conditionalaction.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as 
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version. 
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.gui;

import java.util.List;
import java.util.LinkedList;
import java.util.Iterator;

import javax.swing.Icon;
import javax.swing.AbstractAction; 

/** An action that must be enabled/disabled depending on certain conditions. 
 *  These conditions can be mandatrory, disallowed, or irrelevant. All ConditionalActions created are 
 *  added to a collection. */
public abstract class ConditionalAction extends AbstractAction {

    private static final List ALL_ACTIONS = new LinkedList();

    public static final int DISALLOWED = -1;
    public static final int DONT_CARE  = 0;
    public static final int MANDATORY  = 1;

    public static final int OPERATOR_SELECTED       = 0;
    public static final int OPERATOR_CHAIN_SELECTED = 1;
    public static final int ROOT_SELECTED = 2;
    public static final int CLIPBOARD_FILLED = 3;
    public static final int EXPERIMENT_RUNNING = 4;

    public static final int NUMBER_OF_CONDITIONS = 5;

    private int[] conditions = new int[NUMBER_OF_CONDITIONS];

    public ConditionalAction(String name) {
	this(name, null);
    }

    public ConditionalAction(String name, Icon icon) {
	super(name, icon);
	ALL_ACTIONS.add(this);
    }

    /** @param index one out of OPERATOR_SELECTED, OPERATOR_CHAIN_SELECTED, ROOT_SELECTED, CLIPBOARD_FILLED, and EXPERIMEN_RUNNING
     *  @param condition one out of DISALLOWED, DONT_CARE, and MANDATORY
     */
    public void setCondition(int index, int condition) {
	conditions[index] = condition;
    }

    /** Updates all actions. */
    public static void updateAll(boolean[] states) {
	Iterator i = ALL_ACTIONS.iterator();
	while (i.hasNext()) {
	    ((ConditionalAction)i.next()).update(states);
	}
    }

    /** Updates an action given the set of states that can be true or false. States refer to OPERATOR_SELECTED...
     *  An action is enabled iff for all states the condition is DONT_CARE or MANDATORY and state is true or
     *  DISALLOWED and state is false. */
    private void update(boolean[] state) {
	boolean ok = true;
	for (int i = 0; i < conditions.length;i++) {
	    if (conditions[i] != DONT_CARE) {
		if (((conditions[i] == MANDATORY) && (state[i] == false)) ||
		    ((conditions[i] == DISALLOWED) && (state[i] == true))) {
		    ok = false;
		    break;
		}		
	    }
	}
	setEnabled(ok);
    }
}