org.apache.commons.scxml.semantics
Class SCXMLSemanticsImpl

java.lang.Object
  org.apache.commons.scxml.semantics.SCXMLSemanticsImpl

All Implemented Interfaces:

Serializable, SCXMLSemantics

public class SCXMLSemanticsImpl
extends Object
implements SCXMLSemantics, Serializable

This class encapsulates a particular SCXML semantics, that is, a particular semantic interpretation of Harel Statecharts, which aligns mostly with W3C SCXML July 5 public draft (that is, UML 1.5). However, certain aspects are taken from STATEMATE.

Specific semantics can be created by subclassing this class.

See Also:

Serialized Form

Constructor Summary

SCXMLSemanticsImpl()

Method Summary

void	determineInitialStates(SCXML input, Set targets, List entryList, ErrorReporter errRep, SCInstance scInstance) Determining the initial state(s) for this state machine.
void	determineTargetStates(Set states, ErrorReporter errRep, SCInstance scInstance)
void	enumerateReachableTransitions(SCXML stateMachine, Step step, ErrorReporter errRep) Enumerate all the reachable transitions.
protected boolean	eventMatch(String transEvent, Set eventOccurrences) Implements prefix match, that is, if, for example, "mouse.click" is a member of eventOccurrences and a transition is triggered by "mouse", the method returns true.
void	executeActions(Step step, SCXML stateMachine, EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance) Executes all OnExit/Transition/OnEntry transitional actions.
void	filterTransitionsSet(Step step, EventDispatcher evtDispatcher, ErrorReporter errRep, SCInstance scInstance) Filter the transitions set, eliminate those whose guard conditions are not satisfied.
protected boolean	finalizeMatch(String parentStateId, Set eventOccurrences) Implements event prefix match to ascertain <finalize> execution.
void	followTransitions(Step step, ErrorReporter errorReporter, SCInstance scInstance) Follow the candidate transitions for this execution Step, and update the lists of entered and exited states accordingly.
protected org.apache.commons.logging.Log	getLog() Get the log used by this SCXMLSemantics instance.
protected Comparator	getTTComparator() TransitionTargetComparator factory method.
void	initiateInvokes(Step step, ErrorReporter errRep, SCInstance scInstance) Initiate any new invokes.
SCXML	normalizeStateMachine(SCXML input, ErrorReporter errRep) Optional post processing immediately following Digester.
void	processInvokes(TriggerEvent[] events, ErrorReporter errRep, SCInstance scInstance) Process any existing invokes, includes forwarding external events, and executing any finalize handlers.
Set	seedTargetSet(Set residual, List transitList, ErrorReporter errRep) Populate the target set.
protected void	setLog(org.apache.commons.logging.Log log) Set the log used by this SCXMLSemantics instance.
void	updateHistoryStates(Step step, ErrorReporter errRep, SCInstance scInstance) Go over the exit list and update history information for relevant states.

Methods inherited from class java.lang.Object

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

Constructor Detail

SCXMLSemanticsImpl

public SCXMLSemanticsImpl()

Method Detail

normalizeStateMachine

public SCXML normalizeStateMachine(SCXML input,
                                   ErrorReporter errRep)

Description copied from interface: SCXMLSemantics

Optional post processing immediately following Digester. May be used for removing pseudo-states etc.

Specified by:

normalizeStateMachine in interface SCXMLSemantics

Parameters:

input - SCXML state machine

errRep - ErrorReporter callback

Returns:

normalized SCXML state machine, pseudo states are removed, etc.

determineInitialStates

public void determineInitialStates(SCXML input,
                                   Set targets,
                                   List entryList,
                                   ErrorReporter errRep,
                                   SCInstance scInstance)
                            throws ModelException

Description copied from interface: SCXMLSemantics

Determining the initial state(s) for this state machine.

Specified by:

determineInitialStates in interface SCXMLSemantics

Parameters:

input - SCXML state machine [in]

targets - a set of initial targets to populate [out]

entryList - a list of States and Parallels to enter [out]

errRep - ErrorReporter callback [inout]

scInstance - The state chart instance [in]

Throws:

ModelException - in case there is a fatal SCXML object model problem.

executeActions

public void executeActions(Step step,
                           SCXML stateMachine,
                           EventDispatcher evtDispatcher,
                           ErrorReporter errRep,
                           SCInstance scInstance)
                    throws ModelException

Executes all OnExit/Transition/OnEntry transitional actions.

Specified by:

executeActions in interface SCXMLSemantics

Parameters:

step - provides EntryList, TransitList, ExitList gets updated its AfterStatus/Events

stateMachine - state machine - SCXML instance

evtDispatcher - the event dispatcher - EventDispatcher instance

errRep - error reporter

scInstance - The state chart instance

Throws:

ModelException - in case there is a fatal SCXML object model problem.

enumerateReachableTransitions

public void enumerateReachableTransitions(SCXML stateMachine,
                                          Step step,
                                          ErrorReporter errRep)

Description copied from interface: SCXMLSemantics

Enumerate all the reachable transitions.

Specified by:

enumerateReachableTransitions in interface SCXMLSemantics

Parameters:

stateMachine - a SM to traverse [in]

step - with current status and list of transitions to populate [inout]

errRep - ErrorReporter callback [inout]

filterTransitionsSet

public void filterTransitionsSet(Step step,
                                 EventDispatcher evtDispatcher,
                                 ErrorReporter errRep,
                                 SCInstance scInstance)
                          throws ModelException

Description copied from interface: SCXMLSemantics

Filter the transitions set, eliminate those whose guard conditions are not satisfied.

Specified by:

filterTransitionsSet in interface SCXMLSemantics

Parameters:

step - [inout]

evtDispatcher - The EventDispatcher [in]

errRep - ErrorReporter callback [inout]

scInstance - The state chart instance [in]

Throws:

ModelException - in case there is a fatal SCXML object model problem.

seedTargetSet

public Set seedTargetSet(Set residual,
                         List transitList,
                         ErrorReporter errRep)

Populate the target set.

• take targets of selected transitions
• take exited regions into account and make sure every active parallel region has all siblings active [that is, explicitly visit or sibling regions in case of newly visited (revisited) orthogonal states]

Parameters:

residual - [in]

transitList - [in]

errRep - ErrorReporter callback [inout]

Returns:

Set The target set

determineTargetStates

public void determineTargetStates(Set states,
                                  ErrorReporter errRep,
                                  SCInstance scInstance)
                           throws ModelException

Parameters:

states - a set seeded in previous step [inout]

errRep - ErrorReporter callback [inout]

scInstance - The state chart instance [in]

Throws:

ModelException - On illegal configuration

See Also:

seedTargetSet(Set, List, ErrorReporter)

updateHistoryStates

public void updateHistoryStates(Step step,
                                ErrorReporter errRep,
                                SCInstance scInstance)

Go over the exit list and update history information for relevant states.

Specified by:

updateHistoryStates in interface SCXMLSemantics

Parameters:

step - [inout]

errRep - ErrorReporter callback [inout]

scInstance - The state chart instance [inout]

followTransitions

public void followTransitions(Step step,
                              ErrorReporter errorReporter,
                              SCInstance scInstance)
                       throws ModelException

Follow the candidate transitions for this execution Step, and update the lists of entered and exited states accordingly.

Specified by:

followTransitions in interface SCXMLSemantics

Parameters:

step - The current Step

errorReporter - The ErrorReporter for the current environment

scInstance - The state chart instance

Throws:

ModelException - in case there is a fatal SCXML object model problem.

processInvokes

public void processInvokes(TriggerEvent[] events,
                           ErrorReporter errRep,
                           SCInstance scInstance)
                    throws ModelException

Process any existing invokes, includes forwarding external events, and executing any finalize handlers.

Specified by:

processInvokes in interface SCXMLSemantics

Parameters:

events - The events to be forwarded

errRep - ErrorReporter callback

scInstance - The state chart instance

Throws:

ModelException - in case there is a fatal SCXML object model problem.

initiateInvokes

public void initiateInvokes(Step step,
                            ErrorReporter errRep,
                            SCInstance scInstance)

Initiate any new invokes.

Specified by:

initiateInvokes in interface SCXMLSemantics

Parameters:

step - The current Step

errRep - ErrorReporter callback

scInstance - The state chart instance

eventMatch

protected boolean eventMatch(String transEvent,
                             Set eventOccurrences)

Implements prefix match, that is, if, for example, "mouse.click" is a member of eventOccurrences and a transition is triggered by "mouse", the method returns true.

Parameters:

transEvent - a trigger event of a transition

eventOccurrences - current events

Returns:

true/false

finalizeMatch

protected boolean finalizeMatch(String parentStateId,
                                Set eventOccurrences)

Implements event prefix match to ascertain <finalize> execution.

Parameters:

parentStateId - the ID of the parent state of the <invoke> holding the <finalize>

eventOccurrences - current events

Returns:

true/false

getTTComparator

protected Comparator getTTComparator()

TransitionTargetComparator factory method.

Returns:

Comparator The TransitionTarget comparator

setLog

protected void setLog(org.apache.commons.logging.Log log)

Set the log used by this SCXMLSemantics instance.

Parameters:

log - The new log.

getLog

protected org.apache.commons.logging.Log getLog()

Get the log used by this SCXMLSemantics instance.

Returns:

Log The log being used.