AbstractRuleElement.java

/*
 * ====================================================================
 * 
 * The ObjectStyle Group Software License, Version 1.0
 * 
 * Copyright (c) 2005 The ObjectStyle Group and individual authors of the
 * software. All rights reserved.
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 * include the following acknowlegement: "This product includes software
 * developed by the ObjectStyle Group (http://objectstyle.org/)." Alternately,
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package org.objectstyle.wolips.ruleeditor.model;

import java.beans.*;
import java.util.*;

/**
 * This class is an abstraction with the basic properties of a rule element.
 * Every element of a rule should extends this class.
 * 
 * @author uli
 * @author <a href="mailto:frederico@moleque.com.br">Frederico Lellis</a>
 * @author <a href="mailto:georg@moleque.com.br">Georg von Bülow</a>
 * @author <a href="mailto:hprange@moleque.com.br">Henrique Prange</a>
 */
public abstract class AbstractRuleElement {
	protected static final String CLASS_KEY = "class";

	private String assignmentClassName;

	private final PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);

	/**
	 * The constructor is protected because the creation of rule elements should
	 * be done by a <code>Rule</code> object.
	 * 
	 * @param properties
	 *            A map describing this element
	 */
	protected AbstractRuleElement(final Map<String, Object> properties) {
		if (properties == null) {
			throw new IllegalArgumentException("The properties Map of this model element cannot be null");
		}

		assignmentClassName = (String) properties.get(CLASS_KEY);
	}

	public void addPropertyChangeListener(PropertyChangeListener listener) {
		propertyChangeSupport.addPropertyChangeListener(listener);
	}

	protected void firePropertyChange(PropertyChangeEvent event) {
		propertyChangeSupport.firePropertyChange(event);
	}

	protected void firePropertyChange(String propertyName, Object oldValue, Object newValue) {
		propertyChangeSupport.firePropertyChange(propertyName, oldValue, newValue);
	}

	public String getAssignmentClassName() {
		return assignmentClassName;
	}

	public void removePropertyChangeListener(PropertyChangeListener listener) {
		propertyChangeSupport.removePropertyChangeListener(listener);
	}

	public void setAssignmentClassName(final String className) {
		String oldValue = assignmentClassName;

		assignmentClassName = className;

		firePropertyChange(CLASS_KEY, oldValue, assignmentClassName);
	}

	/**
	 * Subclasses of <code>AbstractRuleElement</code> must implement this
	 * method and return a Map describing it using the key-value pattern.
	 * 
	 * @return A <code>Map</code> describing the rule element
	 */
	protected abstract Map<String, Object> toMap();
}