alma.acs.nc.sm.generic

Class AcsScxmlActionDispatcher<A extends java.lang.Enum<A>>

java.lang.Object

alma.acs.nc.sm.generic.AcsScxmlActionDispatcher<A>

Type Parameters:

A - The SM action enumeration.

public class AcsScxmlActionDispatcher<A extends java.lang.Enum<A>>
extends java.lang.Object

The user-supplied dispatcher that will be invoked by an instance of AcsScxmlDispatchingAction, thus bringing action handlers under user control instead of using directly the handler instantiated by the SCXML framework.

Handlers must be registered using registerActionHandler(Enum, AcsScxmlActionExecutor).

Author:

hsommer

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	AcsScxmlActionDispatcher.ActionExceptionHandler

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	CUSTOM_ACTIONS_DOMAIN_NAME
protected java.util.logging.Logger	logger

Constructor Summary

Constructors

Constructor and Description
AcsScxmlActionDispatcher(java.util.logging.Logger logger, java.lang.Class<A> actionType)

Method Summary

Modifier and Type	Method and Description
void	execute(A action, EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance, java.util.Collection<TriggerEvent> derivedEvents) Generic action handler, dispatches to the right handler based on action type.
AcsScxmlActionExecutor<A>	getActionHandler(A action) An alternative to execute(Enum, EventDispatcher, ErrorReporter, SCInstance, Collection) where the handler can be accessed and stored directly.
java.lang.Class<A>	getActionType() Used by an AcsScxmlDispatchingAction object to convert its action name to the corresponding enum value.
protected java.util.List<CustomAction>	getScxmlActionMap() Wraps the registered action handlers in a form suitable for the SCXML framework.
boolean	isActionMappingComplete() Checks whether all action enums have an action handler registered.
void	registerActionHandler(A action, AcsScxmlActionExecutor<A> handler) Registers an action handler for the given SM action.
void	setActionExceptionHandler(AcsScxmlActionDispatcher.ActionExceptionHandler handler)

Methods inherited from class java.lang.Object

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

Field Detail

CUSTOM_ACTIONS_DOMAIN_NAME

public static final java.lang.String CUSTOM_ACTIONS_DOMAIN_NAME

See Also:

Constant Field Values

logger

protected final java.util.logging.Logger logger

Constructor Detail

AcsScxmlActionDispatcher

public AcsScxmlActionDispatcher(java.util.logging.Logger logger,
                                java.lang.Class<A> actionType)

Method Detail

execute

public void execute(A action,
                    EventDispatcher evtDispatcher,
                    ErrorReporter errRep,
                    SCInstance scInstance,
                    java.util.Collection<TriggerEvent> derivedEvents)
             throws ModelException,
                    SCXMLExpressionException

Generic action handler, dispatches to the right handler based on action type.

TODO: org.apache.commons.scxml.env.SimpleErrorReporter#onError prints the class name of the "Object errCtx". Currently we'd get NPE or useless info.

Throws:

ModelException

SCXMLExpressionException

getActionHandler

public AcsScxmlActionExecutor<A> getActionHandler(A action)

An alternative to execute(Enum, EventDispatcher, ErrorReporter, SCInstance, Collection) where the handler can be accessed and stored directly. Using this approach may bring a tiny performance advantage, but probably should be removed again..

registerActionHandler

public void registerActionHandler(A action,
                                  AcsScxmlActionExecutor<A> handler)

Registers an action handler for the given SM action. Note that the same handler object can be registered for one or many actions, so that we are flexible in how we implement the handlers.

Parameters:

action -

handler -

isActionMappingComplete

public boolean isActionMappingComplete()

Checks whether all action enums have an action handler registered.

This method can be used to validate early at runtime that no action goes without handler, which might happen after a change in the SM model.

Note that this kind of completeness check could also be done at build time using an action enum with visitor pattern, see http://raginggoblin.wordpress.com/2010/06/10/switch-over-all-values-of-a-java-enum/. However, this would require us to dispatch all actions through a single interface that has a typed method per action and whose implementation could then of course dispatch further to various objects. For the time being we stay with the looser coupling of registering various action handler objects and validating them for completeness early at runtime (not waiting until some rare action finally occurs).

Returns:

true if for all SM actions we have a registered handler.

getActionType

public java.lang.Class<A> getActionType()

Used by an AcsScxmlDispatchingAction object to convert its action name to the corresponding enum value. (This type information cannot be passed directly because Apache SCXML creates the action with an empty constructor.)

getScxmlActionMap

protected java.util.List<CustomAction> getScxmlActionMap()

Wraps the registered action handlers in a form suitable for the SCXML framework. The framework will instantiate DispatchingScxmlAction for each action, which will then call back to execute(Enum, EventDispatcher, ErrorReporter, SCInstance, Collection).

Returns:

setActionExceptionHandler

public void setActionExceptionHandler(AcsScxmlActionDispatcher.ActionExceptionHandler handler)