com.hp.util.dcord

Class Namespace

java.lang.Object

com.hp.util.type.AbstractValueType<String>

com.hp.util.dcord.Namespace

All Implemented Interfaces:

Serializable

public final class Namespace
extends AbstractValueType<String>

Coordination (or distributed) service namespace.

A namespace is used to identify instances of coordination services. All nodes using the a coordination service must use the same namespace.

For example, if distributed queues are used, the namespace will identify a specific instance of a queue so a process puts and takes elements from the right queue.

Author:

Fabiel Zuniga

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
static Namespace	forReplicatedProcess(Class<?> replicatedProcess) Creates a namespace to be used when all the nodes run the same code and use a single instance of a distributed service (Like queues).
static Namespace	valueOf(String serviceId) Creates a custom namespace.
static Namespace	valueOf(String serviceId, String componentId) Creates a custom namespace.

Methods inherited from class com.hp.util.type.AbstractValueType

equals, getValue, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

valueOf

public static Namespace valueOf(String serviceId)
                         throws NullPointerException,
                                IllegalArgumentException

Creates a custom namespace.

Use this factory method if:

• If processes running different code (Different classes for example) will coordinate using the same distributed service. Assign a common namespace across involved processes.
• If multiple instances of the same distributed service will be used by the same process (For example a process using multiple distributed queues). Assign a different namespace to each service instance.

Parameters:

serviceId - id of the distributed service, for example id (or name) of a queue, map, lock, etc.

Returns:

a namespace

Throws:

NullPointerException - if serviceId is null

IllegalArgumentException - if serviceId is empty

valueOf

public static Namespace valueOf(String serviceId,
                                String componentId)
                         throws NullPointerException,
                                IllegalArgumentException

Creates a custom namespace.

This method is similar to valueOf(String) and thus it should be used in the same cases. However this method makes explicit that multiple components (or applications) are used and thus another level of namespace is needed to avoid conflicts when two components (or applications) define the same id (or name) for a distributed service (Like queues).

Parameters:

serviceId - id of the distributed service, for example id (or name) of a queue, map, lock, etc.

componentId - id of the component or application

Returns:

a namespace

Throws:

NullPointerException - if either serviceId or componentId is null

IllegalArgumentException - if either serviceId or componentId is empty

forReplicatedProcess

public static Namespace forReplicatedProcess(Class<?> replicatedProcess)
                                      throws NullPointerException

Creates a namespace to be used when all the nodes run the same code and use a single instance of a distributed service (Like queues). The same class running on different nodes will coordinate to its peers using a single instance of a distributed service.

This factory method is convenient because the namespace is guaranteed to be unique among different processes types.

Parameters:

replicatedProcess - process replicated in all nodes that will make use of a coordination service

Returns:

a namespace

Throws:

NullPointerException - if replicatedProcess is null