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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.Component;
import java.awt.KeyboardFocusManager;
import javax.swing.*;

/**
 * Action that considers the focused component as its target.
 * 
 * In this version, {@link FocusTargetAction#setTarget(Object)} sets the default target for the situation in which there is no focus owner.
 * 
 * @author Garret Wilson
 */
public abstract class FocusTargetAction extends TargetAction {

	/**
	 * Determines the target of the action.
	 * 
	 * This version checks to see if any component owns the focus. If so, that component is returns. If not, the default target is returned.
	 * 
	 * @return The current focus owner component, or the default target of the action if there is no focus owner, or null if there is no default
	 *         target.
	 * @see #getFocusOwner()
	 * */
	public Object getTarget() {
		final Component focusOwner = getFocusOwner(); //get the current focus owner
		return focusOwner != null ? focusOwner : super.getTarget(); //return the focus owner or the default target
	}

	/**
	 * Gets the current focus owner.
	 * 
	 * If a derived class wants to only recognize certain focused targets, it should override this method and return null if the currently focused
	 * component is not of the correct type.
	 * 
	 * @return The current focus owner, or null if there is no current focus owner.
	 * @see KeyboardFocusManager#getFocusOwner()
	 */
	protected Component getFocusOwner() {
		return KeyboardFocusManager.getCurrentKeyboardFocusManager().getFocusOwner(); //return the current focus owner
	}

	/** Default constructor with no default target. */
	public FocusTargetAction() {
		super(); //construct the parent
	}

	/**
	 * Name constructor with no default target.
	 * @param name The name description of the action.
	 */
	public FocusTargetAction(final String name) {
		super(name); //construct the parent
	}

	/**
	 * Name and target constructor.
	 * @param name The name description of the action.
	 * @param defaultTarget The default target component, or null if there should be no default target.
	 */
	public FocusTargetAction(final String name, final Component defaultTarget) {
		super(name, defaultTarget); //construct the parent
	}

	/**
	 * Name and icon constructor with no default target.
	 * @param name The name description of the action.
	 * @param icon The icon to represent the action.
	 */
	public FocusTargetAction(final String name, final Icon icon) {
		super(name, icon); //construct the parent
	}

	/**
	 * Name, icon, and default target constructor.
	 * @param name The name description of the action.
	 * @param icon The icon to represent the action.
	 * @param defaultTarget The default target component, or null if there should be no default target.
	 */
	public FocusTargetAction(final String name, final Icon icon, final Component defaultTarget) {
		super(name, icon, defaultTarget); //construct the parent
	}

}