/*******************************************************************************
 * 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.ui.part;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.Point;

/**
 * A pagebook is a composite control where only a single control is visible
 * at a time. It is similar to a notebook, but without tabs.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 *
 * @see PageBookView
 */
public class PageBook extends Composite {

	/**
	 * <p>
	 * [Issue: This class should be declared private.]
	 * </p>
	 */
	public class PageBookLayout extends Layout {

		protected Point computeSize(
			Composite composite, 
			int wHint, 
			int hHint, 
			boolean flushCache) {
			if (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)
				return new Point(wHint, hHint);

			Point result = null;
			if (currentPage != null) {
				result = currentPage.computeSize(wHint, hHint, flushCache);
			} else {
				//Rectangle rect= composite.getClientArea();
				//result= new Point(rect.width, rect.height);
				result = new Point(0, 0);
			}			
			if (wHint != SWT.DEFAULT)
				result.x = wHint;
			if (hHint != SWT.DEFAULT)
				result.y = hHint;
			return result;
		}

		protected void layout(Composite composite, boolean flushCache) {
			if (currentPage != null) {
				currentPage.setBounds(composite.getClientArea());
			}
		}
	}

	/**
	 * The current control; <code>null</code> if none.
	 */
	private Control currentPage = null;
/**
 * Creates a new empty pagebook.
 *
 * @param parent the parent composite
 * @param style the SWT style bits
 */
public PageBook(Composite parent, int style) {
	super(parent, style);
	setLayout(new PageBookLayout());
}
/**
 * Shows the given page. This method has no effect if the given page is not
 * contained in this pagebook.
 *
 * @param page the page to show
 */
public void showPage(Control page) {

	if (page == currentPage)
		return;
	if (page.getParent() != this)
		return;

	Control oldPage = currentPage;
	currentPage = page;

	// show new page
	if (page != null) {
		if (!page.isDisposed()) {
			page.setVisible(true);
			layout(true);
			//				if (fRequestFocusOnShowPage)
			//					page.setFocus();
		}
	}

	// hide old *after* new page has been made visible in order to avoid flashing
	if (oldPage != null && !oldPage.isDisposed())
		oldPage.setVisible(false);
}
}