Table of Contents
Hazelcast can be configured through xml or using configuration api or even mix of both.
Xml Configuration
If you are using default Hazelcast instance
(Hazelcast.getDefaultInstance()) or creating new Hazelcast
instance with passing
null
parameter
(Hazelcast.newHazelcastInstance(null)), Hazelcast will look
into two places for the configuration file:
System property:
Hazelcast will first
check if "hazelcast.config" system property is set to
a file path. Example:
-Dhazelcast.config=C:/myhazelcast.xml.
Classpath:
If config file is not set
as a system property, Hazelcast will check classpath for
hazelcast.xml
file.
If Hazelcast doesn't find any config file, it will happily start with
default configuration (hazelcast-default.xml) located in
hazelcast.jar. (Before configuring Hazelcast, please try to
work with default configuration to see if it works for you. Default should be just
fine for most of the users. If not, then consider custom configuration for your
environment.)
If you want to specify your own configuration file to create
Config, Hazelcast supports several ways including filesystem,
classpath, InputStream, URL etc.:
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);
Programmatic Configuration
To configure Hazelcast programatically, just instantiate a
Config object and set/change its properties/attributes due to
your needs.
Config cfg = new Config(); cfg.setPort(5900); cfg.setPortAutoIncrement(false); NetworkConfig network = cfg.getNetworkConfig(); Join join = network.getJoin(); join.getMulticastConfig().setEnabled(false); join.getTcpIpConfig().addMember("10.45.67.32").addMember("10.45.67.100") .setRequiredMember("192.168.10.100").setEnabled(true); network.getInterfaces().setEnabled(true).addInterface("10.45.67.*"); MapConfig mapCfg = new MapConfig(); mapCfg.setName("testMap"); mapCfg.setBackupCount(2); mapCfg.getMaxSizeConfig().setSize(10000); mapCfg.setTimeToLiveSeconds(300); MapStoreConfig mapStoreCfg = new MapStoreConfig(); mapStoreCfg.setClassName("com.hazelcast.examples.DummyStore").setEnabled(true); mapCfg.setMapStoreConfig(mapStoreCfg); NearCacheConfig nearCacheConfig = new NearCacheConfig(); nearCacheConfig.setMaxSize(1000).setMaxIdleSeconds(120).setTimeToLiveSeconds(300); mapCfg.setNearCacheConfig(nearCacheConfig); cfg.addMapConfig(mapCfg);
After creating
Config
object, you can use it to initialize
default Hazelcast instance or create a new Hazelcast instance.
Hazelcast.init(cfg);
Hazelcast.newHazelcastInstance(cfg);
HazelcastInstance with a name:
To create a named
HazelcastInstance
you should set
instanceName
of
Config
object.
Config cfg = new Config();
config.setInstanceName('my-instance');
Hazelcast.newHazelcastInstance(config);
To retrieve an existing
HazelcastInstance
using its name, use;
Hazelcast.getHazelcastInstanceByName('my-instance');
To retrieve all existingHazelcastInstances, use;
Hazelcast.getAllHazelcastInstances();
By specifying group-name and group-password, you can separate your clusters in a simple way; dev group, production group, test group, app-a group etc...
<hazelcast>
<group>
<name>dev</name>
<password>dev-pass</password>
</group>
...
</hazelcast>
You can also set the groupName with
Config
API.
JVM can host multiple Hazelcast instances (nodes).
Each node can only participate in one group and it only joins to
its own group, does not mess with others. Following code creates 3 separate
Hazelcast nodes,
h1
belongs to
app1
cluster, while
h2
and
h3
are belong to
app2
cluster.
Config configApp1 = new Config();
configApp1.getGroupConfig().setName("app1");
Config configApp2 = new Config();
configApp2.getGroupConfig().setName("app2");
HazelcastInstance h1 = Hazelcast.newHazelcastInstance(configApp1);
HazelcastInstance h2 = Hazelcast.newHazelcastInstance(configApp2);
HazelcastInstance h3 = Hazelcast.newHazelcastInstance(configApp2);