gnu.cajo

Class Cajo.Registrar

java.lang.Object

gnu.cajo.Cajo.Registrar

Enclosing class:

Cajo

public static final class Cajo.Registrar
extends Object

This internal use only helper class maintains a registry of exported objects. It cannot be instantiated outside this class, it is made public only because it is being invoked reflectively. It uses UDP multicasts to find other instances of registries, and shares references between them.

Method Summary

Methods

Modifier and Type	Method and Description
Object	multicast(Multicast multicast) This method is called either when a Cajo instance starts up, or exports an object reference.
void	register(Vector elements) This method is called either by remote JVMs to provide a copy of their registry, in response to a startup or export announcement.
Vector	request() This method allows remote JVMs to request the contents of the registry.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

multicast

public Object multicast(Multicast multicast)
                 throws Exception

This method is called either when a Cajo instance starts up, or exports an object reference. All operating servers will request the collection of references owned by the remote JVM, and correspondingly send a copy of their registries.

Parameters:

multicast - A reference to the announcing JVM

Returns:

null To keep the multicast object listening

Throws:

Exception - if the request for remote references failed, or the sending its reference collection failed, for either network, or application specific reasons.

register

public void register(Vector elements)

This method is called either by remote JVMs to provide a copy of their registry, in response to a startup or export announcement. The registries will be merged, and duplicate references discarded.

Parameters:

elements - A collection of remote object references

request

public Vector request()

This method allows remote JVMs to request the contents of the registry. The contents of the registry are dynamic, changing with the exports, and shutdowns, of remote servers.

Returns:

The collection of remote object references currently registered