Hazelcast Client for Quarkus

Hazelcast IMDG is a distributed in-memory object store and compute engine that supports a wide variety of data structures such as Map, Set, List, MultiMap, RingBuffer, HyperLogLog.

Use Hazelcast IMDG to store your data in RAM, spread and replicate it across a cluster of machines, and perform data-local computation on it.

Hazelcast is:

• cloud and Kubernetes friendly
• often used as a Distributed Cache amongst other use cases

See the official guide here.

Features

• The HazelcastInstance bean is initialized lazily by Quarkus, if you want eager initialization, make sure to double-check Quarkus Documentation.

Configuration

After configuring quarkus-universe BOM:

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>io.quarkus</groupId>
            <artifactId>quarkus-universe-bom</artifactId>
            <version>${insert.newest.quarkus.version.here}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

You can just configure the hazelcast-client extension by adding the following dependency:

<dependency>
    <groupId>com.hazelcast</groupId>
    <artifactId>quarkus-hazelcast-client</artifactId>
</dependency>

NOTE: You can bootstrap a new application quickly by using code.quarkus.io and choosing quarkus-hazelcast-client

Quarkus hazelcast-client configuration

The extension exposes a single native-mode-compatible Hazelcast Client bean (HazelcastInstance) which can be directly injected into your beans:

private final HazelcastInstance hazelcastInstance;

public UsersService(HazelcastInstance hazelcastInstance) {
    this.hazelcastInstance = hazelcastInstance;
}

By default, client will try to connect to a Hazelcast instance running on the host using port 5701.

Defaults can be customized using application.properties entries such as:

quarkus.hazelcast-client.cluster-members
quarkus.hazelcast-client.outbound-port-definitions
quarkus.hazelcast-client.outbound-ports
quarkus.hazelcast-client.cluster-name
quarkus.hazelcast-client.labels
quarkus.hazelcast-client.connection-timeout

For example:

quarkus.hazelcast-client.cluster-members=localhost:5701

If you don't provide a port number, Hazelcast Client will try to autodetect it:

quarkus.hazelcast-client.cluster-members=localhost

You can also pass a comma-separate list of values as a single entry:

quarkus.hazelcast-client.cluster-members=localhost:5701,localhost:5702

If you need more, use a standard hazelcast-client.yml/hazelcast-client.xml-based configuration (described below) or wire-up your own HazelcastInstance bean.

Keep in mind that you will still be able to benefit from GraalVM compatibility!

Configuration Files

Configuration using hazelcast-client.yml or hazelcast-client.xml

In order to configure the client using the hazelcast-client.yml/hazelcast-client.xml file, place the configuration file in the src/main/resources directory.

Keep in mind that configuration entries from hazelcast-client.yml/xml are overridden by quarkus.hazelcast-client.* entries so it's a good idea to stick to one of these exclusively.

Testing

To make testing simple, the extension provides the HazelcastServerTestResource which automatically launches an embedded Hazelcast instance with defaults settings and manages its lifecycle:

 @QuarkusTest
 @QuarkusTestResource(HazelcastServerTestResource.class)
 public class HazelcastAwareTest {

     @Test
     public void test() {
         // you can safely call embedded Hazelcast instance from here
     }
 }

Maven dependency:

<dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-test-hazelcast</artifactId>
    <scope>test</scope>
</dependency>

Compatibility Matrix

• 1.0.x is compatible with Quarkus 1.6.x-1.7.x (no longer maintained)
• 1.1.1 is compatible with Quarkus 1.8.x+ and Hazelcast 4.0.x and 4.1.x and JDK 8+
• 1.2.0 is compatible with Quarkus 1.13.x+ and Hazelcast 4.x and JDK 8+
• 3.0.0 is compatible with Quarkus 2.x+ and Hazelcast 4.x and JDK 8+
• 4.0.0 is compatible with Quarkus 3.x+ and Hazelcast 4.x and JDK 11+

Limitations (native mode)

There's no support for:

• Default Java serialization
• User code deployment
• Hazelcast SPI support on OSGi
• JCache integration
• JMX