org.eclipse.emf.transaction
Class TriggerListener

java.lang.Object
  org.eclipse.emf.transaction.ResourceSetListenerImpl
      org.eclipse.emf.transaction.TriggerListener

All Implemented Interfaces:

EventListener, ResourceSetListener, ResourceSetListener.Internal

public abstract class TriggerListener
extends ResourceSetListenerImpl

A convenient superclass for listeners that implement "triggers" to process Notifications one at a time, generating a command for each that will make dependent updates to the model.

Nested Class Summary

Nested classes/interfaces inherited from interface org.eclipse.emf.transaction.ResourceSetListener

ResourceSetListener.Internal

Constructor Summary

TriggerListener()
Initializes me with the default filter.

TriggerListener(NotificationFilter filter)
Initializes me with the specified filter.

Method Summary

boolean	isPrecommitOnly() I want only ppre-commit events, not post-commit events.
Command	transactionAboutToCommit(ResourceSetChangeEvent event) Implements the trigger callback by processing the event's notifications one by one, delegating to the trigger(org.eclipse.emf.transaction.TransactionalEditingDomain, org.eclipse.emf.common.notify.Notification) method for each to generate a command.
protected abstract Command	trigger(TransactionalEditingDomain domain, Notification notification) Implemented by subclasses to provide a trigger command for a single change in the model.

Methods inherited from class org.eclipse.emf.transaction.ResourceSetListenerImpl

getFilter, getTarget, isAggregatePrecommitListener, isPostcommitOnly, resourceSetChanged, setTarget, unsetTarget

Methods inherited from class java.lang.Object

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

Constructor Detail

TriggerListener

public TriggerListener()

Initializes me with the default filter.

TriggerListener

public TriggerListener(NotificationFilter filter)

Initializes me with the specified filter.

Parameters:

filter - a notification filter, or null for the default

Method Detail

transactionAboutToCommit

public Command transactionAboutToCommit(ResourceSetChangeEvent event)
                                 throws RollbackException

Implements the trigger callback by processing the event's notifications one by one, delegating to the trigger(org.eclipse.emf.transaction.TransactionalEditingDomain, org.eclipse.emf.common.notify.Notification) method for each to generate a command. The commands created by the subclass are chained in the order that they are received from the subclass.

Specified by:

transactionAboutToCommit in interface ResourceSetListener

Overrides:

transactionAboutToCommit in class ResourceSetListenerImpl

Parameters:

event - the event object describing the changes that occurred in the resource set

Returns:

a composite of the commands returned by the subclass implementation of the trigger(org.eclipse.emf.transaction.TransactionalEditingDomain, org.eclipse.emf.common.notify.Notification) method

Throws:

RollbackException - to force a roll-back of the current transaction

trigger

protected abstract Command trigger(TransactionalEditingDomain domain,
                                   Notification notification)

Implemented by subclasses to provide a trigger command for a single change in the model.

Parameters:

domain - the editing domain

notification - the notification describing a change in the model

Returns:

the command, or null if none is required for this particular notification

isPrecommitOnly

public boolean isPrecommitOnly()

I want only ppre-commit events, not post-commit events.

Specified by:

isPrecommitOnly in interface ResourceSetListener

Overrides:

isPrecommitOnly in class ResourceSetListenerImpl

Returns:

true if I only am interested in pre-commit events; false, otherwise