/*
 * 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 Action may be associated with a transition between to 
states.  The transition action doIt method is called
before the transition takes place.
Author:
Ken Cavanaugh/** An Action may be associated with a transition between to 
 * states.  The transition action doIt method is called
 * before the transition takes place.
 *
 * @author Ken Cavanaugh
 */
public interface Action {
    
Called by the state engine to perform an action
before a state transition takes place.  The FSM is 
passed so that the Action may examine the state of
the FSM.   Note that an
action should complete in a timely manner.  If the state machine
is used for concurrency control with multiple threads, the
action must not allow multiple threads to run simultaneously
in the state machine, as the state could be corrupted.
Any exception thrown by the Action for the transition
will be propagated to doIt.  
Params:
fsm – is the state machine causing this action.
in – is the input that caused the transition./** Called by the state engine to perform an action
    * before a state transition takes place.  The FSM is 
    * passed so that the Action may examine the state of
    * the FSM.   Note that an
    * action should complete in a timely manner.  If the state machine
    * is used for concurrency control with multiple threads, the
    * action must not allow multiple threads to run simultaneously
    * in the state machine, as the state could be corrupted.
    * Any exception thrown by the Action for the transition
    * will be propagated to doIt.  
    * @param fsm is the state machine causing this action.
    * @param in is the input that caused the transition.
    */
    public void doIt( FSM fsm, Input in ) ;

    public abstract class Base extends NameBase implements Action {
	public static Action compose( final Action arg1, final Action arg2 ) {
	    return new Base( 
		"compose(" + arg1.toString() + "," + arg2.toString() + ")" ) {

                @Override
		public void doIt( final FSM fsm, final Input in ) {
		    arg1.doIt( fsm, in ) ;
		    arg2.doIt( fsm, in ) ;
		}
	    } ;
	}

	public Base( String name ) { super( name ) ; } 
    }
}

// end of Action.java