src/org/apache/taglibs/rdc/scxml/model/History.java

/*
 *    
 *   Copyright 2004 The Apache Software Foundation.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.taglibs.rdc.scxml.model;

import java.util.HashSet;
import java.util.Set;

/**
 * The class in this SCXML object model that corresponds to the
 * <history> SCXML pseudo state element.
 * 
 * @author Rahul Akolkar
 * @author Jaroslav Gergic
 */
public class History extends TransitionTarget {
    
	/**
     * Whether this is a shallow or deep history, the default is shallow.
     */
	private boolean isDeep;

    /**
     * A conditionless transition representing the default history state 
     * and indicates the state to transition to if the parent state has 
     * never been entered before.
     */
	private Transition transition;
	
    /**
     * The configuration when the parent of this pseudo state was last
     * exited.
     */
    private Set lastConfiguration;

    /**
	 * Default no-args constructor for XML Digester
	 */
	public History() {
		super();
	}
	
	/**
	 * Get the transition
	 * 
	 * @return Returns the transition.
	 */
	public Transition getTransition() {
		return transition;
	}
	
	/**
	 * Set the transition
	 * 
	 * @param transition The transition to set.
	 */
	public void setTransition(Transition transition) {
		this.transition = transition;
	}
	
	/**
	 * Is this history "deep" (as against "shallow")
	 * 
	 * @return Returns whether this is a "deep" history
	 */
	public boolean isDeep() {
		return isDeep;
	}
	
	/**
	 * This method is invoked by XML digester when parsing SCXML markup
	 * 
	 * @param type The history type, which can be "shallow" or 
	 * "deep"
	 */
	public void setType(String type) {
		if(type.equals("deep")) {
			isDeep = true;
		}
		//shallow is by default
	}
	
	/**
	 * Get the last configuration for this history
	 * 
	 * @return Returns the lastConfiguration.
	 */
	public Set getLastConfiguration() {
		return lastConfiguration;
	}
	
	/**
	 * Set the last configuration for this history
	 * 
	 * @param lc The lastConfiguration to set.
	 */
	public void setLastConfiguration(Set lc) {
		if(this.lastConfiguration == null) {
			this.lastConfiguration = new HashSet(lc.size());
		} else {
			this.lastConfiguration.clear();
		}
		this.lastConfiguration.addAll(lc);
	}
	
	/**
	 * Check whether we have prior history
	 * 
	 * @return Whether we have a non-empty last configuration
	 */
	public boolean isEmpty() {
		return (lastConfiguration == null || lastConfiguration.isEmpty()) ?
				true : false;
	}

}