src/antidote/org/apache/tools/ant/gui/acs/ACSElement.java

/*
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999, 2000 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Ant", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */
package org.apache.tools.ant.gui.acs;

import com.sun.xml.tree.ElementNode;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeSupport; 

/**
 * Abstract base class for all Ant Construction Set
 * elements. Depends on the JAXP XML library from Sun.
 * 
 * @version $Revision$ 
 * @author Simeon Fitch */
public abstract class ACSElement extends ElementNode {
    /** Name of the 'xmlString' property. */
    public static final String XML_STRING = "xmlString";

    /** Event support. */
    private PropertyChangeSupport _propSupport = null;

	/** 
	 * Default ctor.
	 * 
	 */
    protected ACSElement() {
    }

	/** 
	 * Get the display name of this.
	 * 
	 * @return Display name.
	 */
    public String getDisplayName() {
        return getTagName();
    }

	/** 
	 * Get the XML representation of this.
	 * 
	 * @return XML representation.
	 */
    public String getXMLString() {
        return toString();
    }

	/** 
	 * Set the given attribute.
	 * 
	 * @param name Name of the attribute.
	 * @param value Value of the attribute.
	 */
    public void setAttribute(String name, String value) {
        if(value == null && getAttribute(name).length() != 0) {
            removeAttribute(name);
        }
        else {
            super.setAttribute(name, value);
        }
    }

	/** 
	 * Add a change listener.
	 * 
	 * @param l Listener to add.
	 */
    public void addPropertyChangeListener(PropertyChangeListener l) {
        if(_propSupport == null) {
            _propSupport = new PropertyChangeSupport(this);
        }
        _propSupport.addPropertyChangeListener(l);
    }


	/** 
	 * Remove a change listener
	 * 
	 * @param l Listener to remove.
	 */
    public void removePropertyChangeListener(PropertyChangeListener l) {
        if(_propSupport == null) {
            _propSupport = new PropertyChangeSupport(this);
        }
        _propSupport.removePropertyChangeListener(l);
    }

	/** 
	 * Fire a change event to all listener.
	 * 
	 * @param propName Name of the property.
	 * @param oldValue The old value.
	 * @param newValue The new value.
	 */
    protected void firePropertyChange(
        String propName, Object oldValue, Object newValue) {
        
        if(_propSupport != null) {
            _propSupport.firePropertyChange(propName, oldValue, newValue);
        }
    }
}