunner {

    public static void main(String[] args) {
        Pipeline pipeline = Pipeline.create();
        
        // Read CSV file
        pipeline.readFrom(Sources.files("users.csv"))
        
        // Apply processing logic
        .apply(new UserProcessor())
        
        // Write to database
        .writeTo(Sinks.jdbc(
                () -> DriverManager.getConnection("jdbc:mysql://localhost:3306/mydb?user=root&password=secret"),
                User::toPreparedStatement,
                new JdbcUpdateOptions()))
                
        // Execute the job
        JobConfig jobConfig = new JobConfig();
        JetInstance jet = Jet.newJetInstance();
        Job job = jet.newJob(pipeline, jobConfig);
        job.join();
    }
}

In this example, we use the Sources.files() method to read the CSV file, apply the processing logic using the UserProcessor class, and write the result to a MySQL database using the Sinks.jdbc() method. Finally, we create a JetInstance, configure the job, and execute it.

Conclusion

Hazelcast Jet provides a simple and efficient way to execute batch jobs in Java applications. By leveraging its distributed data processing capabilities, you can process large datasets faster and more reliably. Whether it’s data ingestion, filtering, transformation, or analytics, Hazelcast Jet is a powerful tool for your batch processing needs.

#hazelcast #jet #batchprocessing