/** Bean init method to perform one time setup of the Hazelcast cluster node. */
public void init() {
// validate bean setup
if (this.hazelcastInstance == null) {
throw new IllegalArgumentException(
"The 'hazelcastInstance' property (HazelcastInstance) is mandatory.");
}
if (this.hazelcastTopicName == null || this.hazelcastTopicName.length() == 0) {
throw new IllegalArgumentException(
"The 'hazelcastTopicName' property (String) is mandatory.");
}
// cluster topic initialisation
ITopic<String> topic = this.hazelcastInstance.getTopic(this.hazelcastTopicName);
if (topic == null) {
throw new IllegalArgumentException(
"Did not find Hazelcast topic with name: '"
+ this.hazelcastTopicName
+ "' - cannot init.");
}
// find the beans that are interested in cluster messages and register them with the service
Map<String, ClusterMessageAware> beans =
this.applicationContext.getBeansOfType(ClusterMessageAware.class);
this.clusterBeans = new HashMap<>();
for (final String id : beans.keySet()) {
final ClusterMessageAware bean = beans.get(id);
final String messageType = bean.getClusterMessageType();
// beans that do not specify a message type can still post messages via the service or just
// keep a reference
// but they are not registered in the list of handler beans that can accept cluster messages
if (messageType != null) {
if (this.clusterBeans.containsKey(messageType)) {
throw new IllegalStateException(
"ClusterMessageAware bean with id '"
+ id
+ "' attempted to register with existing Message Type: "
+ messageType);
}
this.clusterBeans.put(messageType, bean);
}
bean.setClusterService(this);
}
if (logger.isDebugEnabled()) {
logger.debug("Registered beans for cluster messages:");
for (final String id : beans.keySet()) {
logger.debug(id + " [" + beans.get(id).getClusterMessageType() + "]");
}
}
// start listening for cluster messages
this.clusterTopic = topic;
this.clusterTopic.addMessageListener(this);
logger.info("Init complete for Hazelcast cluster - listening on topic: " + hazelcastTopicName);
}
/**
* Hazelcast MessageListener implementation - called when a message is received from a cluster
* node
*
* @param message Cluster message JSON string
*/
@Override
public void onMessage(final Message<String> message) {
final boolean debug = logger.isDebugEnabled();
// process message objects and extract the payload
final String msg = message.getMessageObject();
final MessageProcessor proc = new MessageProcessor(msg);
if (!proc.isSender()) {
if (debug) logger.debug("Received message of type:" + proc.getMessageType() + "\r\n" + msg);
// call an implementation of a message handler bean
final ClusterMessageAware bean = this.clusterBeans.get(proc.getMessageType());
if (bean != null) {
bean.onClusterMessage(proc.getMessagePayload());
} else {
logger.warn(
"Received message of unknown type - no handler bean found: " + proc.getMessageType());
}
}
}