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Configuring Programmatically

Besides declarative configuration, you can configure your cluster programmatically. For this you can create a Config object, set/change its properties and attributes and use this Config object to create a new Hazelcast member. Following is an example code which configures some network and Hazelcast Map properties.

        Config config = new Config();
        config.getNetworkConfig().setPort( 5900 )
                .setPortAutoIncrement( false );

        MapConfig mapConfig = new MapConfig();
        mapConfig.setName( "testMap" )
                .setBackupCount( 2 )
                .setTimeToLiveSeconds( 300 );

To create a Hazelcast member with the above example configuration, pass the configuration object as shown below:

HazelcastInstance hazelcast = Hazelcast.newHazelcastInstance( config );
The Config must not be modified after the Hazelcast instance is started. In other words, all configuration must be completed before creating the HazelcastInstance. Certain additional configuration elements can be added at runtime as described in the Dynamically Adding Data Structure Configuration on a Cluster section.

You can also create a named Hazelcast member. In this case, you should set instanceName of Config object as shown below:

Config config = new Config();
config.setInstanceName( "my-instance" );
Hazelcast.newHazelcastInstance( config );

To retrieve an existing Hazelcast member by its name, use the following:

Hazelcast.getHazelcastInstanceByName( "my-instance" );

To retrieve all existing Hazelcast members, use the following:

Hazelcast.getAllHazelcastInstances();
Hazelcast performs schema validation through the file hazelcast-config-3.12.12.xsd which comes with your Hazelcast libraries. Hazelcast throws a meaningful exception if there is an error in the declarative or programmatic configuration.

If you want to specify your own configuration file to create Config, Hazelcast supports several ways including filesystem, classpath, InputStream and URL.

Building Config from the XML declarative configuration:

  • Config cfg = new XmlConfigBuilder(xmlFileName).build();

  • Config cfg = new XmlConfigBuilder(inputStream).build();

  • Config cfg = new ClasspathXmlConfig(xmlFileName);

  • Config cfg = new FileSystemXmlConfig(configFilename);

  • Config cfg = new UrlXmlConfig(url);

  • Config cfg = new InMemoryXmlConfig(xml);

Building Config from the YAML declarative configuration:

  • Config cfg = new YamlConfigBuilder(yamlFileName).build();

  • Config cfg = new YamlConfigBuilder(inputStream).build();

  • Config cfg = new ClasspathYamlConfig(yamlFileName);

  • Config cfg = new FileSystemYamlConfig(configFilename);

  • Config cfg = new UrlYamlConfig(url);

  • Config cfg = new InMemoryYamlConfig(yaml);