Eclipse EMF Model Transaction Development Guide (Galileo) - TriggerListener (EMF Model Transaction Javadoc)

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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
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