com.kabira.store

Class Extent<T>

java.lang.Object

com.kabira.store.Extent<T>

Type Parameters:

T - Managed type parameter

@Managed
public abstract class Extent<T>
extends java.lang.Object

Class for receiving notifications of ManagedObject.extent(java.lang.Class<T>) calls.

An Extent notifier does not directly return results. The notification provides an opportunity to change the contents of a Managed object extent (creating or deleting Managed objects) before the extent iteration is done. For example, it could be used for creating Managed objects from data in a database.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Extent(java.lang.Class<T> klass) Constructor.

Method Summary

Modifier and Type	Method and Description
abstract void	extent(java.lang.Class<? extends T> klass, LockMode lockMode) Notifier method for ManagedObject.extent(Class) calls.
static Extent<?>	getNotifier(java.lang.Class<?> klass) Return the currently installed notifier for a Managed class.

Methods inherited from class java.lang.Object

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

Constructor Detail

Extent

protected Extent(java.lang.Class<T> klass)
          throws ManagedClassError

Constructor.

Creating an instance automatically installs it as the extent notifier for Managed class T.

If a notifier is already installed for the class, the new instance replaces the previous instance.

Deleting a notifier automatically uninstalls it.

Notifiers are automatically deleted when the JVM shuts down. Notifiers created in other JVMs are not affected.

A separate notifier may be set for each class in a hierarchy.

If no notifier is installed for a class, it inherits the notifier of its parent.

When a ManagedObject.extent(java.lang.Class<T>) result set is iterated, the installed notifier for its type and subtypes are called before executing the extent call. The notifiers are called starting at the most extended subtype up through the type hierarchy ending on the class passed to the extent call. The order of notifier invocation for multiple types at the same level of the type hierarchy is undefined.

Parameters:

klass - The Managed class base to receive ManagedObject.extent() notifications for.

Throws:

ManagedClassError - klass is not managed.

Method Detail

getNotifier

public static Extent<?> getNotifier(java.lang.Class<?> klass)

Return the currently installed notifier for a Managed class. Inheritance is not considered.

If there is no notifier for the Managed class null is returned.

Parameters:

klass - The class to search.

Returns:

Extent or null.

Throws:

ManagedClassError - If klass is not managed.

extent

public abstract void extent(java.lang.Class<? extends T> klass,
                            LockMode lockMode)

Notifier method for ManagedObject.extent(Class) calls. May be used to create (or delete) objects in the extent before the extent is iterated.

Called by the system when a ManagedObject.extent(java.lang.Class<T>) result set is iterated, before executing the extent call.

Called on each of the nodes in the QueryScope of the extent call.

Called before the ManagedObject.extent() is performed.

Work done within Extent.extent() will not generate calls to com.kabira.store notifiers on the local node.

Note: work done within Extent.extent() will generate calls to com.kabira.store notifiers on remote nodes.

Parameters:

klass - The Managed class for the extent() call. This may be a subtype of the notifier's managed class type.

lockMode - The lock mode for the extent call. The notifier implementation should attempt to honor this lock mode, but there is no enforcement.