You can implement the HazelcastInstanceAware
interface to access distributed objects for cases where an object is deserialized and needs access to HazelcastInstance.
Let's implement it for the Employee
class mentioned in the Custom Serialization section.
public class Employee
implements Serializable, HazelcastInstanceAware {
private static final long serialVersionUID = 1L;
private String surname;
private transient HazelcastInstance hazelcastInstance;
public Person( String surname ) {
this.surname = surname;
}
@Override
public void setHazelcastInstance( HazelcastInstance hazelcastInstance ) {
this.hazelcastInstance = hazelcastInstance;
System.out.println( "HazelcastInstance set" );
}
@Override
public String toString() {
return String.format( "Person(surname=%s)", surname );
}
}
After deserialization, the object is checked to see if it implements HazelcastInstanceAware
and the method setHazelcastInstance
is called. Notice the hazelcastInstance
is transient
. This is because this field should not be serialized.
It may be a good practice to inject a HazelcastInstance into a domain object, e.g., Employee
in the above sample, when used together with Runnable
/Callable
implementations. These runnables/callables are executed by IExecutorService
which sends them to another machine. And after a task is deserialized, run/call method implementations need to access HazelcastInstance.
We recommend you only set the HazelcastInstance field while using setHazelcastInstance
method and you not execute operations on the HazelcastInstance. The reason is that when HazelcastInstance is injected for a HazelcastInstanceAware
implementation, it may not be up and running at the injection time.