ca.uqac.lif.ecp.statechart

Class Transition<T extends Event>

java.lang.Object

ca.uqac.lif.ecp.statechart.Transition<T>

Type Parameters:

T - The type of the event on the transition

Direct Known Subclasses:

AtomicTransition, TrashTransition

public abstract class Transition<T extends Event>
extends java.lang.Object

A transition from a state to another in a statechart

Author:

Sylvain Hallé

Field Summary

Fields

Modifier and Type	Field and Description
protected Action<T>	m_action The action associated to this transition.
protected Operator<T>	m_guard A Boolean expression
protected Configuration<T>	m_target The target of this transition

Constructor Summary

Constructors

Constructor and Description
Transition() Creates a new empty transition

Method Summary

Modifier and Type	Method and Description
protected abstract boolean	afterGuard(T event, Statechart<T> statechart) Checks whether a transition fires, after the guard on that transition has been evaluated.
abstract Transition<T>	clone()
void	executeAction(T event, Statechart<T> statechart) Executes the action associated to this transition, if one is defined
Action<T>	getAction() Gets the action associated to this transition
Operator<T>	getGuard() Gets the guard associated to this transition
Configuration<T>	getTarget() Gets the target of this transition
protected boolean	hasSameParameters(Transition<T> t) Checks that this transition has the same parameters (guard, action, target) as another one
boolean	matches(T event, Statechart<T> statechart) Determines if this transition applies (i.e.
Transition<T>	setAction(Action<T> action) Associates an action to this transition
Transition<T>	setGuard(Operator<T> guard) Associates a guard to this transition

Methods inherited from class java.lang.Object

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

Field Detail

m_target

protected Configuration<T extends Event> m_target

The target of this transition

m_action

protected Action<T extends Event> m_action

The action associated to this transition. Actions are optional.

m_guard

protected Operator<T extends Event> m_guard

A Boolean expression

Constructor Detail

Transition

public Transition()

Creates a new empty transition

Parameters:

statechart - The statechart this transition belongs to

Method Detail

matches

public final boolean matches(T event,
                             Statechart<T> statechart)

Determines if this transition applies (i.e. fires) on the event given as input

Parameters:

event - The event

statechart - The statechart this transition belongs to

Returns:

true if the transition fires, false otherwise

afterGuard

protected abstract boolean afterGuard(T event,
                                      Statechart<T> statechart)

Checks whether a transition fires, after the guard on that transition has been evaluated. This method is only called if the guard on that transition evaluates to true.

Parameters:

event - The event

statechart - The statechart this transition belongs to

Returns:

true if the transition fires, false otherwise

clone

public abstract Transition<T> clone()

Overrides:

clone in class java.lang.Object

getTarget

public Configuration<T> getTarget()

Gets the target of this transition

Returns:

A configuration

hasSameParameters

protected boolean hasSameParameters(Transition<T> t)

Checks that this transition has the same parameters (guard, action, target) as another one

Parameters:

t - The other transition

Returns:

true if the transition has the same parameters, false otherwise

setAction

public Transition<T> setAction(Action<T> action)

Associates an action to this transition

Parameters:

action - An action. May be null; in such a case, deletes any action already associated to the transition.

Returns:

This transition

setGuard

public Transition<T> setGuard(Operator<T> guard)

Associates a guard to this transition

Parameters:

action - An guard. May be null; in such a case, deletes any guard already associated to the transition.

Returns:

This transition

executeAction

public void executeAction(T event,
                          Statechart<T> statechart)
                   throws ActionException

Executes the action associated to this transition, if one is defined

Parameters:

event - The event that fired this transition

statechart - The statechart this transition belongs to

Throws:

ActionException

getGuard

public Operator<T> getGuard()

Gets the guard associated to this transition

Returns:

The guard, or null if no guard is defined

getAction

public Action<T> getAction()

Gets the action associated to this transition

Returns:

The action, or null if no action is defined