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/*
 * Copyright © 1996-2009 GlobalMentor, Inc. 
 *
 * 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 com.globalmentor.swing;

import java.awt.event.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.event.EventListenerList;

/**
 * Class that fires action events when an item is double-clicked or the Enter key is pressed. This class will be superceded if a future version of {@link JList}
 * handles these key/mouse bindings for the correct UI.
 * 
 * This class was created from consulting the JDK 1.3.1 API documentation for {@link JList} and {@link JButton}, along with the sample ActionJList
 * code at http://www.rgagnon.com/javadetails/java-0201.html.
 * 
 * @author Garret Wilson
 */
public class ActionList extends JList {

	/** The key for mapping the action-firing action in the input and action maps. */
	public static final String ACTION_KEY = "action";

	/** The list of action listeners. */
	protected final EventListenerList actionListenerList = new EventListenerList();

	/**
	 * Constructs a list that displays the elements in the specified, non-null model.
	 * @param dataModel The data model for this list.
	 * @throws IllegalArgumentException Thrown if dataModel is null.
	 */
	public ActionList(final ListModel dataModel) {
		super(dataModel); //delegate to the parent class
		addListeners(); //add the listeners needed for generating action events in response
	}

	/**
	 * Constructs a list that displays the elements in the specified array.
	 * @param listData The array of objects to be loaded into the data model.
	 */
	public ActionList(final Object[] listData) {
		super(listData); //delegate to the parent class
		addListeners(); //add the listeners needed for generating action events in response
	}

	/**
	 * Constructs a list that displays the elements in the specified Vector.
	 * @param listData The Vector to be loaded into the data model.
	 */
	public ActionList(final Vector listData) {
		super(listData); //delegate to the parent class
		addListeners(); //add the listeners needed for generating action events in response
	}

	/** Constructs a list with an empty model. */
	public ActionList() {
		super(); //delegate to the parent class
		addListeners(); //add the listeners needed for generating action events in response
	}

	/** Adds the appropriate listeners for generating actions. */
	private void addListeners() {
		addMouseListener(new MouseAdapter() { //create a new mouse adapter and add it as a listener

			public void mouseClicked(final MouseEvent mouseEvent) {
				if(mouseEvent.getClickCount() == 2) { //if this was a double click
					if(mouseEvent.getSource() instanceof JList) { //if the click originated in a list
						final JList list = (JList)mouseEvent.getSource(); //get the list the click originated in
						final int clickedIndex = list.locationToIndex(mouseEvent.getPoint()); //find the index of the list that was clicked
						if(clickedIndex >= 0) { //if they clicked on a valid index
							final int selectedIndex = list.getSelectedIndex(); //see which index is selected
							if(clickedIndex == selectedIndex) { //if they clicked on the selected index (without checking, double-clicking somewhere else on the list would fire the action)
								fireActionPerformed(); //fire an action performed event
								mouseEvent.consume(); //consume the mouse event TODO do we need this?
							}
						}
					}
				}
			}
		});
		final InputMap inputMap = getInputMap(); //get the input map		
		final ActionMap actionMap = getActionMap(); //get the action map		
		final KeyStroke enterKeyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0); //get the keystroke for the Enter key
		inputMap.put(enterKeyStroke, ACTION_KEY); //map the Enter keystroke to the action key 
		actionMap.put(ACTION_KEY, new ActionAction()); //map the action key to an action-firing action
	}

	/**
	 * Notifies all listeners that have registered interest for notification on this event type.
	 * @see EventListenerList
	 */
	protected void fireActionPerformed() {
		final Object[] selectedValues = getSelectedValues(); //get the selected values
		if(selectedValues.length == 1) { //if there is only one value selected TODO fix for multiple values
			//create a new action event and fire it to the listeners
			fireActionPerformed(new ActionEvent(this, ActionEvent.ACTION_PERFORMED, selectedValues[0].toString()));
		}
	}

	/**
	 * Adds an ActionListener to the list.
	 * @param actionListener The ActionListener to be added.
	 */
	public void addActionListener(final ActionListener actionListener) {
		listenerList.add(ActionListener.class, actionListener);
	}

	/**
	 * Removes an ActionListener from the list.
	 * @param actionListener the listener to be removed
	 */
	public void removeActionListener(final ActionListener actionListener) {
		listenerList.remove(ActionListener.class, actionListener);
	}

	/**
	 * Notifies all listeners that have registered interest for notification on this event type. The event instance is lazily created using the parameters passed
	 * into the fire method.
	 * @param actionEvent The ActionEvent object.
	 * @see EventListenerList
	 */
	protected void fireActionPerformed(final ActionEvent actionEvent) {
		final Object[] listeners = listenerList.getListenerList(); //get the array of listeners
		ActionEvent fireActionEvent = null; //we won't create an action event
		//process the listeners last to first, notifying those that are interested in this event
		for(int i = listeners.length - 2; i >= 0; i -= 2) { //look at all the listener types
			if(listeners[i] == ActionListener.class) { //if this is an action listener
				if(fireActionEvent == null) { //if we haven't yet created an event to fire
					final String actionCommand = actionEvent.getActionCommand(); //get the passed action command
					fireActionEvent = new ActionEvent(ActionList.this, ActionEvent.ACTION_PERFORMED, actionCommand, actionEvent.getModifiers()); //create a new event for firing, using the parameters of the passed event
				}
				((ActionListener)listeners[i + 1]).actionPerformed(fireActionEvent); //send the event to this listener
			}
		}
	}

	/**
	 * Action for firing an action event
	 * @author Garret Wilson
	 */
	protected class ActionAction extends AbstractAction {

		public void actionPerformed(final ActionEvent actionEvent) {
			fireActionPerformed();
		} //fire a new action
	}

}