editablecombobox.java

一个完整的XACML工程,学习XACML技术的好例子!

/*
* Copyright (c) 2006, University of Kent
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without 
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this 
* list of conditions and the following disclaimer.
* 
* 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. 
*
* 1. Neither the name of the University of Kent nor the names of its 
* contributors may be used to endorse or promote products derived from this 
* software without specific prior written permission. 
*
* 2. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS  
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 
* PURPOSE ARE DISCLAIMED. 
*
* 3. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 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.
*
* 4. YOU AGREE THAT THE EXCLUSIONS IN PARAGRAPHS 2 AND 3 ABOVE ARE REASONABLE
* IN THE CIRCUMSTANCES.  IN PARTICULAR, YOU ACKNOWLEDGE (1) THAT THIS
* SOFTWARE HAS BEEN MADE AVAILABLE TO YOU FREE OF CHARGE, (2) THAT THIS
* SOFTWARE IS NOT "PRODUCT" QUALITY, BUT HAS BEEN PRODUCED BY A RESEARCH
* GROUP WHO DESIRE TO MAKE THIS SOFTWARE FREELY AVAILABLE TO PEOPLE WHO WISH
* TO USE IT, AND (3) THAT BECAUSE THIS SOFTWARE IS NOT OF "PRODUCT" QUALITY
* IT IS INEVITABLE THAT THERE WILL BE BUGS AND ERRORS, AND POSSIBLY MORE
* SERIOUS FAULTS, IN THIS SOFTWARE.
*
* 5. This license is governed, except to the extent that local laws
* necessarily apply, by the laws of England and Wales.
*/

/*
 * EditableComboBox.java - 20/06/06
 */
package issrg.editor2.ifcondition;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Comparator;
import java.util.Vector;
import javax.swing.JComboBox;

/**
 * Creates an instance of a JComboBox, that a user can edit, and when enter
 * is pressed the item is added to the dropdown list.
 *
 * @author Christian Azzopardi
 */
public class EditableComboBox extends JComboBox implements ActionListener, Comparator
{
    
    /** 
     * Creates a new instance of EditableComboBox 
     *
     * @param items     An initial vector of elements we would like to have
     *                  displayed.
     */
    public EditableComboBox(Vector items) 
    {
        super(items);

        this.setEditable(true);
        this.addActionListener(this);   
        this.setActionCommand("this");
        setFocusable(false);
    }
    
    public void actionPerformed(ActionEvent ae)
    {
        this.removeActionListener(this);
        String newSelection = (String)this.getEditor().getItem();
        int numOfItems = this.getItemCount();
        if (newSelection != null && numOfItems == 0)
        {
            this.addItem(newSelection);
            return;
        }
        for (int i = 0; i < numOfItems; i++)
        {
            if (this.getItemAt(i) != null && ((String)this.getItemAt(i)).intern().equals(newSelection))
            {
                return;
            }
        }
        this.addItem(newSelection);
        this.setSelectedItem(newSelection);
        this.addActionListener(this);
        this.setEditable(false);
        this.setEditable(true);
    }
    
   /**
    * Interface method, to compare strings ignoring the case..
    * This could be used to sort the items in the drop down list in an 
    * alphabetical order.
    */
    public int compare(Object o1, Object o2)
    {
        return ((String)o1).compareToIgnoreCase(((String)o2));
    }   
}