org.glassfish.pfl.basic.fsm.FSM Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2018 Oracle and/or its affiliates. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Distribution License v. 1.0, which is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
package org.glassfish.pfl.basic.fsm ;
/**
* An FSM is used to represent an instance of a finite state machine
* which has a transition function represented by an instance of
* StateEngine. An instance of an FSM may be created either by calling
* StateEngine.makeFSM( startState ) on a state engine, or by extending FSMImpl and
* using a constructor. Using FSMImpl as a base class is convenient if
* additional state is associated with the FSM beyond that encoded
* by the current state. This is especially convenient if an action
* needs some additional information. For example, counters are best
* handled by special actions rather than encoding a bounded counter
* in a state machine. It is also possible to create a class that
* implements the FSM interface by delegating to an FSM instance
* created by StateEngine.makeFSM.
*
* @author Ken Cavanaugh
*/
public interface FSM
{
/** Return the state engine used to create this FSM.
*/
public StateEngine getStateEngine() ;
/** Get the parent state machine.
*/
public FSM getParent() ;
/** Set the parent state machine.
*/
public void setParent( FSM fsm ) ;
/** Set the current state of this FSM. May not be called
* inside a transition action, or from a State method.
* Only here for use by the StateEngine.
*/
public void setState( State state ) ;
/** Get the current state of this FSM.
*/
public State getState() ;
}
// end of FSM.java