Hazelcast Jet is a distributed stream processing engine that allows you to process and analyze data in real-time. It provides a simple and intuitive API for working with data streams. In this article, we will explore how to work with Hazelcast Jet data streams in Java.

Setting up Hazelcast Jet

Before working with Hazelcast Jet data streams, you need to set up Hazelcast Jet in your Java project. You can do this by adding the necessary dependencies to your project’s build file. For example, if you are using Maven, you can add the following dependencies:

<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast-jet-core</artifactId>
    <version>4.4.1</version>
</dependency>
<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>hazelcast-jet-server</artifactId>
    <version>4.4.1</version>
</dependency>

Once you have set up the dependencies, you can start working with Hazelcast Jet data streams.

Creating a Data Stream

To create a data stream in Hazelcast Jet, you can use the StreamSource class. This class provides various methods to create data streams from different sources, such as files, databases, and Hazelcast IMDG collections.

Here is an example of creating a data stream from a file:

StreamSource<String> fileSource = StreamSource.files("path/to/file.txt");

Applying Transformations to a Data Stream

Once you have a data stream, you can apply various transformations to process the data. Hazelcast Jet provides a rich set of transformation operators, such as map, filter, and flatMap, which allow you to modify and filter the data.

Here is an example of applying a map transformation to convert a stream of strings to uppercase:

DataStream<String> uppercaseStream = fileSource.map(String::toUpperCase);

Consuming a Data Stream

To consume the data from a data stream, you can use the SinkBuilder class. This class provides methods to create sinks for different output destinations, such as files, databases, and Hazelcast IMDG maps.

Here is an example of consuming a data stream by writing the data to a file:

SinkBuilder.sinkToFile("path/to/output.txt").build().sink(uppercaseStream);

Running the Data Stream Job

To run the data stream job, you need to create a Hazelcast Jet instance and submit the job to it. The Hazelcast Jet instance coordinates the execution of the job across the cluster.

Here is an example of running a data stream job:

JetInstance jet = Jet.newJetInstance();
jet.newJob(uppercaseStream).execute();

Conclusion

Hazelcast Jet provides a powerful and flexible framework for working with data streams in Java. In this article, we have seen how to create a data stream, apply transformations, consume the data, and run the data stream job. With Hazelcast Jet, you can easily build high-performance and scalable data processing applications.

#Java #HazelcastJet #DataStreams