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Using Variables

In your Hazelcast and/or Hazelcast Client declarative configuration, you can use variables to set the values of the elements. This is valid when you set a system property programmatically or you use the command line interface. You can use a variable in the declarative configuration to access the values of the system properties you set.

For example, see the following command that sets two system properties.

-Dcluster.name=dev

Let’s get the values of these system properties in the declarative configuration of Hazelcast, as shown below.

In the XML configuration:

<hazelcast>
    <group>
        <name>${group.name}</name>
    </group>
</hazelcast>

In the YAML configuration:

hazelcast:
  group:
    name: ${group.name}

This also applies to the declarative configuration of Hazelcast Java Client, as shown below.

<hazelcast-client>
    <group>
        <name>${group.name}</name>
    </group>
</hazelcast-client>
hazelcast-client:
  group:
    name: ${group.name}

If you do not want to rely on the system properties, you can use the XmlConfigBuilder or YamlConfigBuilder and explicitly set a Properties instance, as shown below.

Properties properties = new Properties();

// fill the properties, e.g., from database/LDAP, etc.

XmlConfigBuilder builder = new XmlConfigBuilder();
builder.setProperties(properties);
Config config = builder.build();
HazelcastInstance hz = Hazelcast.newHazelcastInstance(config);