org.apache.commons.scxml
Class SCXMLHelper

java.lang.Object
  |
  +--org.apache.commons.scxml.SCXMLHelper

public final class SCXMLHelper

extends Object

Helper class, all methods static final.

Method Summary

static void	cloneDatamodel(Datamodel datamodel, Context ctx, Evaluator evaluator, org.apache.commons.logging.Log log) Clone data model.
static Set	getAncestorClosure(Set states, Set upperBounds) Creates a set which contains given states and all their ancestors recursively up to the upper bound.
static TransitionTarget	getLCA(TransitionTarget tt1, TransitionTarget tt2) Finds the least common ancestor of transition targets tt1 and tt2 if one exists.
static String	getNodeValue(Node node) Retrieve a DOM node value as a string depending on its type.
static Set	getStatesExited(Transition t, Set currentStates) Returns the set of all states (and parallels) which are exited if a given transition t is going to be taken.
static boolean	implementationOf(Class clas, Class interfayce) Whether the class implements the interface.
static boolean	inConflict(Transition t1, Transition t2, Set currentStates) According to the UML definition, two transitions are conflicting if the sets of states they exit overlap.
static boolean	isDescendant(TransitionTarget tt, TransitionTarget ctx) Checks whether a transition target tt (State or Parallel) is a descendant of the transition target context.
static boolean	isLegalConfig(Set states, ErrorReporter errRep) Checks whether a given set of states is a legal Harel State Table configuration (with the respect to the definition of the OR and AND states).
static boolean	isStringEmpty(String attr) Return true if the string is empty.
static void	setNodeValue(Node node, String value) Set node value, depending on its type, from a String.
static boolean	subtypeOf(Class child, Class parent) Whether the first argument is a subtype of the second.

Methods inherited from class java.lang.Object

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

Method Detail

isStringEmpty

public static boolean isStringEmpty(String attr)

Return true if the string is empty.

Parameters:

attr - The String to test

Returns:

Is string empty

isDescendant

public static boolean isDescendant(TransitionTarget tt,
                                   TransitionTarget ctx)

Checks whether a transition target tt (State or Parallel) is a descendant of the transition target context.

Parameters:

tt - TransitionTarget to check - a potential descendant

ctx - TransitionTarget context - a potential ancestor

Returns:

true iff tt is a descendant of ctx, false otherwise

getAncestorClosure

public static Set getAncestorClosure(Set states,
                                     Set upperBounds)

Creates a set which contains given states and all their ancestors recursively up to the upper bound. Null upperBound means root of the state machine.

Parameters:

states - The Set of States

upperBounds - The Set of upper bound States

Returns:

transitive closure of a given state set

isLegalConfig

public static boolean isLegalConfig(Set states,
                                    ErrorReporter errRep)

Checks whether a given set of states is a legal Harel State Table configuration (with the respect to the definition of the OR and AND states).

Parameters:

states - a set of states

errRep - ErrorReporter to report detailed error info if needed

Returns:

true if a given state configuration is legal, false otherwise

getLCA

public static TransitionTarget getLCA(TransitionTarget tt1,
                                      TransitionTarget tt2)

Finds the least common ancestor of transition targets tt1 and tt2 if one exists.

Parameters:

tt1 - First TransitionTarget

tt2 - Second TransitionTarget

Returns:

closest common ancestor of tt1 and tt2 or null

getStatesExited

public static Set getStatesExited(Transition t,
                                  Set currentStates)

Returns the set of all states (and parallels) which are exited if a given transition t is going to be taken. Current states are necessary to be taken into account due to orthogonal states and cross-region transitions - see UML specs for more details.

Parameters:

t - transition to be taken

currentStates - the set of current states (simple states only)

Returns:

a set of all states (including composite) which are exited if a given transition is taken

inConflict

public static boolean inConflict(Transition t1,
                                 Transition t2,
                                 Set currentStates)

According to the UML definition, two transitions are conflicting if the sets of states they exit overlap.

Parameters:

t1 - a transition to check against t2

t2 - a transition to check against t1

currentStates - the set of current states (simple states only)

Returns:

true if the t1 and t2 are conflicting transitions

See Also:

getStatesExited(Transition, Set)

subtypeOf

public static boolean subtypeOf(Class child,
                                Class parent)

Whether the first argument is a subtype of the second.

Parameters:

child - The candidate subtype

parent - The supertype

Returns:

true if child is subtype of parent, otherwise false

implementationOf

public static boolean implementationOf(Class clas,
                                       Class interfayce)

Whether the class implements the interface.

Parameters:

clas - The candidate class

interfayce - The interface

Returns:

true if clas implements interfayce, otherwise false

setNodeValue

public static void setNodeValue(Node node,
                                String value)

Set node value, depending on its type, from a String.

Parameters:

node - A Node whose value is to be set

value - The new value

getNodeValue

public static String getNodeValue(Node node)

Retrieve a DOM node value as a string depending on its type.

Parameters:

node - A node to be retreived

Returns:

The value as a string

cloneDatamodel

public static void cloneDatamodel(Datamodel datamodel,
                                  Context ctx,
                                  Evaluator evaluator,
                                  org.apache.commons.logging.Log log)

Clone data model.

Parameters:

ctx - The context to clone to.

datamodel - The datamodel to clone.

evaluator - The expression evaluator.

log - The error log.