/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.dialogs;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * Helper class to save the enable/disable state of a control
 * including all its descendent controls.
 */
public class ControlEnableState {

	/**
	 * List of exception controls (element type: <code>Control</code>); 
	 * <code>null</code> if none.
	 */
	private List exceptions = null;

	/**
	 * List of saved states (element type: <code>ItemState</code>).
	 */
	private List states;

	/**
	 * Internal class for recording the enable/disable state of a
	 * single control.
	 */
	private class ItemState {
		protected Control item;
		protected boolean state;
		public ItemState(Control item, boolean state) {
			this.item = item;
			this.state = state;
		}
		public void restore() {
			if (item != null)
				item.setEnabled(state);
		}
	}
/**
 * Creates a new object and saves in it the current enable/disable
 * state of the given control and its descendents; the controls 
 * that are saved are also disabled.
 *
 * @param w the control
 */
protected ControlEnableState(Control w) {
	this(w, null);
}
/**
 * Creates a new object and saves in it the current enable/disable
 * state of the given control and its descendents except for the 
 * given list of exception cases; the controls that are saved
 * are also disabled.
 *
 * @param w the control
 * @param exceptions the list of controls to not disable
 *  (element type: <code>Control</code>), or <code>null</code> if none
 */
protected ControlEnableState(Control w, List exceptions) {
	super();
	states = new ArrayList();
	this.exceptions = exceptions;
	readStateForAndDisable(w);
}
/**
 * Saves the current enable/disable state of the given control
 * and its descendents in the returned object; the controls
 * are all disabled.
 *
 * @param w the control
 * @return an object capturing the enable/disable state
 */
public static ControlEnableState disable(Control w) {
	return new ControlEnableState(w);
}
/**
 * Saves the current enable/disable state of the given control
 * and its descendents in the returned object except for the 
 * given list of exception cases; the controls that are saved
 * are also disabled.
 *
 * @param w the control
 * @param exceptions the list of controls to not disable
 *  (element type: <code>Control</code>)
 * @return an object capturing the enable/disable state
 */
public static ControlEnableState disable(Control w, List exceptions) {
	return new ControlEnableState(w, exceptions);
}
/**
 * Recursively reads the enable/disable state for the given window
 * and disables all controls.
 */
private void readStateForAndDisable(Control w) {
	if ((exceptions != null && exceptions.contains(w)))
		return;

	if (w instanceof Composite) {
		Composite c = (Composite) w;
		Control[] children = c.getChildren();
		for (int i = 0; i < children.length; i++) {
			readStateForAndDisable(children[i]);
		}
	}
	// XXX: Workaround for 1G2Q8SS: ITPUI:Linux - Combo box is not enabled in "File->New->Solution"
	states.add(new ItemState(w, w.getEnabled()));
	w.setEnabled(false);
}
/**
 * Restores the window enable state saved in this object.
 */
public void restore() {
	int size = states.size();
	for (int i = 0; i < size; i++) {
		((ItemState) states.get(i)).restore();
	}
}
}