/*
 * Copyright 1997-2008 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 */

package javax.media.j3d;

import java.util.Enumeration;

/**
 * An abstract class specifying a single wakeup Condition. This class
 * is extended by the WakeupCriterion, WakeupOr, WakeupAnd,
 * WakeupOrOfAnds, and WakeupAndOfOr classes. A Behavior node hands a
 * WakeupCondition object to the behavior scheduler and the behavior
 * scheduler hands back an enumeration of that WakeupCondition.
 */

public abstract class WakeupCondition extends Object {

    static final int ALL_ELEMENTS = 0;
    static final int TRIGGERED_ELEMENTS = 1;

    /**
     * This boolean indicates whether this condition has been fully met.
     */
    boolean conditionMet = false;

    /**
     * This points to the parent of this criterion in the AndOr tree
     */
    WakeupCondition parent = null;

    /**
     * The location of this criterion in the parents array.
     */
    int id;

    /**
     * The BehaviorRetained node that is using this condition
     */
    BehaviorRetained behav = null;

    /**
     * This is the allElements enumerator
     */
    WakeupCriteriaEnumerator allEnum = null;

    /**
     * This is the triggeredElements enumerator
     */
    WakeupCriteriaEnumerator trigEnum = null;

    // Use in WakeupIndexedList
    int listIdx[][];

    /**
     * Returns an enumeration of all WakeupCriterias in this Condition.
     */
    public Enumeration allElements() {
	if (allEnum == null) {
	    allEnum = new WakeupCriteriaEnumerator(this, ALL_ELEMENTS);
	} else {
	    allEnum.reset(this, ALL_ELEMENTS);
	}
	return allEnum;
    }

    /**
     * Returns an enumeration of all triggered WakeupCriterias in this Condition.
     */
    public Enumeration triggeredElements() {
	if (trigEnum == null) {
	    trigEnum = new WakeupCriteriaEnumerator(this, TRIGGERED_ELEMENTS);
	} else {
	    trigEnum.reset(this, TRIGGERED_ELEMENTS);
	}
	return trigEnum;
    }

    /**
     * this sets the conditionMet flag.
     */
    void setConditionMet(int id, Boolean checkSchedulingRegion) {

	if (!conditionMet) {
	    conditionMet = true;
	    J3dMessage message = new J3dMessage();
	    message.type = J3dMessage.COND_MET;
	    message.threads = J3dThread.UPDATE_BEHAVIOR;
	    message.universe = behav.universe;
	    message.args[0] = behav;
	    message.args[1] = checkSchedulingRegion;
	    message.args[2] = this;
	    VirtualUniverse.mc.processMessage(message);
	}
    }

    /**
     * Initialize And/Or tree and add criterion to the BehaviourStructure
     */
    void buildTree(WakeupCondition parent, int id, BehaviorRetained b){
	this.parent = parent;
	this.behav = b;
	this.id = id;
	conditionMet = false;
    }

    /**
     * This goes through the AndOr tree to remove the various criterion from the
     * BehaviorStructure.
     * We can't use  behav.universe.behaviorStructure since behav
     * may reassign to another universe at this time.
     */
    void cleanTree(BehaviorStructure bs) {
	conditionMet = false;
    }

    void reInsertElapseTimeCond() {
	conditionMet = false;
    }

    void resetTree() {
	conditionMet = false;
    }
}