/*******************************************************************************
 * Copyright (c) 2000, 2012 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;


import org.eclipse.swt.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.gtk.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.events.*;

/**
 * Instances of this class implement the notebook user interface
 * metaphor.  It allows the user to select a notebook page from
 * set of pages.
 * <p>
 * The item children that may be added to instances of this class
 * must be of type <code>TabItem</code>.
 * <code>Control</code> children are created and then set into a
 * tab item using <code>TabItem#setControl</code>.
 * </p><p>
 * Note that although this class is a subclass of <code>Composite</code>,
 * it does not make sense to set a layout on it.
 * </p><p>
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>TOP, BOTTOM</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Selection</dd>
 * </dl>
 * <p>
 * Note: Only one of the styles TOP and BOTTOM may be specified.
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/snippets/#tabfolder">TabFolder, TabItem snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * @noextend This class is not intended to be subclassed by clients.
 */
public class TabFolder extends Composite {
	TabItem [] items;
	ImageList imageList;

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a composite control which will be the parent of the new instance (cannot be null)
 * @param style the style of control to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 *
 * @see SWT
 * @see SWT#TOP
 * @see SWT#BOTTOM
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public TabFolder (Composite parent, int style) {
	super (parent, checkStyle (style));
}

static int checkStyle (int style) {
	style = checkBits (style, SWT.TOP, SWT.BOTTOM, 0, 0, 0, 0);
	/*
	* Even though it is legal to create this widget
	* with scroll bars, they serve no useful purpose
	* because they do not automatically scroll the
	* widget's client area.  The fix is to clear
	* the SWT style.
	*/
	return style & ~(SWT.H_SCROLL | SWT.V_SCROLL);
}

@Override
protected void checkSubclass () {
	if (!isValidSubclass ()) error (SWT.ERROR_INVALID_SUBCLASS);
}

@Override
long /*int*/ childStyle () {
	long /*int*/ rcStyle = OS.gtk_widget_get_modifier_style (handle);
	if ((OS.gtk_rc_style_get_color_flags (rcStyle, 0) & OS.GTK_RC_BG) != 0) return 0;
	OS.gtk_widget_realize (handle);
	return OS.gtk_widget_get_style (handle);
}

/**
 * Adds the listener to the collection of listeners who will
 * be notified when the user changes the receiver's selection, by sending
 * it one of the messages defined in the <code>SelectionListener</code>
 * interface.
 * <p>
 * When <code>widgetSelected</code> is called, the item field of the event object is valid.
 * <code>widgetDefaultSelected</code> is not called.
 * </p>
 *
 * @param listener the listener which should be notified when the user changes the receiver's selection
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #removeSelectionListener
 * @see SelectionEvent
 */
public void addSelectionListener(SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener(listener);
	addListener(SWT.Selection,typedListener);
	addListener(SWT.DefaultSelection,typedListener);
}

@Override
long /*int*/ clientHandle () {
	int index = OS.gtk_notebook_get_current_page (handle);
	if (index != -1 && items [index] != null) {
		return items [index].pageHandle;
	}
	return handle;
}

@Override
public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget ();
	Point size = super.computeSize (wHint, hHint, changed);
	if (wHint != SWT.DEFAULT && wHint < 0) wHint = 0;
	if (hHint != SWT.DEFAULT && hHint < 0) hHint = 0;
	boolean scrollable = OS.gtk_notebook_get_scrollable (handle);
	OS.gtk_notebook_set_scrollable (handle, false);
	Point notebookSize = computeNativeSize (handle, wHint, hHint, changed);
	OS.gtk_notebook_set_scrollable (handle, scrollable);
	if (OS.GTK_VERSION >= OS.VERSION (3, 2, 0)) {
		int[] initialGap = new int[1];
		OS.gtk_widget_style_get (handle, OS.initial_gap, initialGap, 0);
		notebookSize.x += initialGap[0]*2;
	}
	size.x = Math.max (notebookSize.x, size.x);
	size.y = Math.max (notebookSize.y, size.y);
	return size;
}

@Override
public Rectangle computeTrim (int x, int y, int width, int height) {
	checkWidget();
	forceResize ();
	long /*int*/ clientHandle = clientHandle ();
	GtkAllocation allocation = new GtkAllocation ();
	gtk_widget_get_allocation (clientHandle, allocation);
	int clientX = allocation.x;
	int clientY = allocation.y;
	x -= clientX;
	y -= clientY;
	width +=  clientX + clientX;
	if ((style & SWT.BOTTOM) != 0) {
		int clientHeight = allocation.height;
		gtk_widget_get_allocation (handle, allocation);
		int parentHeight = allocation.height;
		height += parentHeight - clientHeight;
	} else {
		height +=  clientX + clientY;
	}
	return new Rectangle (x, y, width, height);
}

@Override
void createHandle (int index) {
	state |= HANDLE;
	fixedHandle = OS.g_object_new (display.gtk_fixed_get_type (), 0);
	if (fixedHandle == 0) error (SWT.ERROR_NO_HANDLES);
	gtk_widget_set_has_window (fixedHandle, true);
	handle = OS.gtk_notebook_new ();
	if (handle == 0) error (SWT.ERROR_NO_HANDLES);
	OS.gtk_container_add (fixedHandle, handle);
	OS.gtk_notebook_set_show_tabs (handle, true);
	OS.gtk_notebook_set_scrollable (handle, true);
	if ((style & SWT.BOTTOM) != 0) {
		OS.gtk_notebook_set_tab_pos (handle, OS.GTK_POS_BOTTOM);
	}
}

@Override
void createWidget (int index) {
	super.createWidget(index);
	items = new TabItem [4];
}

void createItem (TabItem item, int index) {
	long /*int*/ list = OS.gtk_container_get_children (handle);
	int itemCount = 0;
	if (list != 0) {
		itemCount = OS.g_list_length (list);
		OS.g_list_free (list);
	}
	if (!(0 <= index && index <= itemCount)) error (SWT.ERROR_INVALID_RANGE);
	if (itemCount == items.length) {
		TabItem [] newItems = new TabItem [items.length + 4];
		System.arraycopy (items, 0, newItems, 0, items.length);
		items = newItems;
	}
	long /*int*/ boxHandle = gtk_box_new (OS.GTK_ORIENTATION_HORIZONTAL, false, 0);
	if (boxHandle == 0) error (SWT.ERROR_NO_HANDLES);
	long /*int*/ labelHandle = OS.gtk_label_new_with_mnemonic (null);
	if (labelHandle == 0) error (SWT.ERROR_NO_HANDLES);
	long /*int*/ imageHandle = OS.gtk_image_new ();
	if (imageHandle == 0) error (SWT.ERROR_NO_HANDLES);
	OS.gtk_container_add (boxHandle, imageHandle);
	OS.gtk_container_add (boxHandle, labelHandle);
	long /*int*/ pageHandle = OS.g_object_new (display.gtk_fixed_get_type (), 0);
	if (pageHandle == 0) error (SWT.ERROR_NO_HANDLES);
	if (OS.GTK3) {
		OS.gtk_widget_override_background_color (pageHandle, OS.GTK_STATE_FLAG_NORMAL, new GdkRGBA ());
		long /*int*/ region = OS.gdk_region_new ();
		OS.gtk_widget_input_shape_combine_region (pageHandle, region);
		OS.gdk_region_destroy (region);
	}
	OS.g_signal_handlers_block_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
	OS.gtk_notebook_insert_page (handle, pageHandle, boxHandle, index);
	OS.g_signal_handlers_unblock_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
	OS.gtk_widget_show (boxHandle);
	OS.gtk_widget_show (labelHandle);
	OS.gtk_widget_show (pageHandle);
	item.state |= HANDLE;
	item.handle = boxHandle;
	item.labelHandle = labelHandle;
	item.imageHandle = imageHandle;
	item.pageHandle = pageHandle;
	System.arraycopy (items, index, items, index + 1, itemCount++ - index);
	items [index] = item;
	if ((state & FOREGROUND) != 0) {
		item.setForegroundColor (getForegroundColor());
	}
	if ((state & FONT) != 0) {
		item.setFontDescription (getFontDescription());
	}
	if (itemCount == 1) {
		OS.g_signal_handlers_block_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
		OS.gtk_notebook_set_current_page (handle, 0);
		OS.g_signal_handlers_unblock_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
		Event event = new Event();
		event.item = items[0];
		sendSelectionEvent (SWT.Selection, event, false);
		// the widget could be destroyed at this point
	}
}

void destroyItem (TabItem item) {
	int index = 0;
	int itemCount = getItemCount();
	while (index < itemCount) {
		if (items [index] == item) break;
		index++;
	}
	if (index == itemCount) error (SWT.ERROR_ITEM_NOT_REMOVED);
	int oldIndex = OS.gtk_notebook_get_current_page (handle);
	OS.g_signal_handlers_block_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
	OS.gtk_notebook_remove_page (handle, index);
	OS.g_signal_handlers_unblock_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
	System.arraycopy (items, index + 1, items, index, --itemCount - index);
	items [itemCount] = null;
	if (index == oldIndex) {
		int newIndex = OS.gtk_notebook_get_current_page (handle);
		if (newIndex != -1) {
			Control control = items [newIndex].getControl ();
			if (control != null && !control.isDisposed ()) {
				control.setBounds (getClientArea());
				control.setVisible (true);
			}
			Event event = new Event ();
			event.item = items [newIndex];
			sendSelectionEvent (SWT.Selection, event, true);	
			// the widget could be destroyed at this point
		}
	}
}

@Override
long /*int*/ eventHandle () {
	return handle;
}
		
/**
 * Returns the item at the given, zero-relative index in the
 * receiver. Throws an exception if the index is out of range.
 *
 * @param index the index of the item to return
 * @return the item at the given index
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list minus 1 (inclusive)</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public TabItem getItem (int index) {
	checkWidget();
	if (!(0 <= index && index < getItemCount())) error (SWT.ERROR_INVALID_RANGE);	
	long /*int*/ list = OS.gtk_container_get_children (handle);
	if (list == 0) error (SWT.ERROR_CANNOT_GET_ITEM);
	int itemCount = OS.g_list_length (list);
	OS.g_list_free (list);
	if (!(0 <= index && index < itemCount)) error (SWT.ERROR_CANNOT_GET_ITEM);
	return items [index];
}

/**
 * Returns the tab item at the given point in the receiver
 * or null if no such item exists. The point is in the
 * coordinate system of the receiver.
 *
 * @param point the point used to locate the item
 * @return the tab item at the given point, or null if the point is not in a tab item
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the point is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @since 3.4
 */
public TabItem getItem(Point point) {
	checkWidget();
	if (point == null) error (SWT.ERROR_NULL_ARGUMENT);
	long /*int*/ list = OS.gtk_container_get_children (handle);
	if (list == 0) return null;
	int itemCount = OS.g_list_length (list);
	OS.g_list_free (list);
	for (int i = 0; i < itemCount; i++) {
		TabItem item = items[i];
		Rectangle rect = item.getBounds();
		if (rect.contains(point)) return item;
	}
	return null;
}

/**
 * Returns the number of items contained in the receiver.
 *
 * @return the number of items
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getItemCount () {
	checkWidget();
	long /*int*/ list = OS.gtk_container_get_children (handle);
	if (list == 0) return 0;
	int itemCount = OS.g_list_length (list);
	OS.g_list_free (list);
	return itemCount;
}

/**
 * Returns an array of <code>TabItem</code>s which are the items
 * in the receiver. 
 * <p>
 * Note: This is not the actual structure used by the receiver
 * to maintain its list of items, so modifying the array will
 * not affect the receiver. 
 * </p>
 *
 * @return the items in the receiver
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public TabItem [] getItems () {
	checkWidget();
	int count = getItemCount ();
	TabItem [] result = new TabItem [count];
	System.arraycopy (items, 0, result, 0, count);
	return result;
}

/**
 * Returns an array of <code>TabItem</code>s that are currently
 * selected in the receiver. An empty array indicates that no
 * items are selected.
 * <p>
 * Note: This is not the actual structure used by the receiver
 * to maintain its selection, so modifying the array will
 * not affect the receiver. 
 * </p>
 * @return an array representing the selection
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public TabItem [] getSelection () {
	checkWidget();
	int index = OS.gtk_notebook_get_current_page (handle);
	if (index == -1) return new TabItem [0];
	return new TabItem [] {items [index]};
}

/**
 * Returns the zero-relative index of the item which is currently
 * selected in the receiver, or -1 if no item is selected.
 *
 * @return the index of the selected item
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int getSelectionIndex () {
	checkWidget();
	return OS.gtk_notebook_get_current_page (handle);
}

@Override
long /*int*/ gtk_focus (long /*int*/ widget, long /*int*/ directionType) {
	return 0;
}

@Override
long /*int*/ gtk_switch_page (long /*int*/ widget, long /*int*/ page, long /*int*/ page_num) {
	int index = OS.gtk_notebook_get_current_page (handle);
	if (index != -1) {
		Control control = items [index].getControl ();
		if (control != null && !control.isDisposed ()) {
			control.setVisible (false);
		}
	}
	TabItem item = items [(int)/*64*/page_num];
	Control control = item.getControl ();
	if (control != null && !control.isDisposed ()) {
		control.setBounds(getClientArea());
		control.setVisible (true);
	}
	Event event = new Event();
	event.item = item;
	sendSelectionEvent (SWT.Selection, event, false);
	return 0;
}

@Override
void hookEvents () {
	super.hookEvents ();
	OS.g_signal_connect_closure (handle, OS.switch_page, display.getClosure (SWITCH_PAGE), false);
}

/**
 * Searches the receiver's list starting at the first item
 * (index 0) until an item is found that is equal to the 
 * argument, and returns the index of that item. If no item
 * is found, returns -1.
 *
 * @param item the search item
 * @return the index of the item
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the item is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public int indexOf (TabItem item) {
	checkWidget();
	if (item == null) error (SWT.ERROR_NULL_ARGUMENT);
	long /*int*/ list = OS.gtk_container_get_children (handle);
	if (list == 0) return -1;
	int count = OS.g_list_length (list);
	OS.g_list_free (list);
	for (int i=0; i<count; i++) {
		if (items [i] == item) return i;
	}
	return -1;
}

@Override
Point minimumSize (int wHint, int hHint, boolean flushCache) {
	Control [] children = _getChildren ();
	int width = 0, height = 0;
	for (int i=0; i<children.length; i++) {
		Control child = children [i];
		int index = 0;
		int count = 0;
		long /*int*/ list = OS.gtk_container_get_children (handle);
		if (list != 0) {
			count = OS.g_list_length (list);
			OS.g_list_free (list);
		}
		while (index < count) {
			if (items [index].control == child) break;
			index++;
		}
		if (index == count) {
			Rectangle rect = child.getBounds ();
			width = Math.max (width, rect.x + rect.width);
			height = Math.max (height, rect.y + rect.height);
		} else {
			Point size = child.computeSize (wHint, hHint, flushCache);
			width = Math.max (width, size.x);
			height = Math.max (height, size.y);
		}
	}
	return new Point (width, height);
}

@Override
boolean mnemonicHit (char key) {
	int itemCount = getItemCount ();
	for (int i=0; i<itemCount; i++) {
		long /*int*/ labelHandle = items [i].labelHandle;
		if (labelHandle != 0 && mnemonicHit (labelHandle, key)) return true;
	}
	return false;
}

@Override
boolean mnemonicMatch (char key) {
	int itemCount = getItemCount ();
	for (int i=0; i<itemCount; i++) {
		long /*int*/ labelHandle = items [i].labelHandle;
		if (labelHandle != 0 && mnemonicHit (labelHandle, key)) return true;
	}
	return false;
}

@Override
void releaseChildren (boolean destroy) {
	if (items != null) {
		for (int i=0; i<items.length; i++) {
			TabItem item = items [i];
			if (item != null && !item.isDisposed ()) {
				item.release (false);
			}
		}
		items = null;
	}
	super.releaseChildren (destroy);
}

@Override
void releaseWidget () {
	super.releaseWidget ();
	if (imageList != null) imageList.dispose ();
	imageList = null;
}

@Override
void removeControl (Control control) {
	super.removeControl (control);
	int count = getItemCount ();
	for (int i=0; i<count; i++) {
		TabItem item = items [i];
		if (item.control == control) item.setControl (null);
	}
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the user changes the receiver's selection.
 *
 * @param listener the listener which should no longer be notified
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener (SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Selection, listener);
	eventTable.unhook (SWT.DefaultSelection,listener);	
}

@Override
void reskinChildren (int flags) {
	if (items != null) {
		long /*int*/ list = OS.gtk_container_get_children (handle);
		if (list != 0){
			int count = OS.g_list_length (list);
			OS.g_list_free (list);
			for (int i=0; i<count; i++) {
				TabItem item = items [i];
				if (item != null) item.reskin (flags);
			}
		}
	}
	super.reskinChildren (flags);
}

@Override
int setBounds (int x, int y, int width, int height, boolean move, boolean resize) {
	int result = super.setBounds (x, y, width, height, move, resize);
	if ((result & RESIZED) != 0) {
		int index = getSelectionIndex ();
		if (index != -1) {
			TabItem item = items [index];
			Control control = item.control;
			if (control != null && !control.isDisposed ()) {
				control.setBounds (getClientArea ());
			}
		}
	}
	return result;
}

@Override
void setFontDescription (long /*int*/ font) {
	super.setFontDescription (font);
	TabItem [] items = getItems ();
	for (int i = 0; i < items.length; i++) {
		if (items[i] != null) {
			items[i].setFontDescription (font);
		}
	}
}

@Override
void setForegroundColor (GdkColor color) {
	super.setForegroundColor (color);
	TabItem [] items = getItems ();
	for (int i = 0; i < items.length; i++) {
		if (items[i] != null) {
			items[i].setForegroundColor (color);
		}
	}
}

@Override
void setOrientation (boolean create) {
	super.setOrientation (create);
	if (items != null) {
		for (int i=0; i<items.length; i++) {
			if (items[i] != null) items[i].setOrientation (create);
		}
	}
}

/**
 * Selects the item at the given zero-relative index in the receiver. 
 * If the item at the index was already selected, it remains selected.
 * The current selection is first cleared, then the new items are
 * selected. Indices that are out of range are ignored.
 *
 * @param index the index of the item to select
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (int index) {
	checkWidget ();
	if (!(0 <= index && index < getItemCount ())) return;
	setSelection (index, false);
}

void setSelection (int index, boolean notify) {
	if (index < 0) return;
	int oldIndex = OS.gtk_notebook_get_current_page (handle);
	if (oldIndex == index) return;
	if (oldIndex != -1) {
		TabItem item = items [oldIndex];
		Control control = item.control;
		if (control != null && !control.isDisposed ()) {
			control.setVisible (false);
		}
	}
	OS.g_signal_handlers_block_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
	OS.gtk_notebook_set_current_page (handle, index);
	OS.g_signal_handlers_unblock_matched (handle, OS.G_SIGNAL_MATCH_DATA, 0, 0, 0, 0, SWITCH_PAGE);
	int newIndex = OS.gtk_notebook_get_current_page (handle);
	if (newIndex != -1) {
		TabItem item = items [newIndex];
		Control control = item.control;
		if (control != null && !control.isDisposed ()) {
			control.setBounds (getClientArea ());
			control.setVisible (true);
		}
		if (notify) {
			Event event = new Event ();
			event.item = item;
			sendSelectionEvent (SWT.Selection, event, true);
		}
	}
}

/**
 * Sets the receiver's selection to the given item.
 * The current selected is first cleared, then the new item is
 * selected.
 *
 * @param item the item to select
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the item is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @since 3.2
 */
public void setSelection (TabItem item) {
	if (item == null) error (SWT.ERROR_NULL_ARGUMENT);
	setSelection (new TabItem [] {item});
}

/**
 * Sets the receiver's selection to be the given array of items.
 * The current selected is first cleared, then the new items are
 * selected.
 *
 * @param items the array of items
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the items array is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (TabItem [] items) {
	checkWidget();
	if (items == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (items.length == 0) {
		setSelection (-1, false);
	} else {
		for (int i=items.length-1; i>=0; --i) {
			int index = indexOf (items [i]);
			if (index != -1) setSelection (index, false);
		}
	}
}

@Override
boolean traversePage (final boolean next) {
	if (next) {
		OS.gtk_notebook_next_page (handle);
	} else {
		OS.gtk_notebook_prev_page (handle);
	}
	return true;
}

}