de.ipcon.db.core

Class TransactionMessageBus

java.lang.Object

de.ipcon.db.core.TransactionMessageBus

All Implemented Interfaces:

TransactionMessageBusI

public class TransactionMessageBus
extends java.lang.Object
implements TransactionMessageBusI

This class handles the TransactionListenerI aspect of the transaction and additionally provides a way for non persistent BOs or virtual attributes to trigger virtual events as well.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	MAGIC_WHOLE_BO_ATTRIBUTE Attribute'name' used to represent a refresh of all scalars and n-1 relations on the BOProc.

Constructor Summary

Constructors

Constructor and Description
TransactionMessageBus(Transaction _tx)

Method Summary

Modifier and Type	Method and Description
void	consumeAfterSetMessage(SetValueEventI changeEvent)
static void	consumeScriptedAttributeChange(SetValueEventI changeEvent) This method will call consumeAfterSetMessage on the MessageBus for the BOs loadingTransaction.
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.
void	disableSynchronousEventsForUnittests() Disable synchronous events again.
void	doSignalProcListeners()
void	enableSynchronousEventsForUnittests() New Events will trigger a notification of listeners directly, in the thread that triggered the event, skipping the asynchronous event collection behaviour.
void	fireCheckPoint()
void	fireNewProcs() Notify the NewProcsRunner thread that this MessageBus has new messages to handle.
void	forceResumeFiringNewProcs() Ignores previous pauses to event firing by any sources and reenables it
Transaction	getTransaction()
boolean	isAcceptingMessages()
boolean	isEventFiringPaused()
static void	killNewProcsRunner() This should only be called if a classloader is disposed of and we need to stop this class's NewProcsRunner!
void	newProcSync() Waits until the backlog is cleared and all listeners have been informed.
void	notifyFiredProcWaits()
void	pauseFiringNewProcs() Pauses notifications for all consumers until a matching number of resumeFiringNewProcs calls have been made.
boolean	putIntoVirtualProcQueue(BOProc proc) Puts the proc into the explicit queue for non persistent changes or persistent changes that have been applied to the transactions BOs indirectly (e.g. otherTransactionsSaveSuccess).
boolean	putIntoVirtualProcQueue(java.util.List<BOProc> procs) Puts multiple procs into the virtual proc queue
void	registerListener(TransactionListenerI l) Registers a nonnull listener to receive notification on new changes from now on.
void	removeAllListeners()
void	resumeFiringNewProcs() Reduces the number of pause requests created by by one and resumes firing of new procs if no pause requests remain.
java.lang.String	toString()
void	unregisterListener(TransactionListenerI l) Unregisters a nonnull listener, causing that listener to no longer receive notifications.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

MAGIC_WHOLE_BO_ATTRIBUTE

public static final java.lang.String MAGIC_WHOLE_BO_ATTRIBUTE

Attribute'name' used to represent a refresh of all scalars and n-1 relations on the BOProc.

See Also:

Constant Field Values

Constructor Detail

TransactionMessageBus

public TransactionMessageBus(Transaction _tx)

Method Detail

getTransaction

public Transaction getTransaction()

isEventFiringPaused

public boolean isEventFiringPaused()

Specified by:

isEventFiringPaused in interface TransactionMessageBusI

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

public void pauseFiringNewProcs()

Description copied from interface: TransactionMessageBusI

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.

Specified by:

pauseFiringNewProcs in interface TransactionMessageBusI

resumeFiringNewProcs

public void resumeFiringNewProcs()

Description copied from interface: TransactionMessageBusI

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.

Specified by:

resumeFiringNewProcs in interface TransactionMessageBusI

forceResumeFiringNewProcs

public void forceResumeFiringNewProcs()

Ignores previous pauses to event firing by any sources and reenables it

killNewProcsRunner

public static void killNewProcsRunner()

This should only be called if a classloader is disposed of and we need to stop this class's NewProcsRunner!

registerListener

public void registerListener(TransactionListenerI l)

Description copied from interface: TransactionMessageBusI

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

Specified by:

registerListener in interface TransactionMessageBusI

unregisterListener

public void unregisterListener(TransactionListenerI l)

Description copied from interface: TransactionMessageBusI

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

Specified by:

unregisterListener in interface TransactionMessageBusI

removeAllListeners

public void removeAllListeners()

doSignalProcListeners

public void doSignalProcListeners()

fireCheckPoint

public void fireCheckPoint()

newProcSync

public void newProcSync()

Description copied from interface: TransactionMessageBusI

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?

Specified by:

newProcSync in interface TransactionMessageBusI

notifyFiredProcWaits

public void notifyFiredProcWaits()

isAcceptingMessages

public boolean isAcceptingMessages()

Returns:

true if this message bus can consume and notify listeners of changes, false if the message bus is inactive. When inactive, the message bus will drop and silently ignore all message requests.

fireNewProcs

public void fireNewProcs()

Notify the NewProcsRunner thread that this MessageBus has new messages to handle. Won't notify if paused.

enableSynchronousEventsForUnittests

public void enableSynchronousEventsForUnittests()

New Events will trigger a notification of listeners directly, in the thread that triggered the event, skipping the asynchronous event collection behaviour. It's intended usage are unit tests which need to react on events.

disableSynchronousEventsForUnittests

public void disableSynchronousEventsForUnittests()

Disable synchronous events again. This is the default behaviour

consumeScriptedAttributeChange

public static void consumeScriptedAttributeChange(SetValueEventI changeEvent)

This method will call consumeAfterSetMessage on the MessageBus for the BOs loadingTransaction. It should be used to generate the default callback for ScriptedAttribute changes, as it can handle BOs from cascaded InstrumentedSchemas as well.

consumeAfterSetMessage

public void consumeAfterSetMessage(SetValueEventI changeEvent)

Specified by:

consumeAfterSetMessage in interface TransactionMessageBusI

createAfterSetMessage

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

Specified by:

createAfterSetMessage in interface TransactionMessageBusI

createAfterSetMessage

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

Description copied from interface: TransactionMessageBusI

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.

Specified by:

createAfterSetMessage in interface TransactionMessageBusI

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)

createAfterAddMessage

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

Specified by:

createAfterAddMessage in interface TransactionMessageBusI

createAfterRemoveMessage

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

Specified by:

createAfterRemoveMessage in interface TransactionMessageBusI

putIntoVirtualProcQueue

public boolean putIntoVirtualProcQueue(BOProc proc)

Puts the proc into the explicit queue for non persistent changes or persistent changes that have been applied to the transactions BOs indirectly (e.g. otherTransactionsSaveSuccess). Will not fill the queue if either there is either no one listening or the proc trigger that consumes the queue is not running due to being headless.

Parameters:

proc - the proc to put into the virtual queue, nonnull.

Returns:

true if the proc has been queued, false if not.

putIntoVirtualProcQueue

public boolean putIntoVirtualProcQueue(java.util.List<BOProc> procs)

Puts multiple procs into the virtual proc queue

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object