de.ipcon.db.core

Interface TransactionMessageBusI

All Known Implementing Classes:

TransactionMessageBus

public interface TransactionMessageBusI

Handler for registering TransactionListenerI's to receive notifications on recording changes in the transaction. Allows to generate messages for virtual events as well, e.g. due to a change in a virtual attribute or non persistent entity.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	$0

Method Summary

Modifier and Type	Method and Description
void	consumeAfterSetMessage(SetValueEventI changeEvent)
boolean	createAfterAddMessage(BO bo, AttributeI attribute, BO addedBO)
boolean	createAfterRemoveMessage(BO bo, AttributeI attribute, BO removed)
boolean	createAfterSetMessage(BO bo, AttributeI attribute, java.lang.Object newValue)
boolean	createAfterSetMessage(BO bo, AttributeI attribute, java.lang.Object newValue, java.lang.Object oldValue) Creates and queues a new change message for setting a scalar or n-1 relation to a new value.
boolean	isEventFiringPaused()
void	newProcSync() Waits until the backlog is cleared and all listeners have been informed.
void	pauseFiringNewProcs() Pauses notifications for all consumers until a matching number of resumeFiringNewProcs calls have been made.
void	registerListener(TransactionListenerI l) Registers a nonnull listener to receive notification on new changes from now on.
void	resumeFiringNewProcs() Reduces the number of pause requests created by by one and resumes firing of new procs if no pause requests remain.
void	unregisterListener(TransactionListenerI l) Unregisters a nonnull listener, causing that listener to no longer receive notifications.

Field Detail

$0

static final java.lang.String $0

See Also:

Constant Field Values

Method Detail

isEventFiringPaused

boolean isEventFiringPaused()

Returns:

true if notification of listeners has been explicitly paused. When paused but #isAcceptingMessages(), then the messages will be queued and delayed until the messaging has been resumed. false, if not paused. If not paused and this bus accepts messages, then listeners will get notified. When not accepting messages, then this property has effectively no effect.

pauseFiringNewProcs

void pauseFiringNewProcs()

Pauses notifications for all consumers until a matching number of resumeFiringNewProcs calls have been made. Multiple calls to this method needs an equal number of resumes to reenable firing procs.

resumeFiringNewProcs

void resumeFiringNewProcs()

Reduces the number of pause requests created by by one and resumes firing of new procs if no pause requests remain. Will directly trigger a notification if firing is successfully resumed and a listener is available.

newProcSync

void newProcSync()

Waits until the backlog is cleared and all listeners have been informed. Will throw an IllegalStateException if firing new procs is paused. fixme: I'm not sure throwing is good idea, though. PS?

registerListener

void registerListener(TransactionListenerI l)

Registers a nonnull listener to receive notification on new changes from now on.

unregisterListener

void unregisterListener(TransactionListenerI l)

Unregisters a nonnull listener, causing that listener to no longer receive notifications.

consumeAfterSetMessage

void consumeAfterSetMessage(SetValueEventI changeEvent)

createAfterSetMessage

boolean createAfterSetMessage(BO bo,
                              AttributeI attribute,
                              java.lang.Object newValue,
                              java.lang.Object oldValue)

Creates and queues a new change message for setting a scalar or n-1 relation to a new value. If a newValue is provided, then attribute is mandatory as well. Otherwise both are currently optional.

Parameters:

bo - the bo which was changed virtually, nonnull.

attribute - the nullable attribute that was changed. While this method doesn't check if attribute is really virtual, it should be. Persistent attributes generate procs automatically by the transaction, if not, it is probably missing an include.

newValue - a nullable newValue to put into the notification, can be null if newValue isn't available directly and the up-to-date value has to be accessed by the view anyway.

oldValue - a nullable and optional oldValue to be put into the event. Should only be provided if the oldValue is readily available, because it is most likely ignored.

Returns:

true if the message has been queued, false if queuing failed for some reason (which shouldn't)

createAfterSetMessage

boolean createAfterSetMessage(BO bo,
                              AttributeI attribute,
                              java.lang.Object newValue)

createAfterAddMessage

boolean createAfterAddMessage(BO bo,
                              AttributeI attribute,
                              BO addedBO)

createAfterRemoveMessage

boolean createAfterRemoveMessage(BO bo,
                                 AttributeI attribute,
                                 BO removed)