bundles/org.eclipse.swt/Eclipse SWT/cocoa/org/eclipse/swt/widgets/Combo.java

/*******************************************************************************
 * Copyright (c) 2000, 2008 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.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.cocoa.*;

/**
 * Instances of this class are controls that allow the user
 * to choose an item from a list of items, or optionally 
 * enter a new value by typing it into an editable text
 * field. Often, <code>Combo</code>s are used in the same place
 * where a single selection <code>List</code> widget could
 * be used but space is limited. A <code>Combo</code> takes
 * less space than a <code>List</code> widget and shows
 * similar information.
 * <p>
 * Note: Since <code>Combo</code>s can contain both a list
 * and an editable text field, it is possible to confuse methods
 * which access one versus the other (compare for example,
 * <code>clearSelection()</code> and <code>deselectAll()</code>).
 * The API documentation is careful to indicate either "the
 * receiver's list" or the "the receiver's text field" to 
 * distinguish between the two cases.
 * </p><p>
 * Note that although this class is a subclass of <code>Composite</code>,
 * it does not make sense to add children to it, or set a layout on it.
 * </p>
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>DROP_DOWN, READ_ONLY, SIMPLE</dd>
 * <dt><b>Events:</b></dt>
 * <dd>DefaultSelection, Modify, Selection, Verify</dd>
 * </dl>
 * <p>
 * Note: Only one of the styles DROP_DOWN and SIMPLE may be specified.
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see List
 * @see <a href="http://www.eclipse.org/swt/snippets/#combo">Combo 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>
 */
public class Combo extends Composite {
	int textLimit = LIMIT;

	/**
	 * the operating system limit for the number of characters
	 * that the text field in an instance of this class can hold
	 */
	public static final int LIMIT;
	
	/*
	* These values can be different on different platforms.
	* Therefore they are not initialized in the declaration
	* to stop the compiler from inlining.
	*/
	static {
		LIMIT = 0x7FFFFFFF;
	}
	

/**
 * 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#DROP_DOWN
 * @see SWT#READ_ONLY
 * @see SWT#SIMPLE
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public Combo (Composite parent, int style) {
	super (parent, checkStyle (style));
}

/**
 * Adds the argument to the end of the receiver's list.
 *
 * @param string the new item
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the string 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 #add(String,int)
 */
public void add (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	NSString str = NSString.stringWith(string);
	if ((style & SWT.READ_ONLY) != 0) {
		NSMenu nsMenu = ((NSPopUpButton)view).menu();
		NSMenuItem nsItem = (NSMenuItem)new NSMenuItem().alloc();
		nsItem.initWithTitle(str, 0, NSString.stringWith(""));
		nsMenu.addItem(nsItem);
		nsItem.release();
	} else {
		((NSComboBox)view).addItemWithObjectValue(str);
	}
}

/**
 * Adds the argument to the receiver's list at the given
 * zero-relative index.
 * <p>
 * Note: To add an item at the end of the list, use the
 * result of calling <code>getItemCount()</code> as the
 * index or use <code>add(String)</code>.
 * </p>
 *
 * @param string the new item
 * @param index the index for the item
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the string is null</li>
 *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the list (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>
 *
 * @see #add(String)
 */
public void add (String string, int index) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	int count = getItemCount ();
	if (0 > index || index > count) error (SWT.ERROR_INVALID_RANGE);
	NSString str = NSString.stringWith(string);
	if ((style & SWT.READ_ONLY) != 0) {
		NSMenu nsMenu = ((NSPopUpButton)view).menu();
		NSMenuItem nsItem = (NSMenuItem)new NSMenuItem().alloc();
		nsItem.initWithTitle(str, 0, NSString.stringWith(""));
		nsMenu.insertItem(nsItem, index);
		nsItem.release();
	} else {
		((NSComboBox)view).insertItemWithObjectValue(str, index);
	}
}

/**
 * Adds the listener to the collection of listeners who will
 * be notified when the receiver's text is modified, by sending
 * it one of the messages defined in the <code>ModifyListener</code>
 * interface.
 *
 * @param listener the listener which should 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 ModifyListener
 * @see #removeModifyListener
 */
public void addModifyListener (ModifyListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Modify, typedListener);
}

/**
 * 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>
 * <code>widgetSelected</code> is called when the user changes the combo's list selection.
 * <code>widgetDefaultSelected</code> is typically called when ENTER is pressed the combo's text area.
 * </p>
 *
 * @param listener the listener which should 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 #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);
}

/**
 * Adds the listener to the collection of listeners who will
 * be notified when the receiver's text is verified, by sending
 * it one of the messages defined in the <code>VerifyListener</code>
 * interface.
 *
 * @param listener the listener which should 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 VerifyListener
 * @see #removeVerifyListener
 * 
 * @since 3.1
 */
public void addVerifyListener (VerifyListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Verify, typedListener);
}

static int checkStyle (int style) {
	/*
	* Feature in Windows.  It is not possible to create
	* a combo box that has a border using Windows style
	* bits.  All combo boxes draw their own border and
	* do not use the standard Windows border styles.
	* Therefore, no matter what style bits are specified,
	* clear the BORDER bits so that the SWT style will
	* match the Windows widget.
	*
	* The Windows behavior is currently implemented on
	* all platforms.
	*/
	style &= ~SWT.BORDER;

	/*
	* 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.
	*/
	style &= ~(SWT.H_SCROLL | SWT.V_SCROLL);
	style = checkBits (style, SWT.DROP_DOWN, SWT.SIMPLE, 0, 0, 0, 0);
	if ((style & SWT.SIMPLE) != 0) return style & ~SWT.READ_ONLY;
	return style;
}

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

/**
 * Sets the selection in the receiver's text field to an empty
 * selection starting just before the first character. If the
 * text field is editable, this has the effect of placing the
 * i-beam at the start of the text.
 * <p>
 * Note: To clear the selected items in the receiver's list, 
 * use <code>deselectAll()</code>.
 * </p>
 *
 * @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 #deselectAll
 */
public void clearSelection () {
	checkWidget();
	if ((style & SWT.READ_ONLY) == 0) {
		Point selection = getSelection ();
		selection.y = selection.x;
		setSelection (selection);
	}
}

void comboBoxSelectionDidChange(int notification) {
	sendSelection();
}

public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget ();
	int width = 0, height = 0;
	NSControl widget = (NSControl)view;
	NSRect oldRect = widget.frame();
	widget.sizeToFit();
	NSRect newRect = widget.frame();
	widget.setFrame (oldRect);
	width = (int)newRect.width;
	height = (int)newRect.height;
	if (wHint != SWT.DEFAULT) width = wHint;
	if (hHint != SWT.DEFAULT) height = hHint;
	return new Point (width, height);
}

/**
 * Copies the selected text.
 * <p>
 * The current selection is copied to the clipboard.
 * </p>
 *
 * @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 2.1
 */
public void copy () {
	checkWidget ();
	Point selection = getSelection ();
	if (selection.x == selection.y) return;
//	copyToClipboard (getText (selection.x, selection.y));
}

void createHandle () {
	if ((style & SWT.READ_ONLY) != 0) {
		NSPopUpButton widget = (NSPopUpButton)new SWTPopUpButton().alloc();
		widget.initWithFrame(new NSRect(), false);
		widget.menu().setAutoenablesItems(false);
		widget.setTarget(widget);
		widget.setAction(OS.sel_sendSelection);
		widget.setTag(jniRef);
		view = widget;
		parent.view.addSubview_(widget);
	} else {
		NSComboBox widget = (NSComboBox)new SWTComboBox().alloc();
		widget.initWithFrame(new NSRect());
		widget.setTag(jniRef);
		widget.setDelegate(widget);
		view = widget;
		parent.contentView().addSubview_(widget);
	}
}

/**
 * Cuts the selected text.
 * <p>
 * The current selection is first copied to the
 * clipboard and then deleted from the widget.
 * </p>
 *
 * @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 2.1
 */
public void cut () {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) return;
//	Point selection = getSelection ();
//	if (selection.x == selection.y) return;
//	int start = selection.x, end = selection.y;
//	String text = getText ();
//	String leftText = text.substring (0, start);
//	String rightText = text.substring (end, text.length ());
//	String oldText = text.substring (start, end);
//	String newText = "";
//	if (hooks (SWT.Verify) || filters (SWT.Verify)) {
//		newText = verifyText (newText, start, end, null);
//		if (newText == null) return;
//	}
//	char [] buffer = new char [oldText.length ()];
//	oldText.getChars (0, buffer.length, buffer, 0);
//	copyToClipboard (buffer);
//	setText (leftText + newText + rightText, false);
//	start += newText.length ();
//	setSelection (new Point (start, start));
//	sendEvent (SWT.Modify);
}

Color defaultBackground () {
    return display.getSystemColor (SWT.COLOR_LIST_BACKGROUND);
}

Color defaultForeground () {
    return display.getSystemColor (SWT.COLOR_LIST_FOREGROUND);
}

/**
 * Deselects the item at the given zero-relative index in the receiver's 
 * list.  If the item at the index was already deselected, it remains
 * deselected. Indices that are out of range are ignored.
 *
 * @param index the index of the item to deselect
 *
 * @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 deselect (int index) {
	checkWidget ();
	if (index == -1) return;
	if (index == getSelectionIndex ()) {
		if ((style & SWT.READ_ONLY) != 0) {
			((NSPopUpButton)view).selectItem(null);
			sendEvent (SWT.Modify);
		} else {
			((NSComboBox)view).deselectItemAtIndex(index);
		}
	}
}

/**
 * Deselects all selected items in the receiver's list.
 * <p>
 * Note: To clear the selection in the receiver's text field,
 * use <code>clearSelection()</code>.
 * </p>
 *
 * @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 #clearSelection
 */
public void deselectAll () {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) {
		((NSPopUpButton)view).selectItem(null);
		sendEvent (SWT.Modify);
	} else {
		setText ("");
	}
}

int getCharCount() {
	NSString str;
	if ((style & SWT.READ_ONLY) != 0) {
		str = ((NSPopUpButton)view).titleOfSelectedItem();
	} else {
		str = new NSCell(((NSComboBox)view).cell()).title();
	}
	return str.length();
}

/**
 * Returns the item at the given, zero-relative index in the
 * receiver's list. 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 String getItem (int index) {
	checkWidget ();
	int count = getItemCount ();
	if (0 > index || index >= count) error (SWT.ERROR_INVALID_RANGE);
	NSString str;
	if ((style & SWT.READ_ONLY) != 0) {
		str = ((NSPopUpButton)view).itemTitleAtIndex(index);
	} else {
		str = new NSString(((NSComboBox)view).itemObjectValueAtIndex(index));
	}
	if (str == null) error(SWT.ERROR_CANNOT_GET_ITEM);
	char[] buffer = new char[str.length()];
	str.getCharacters_(buffer);
	return new String (buffer);
}

/**
 * Returns the number of items contained in the receiver's list.
 *
 * @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 ();
	if ((style & SWT.READ_ONLY) != 0) {
		return ((NSPopUpButton)view).numberOfItems();
	} else {
		return ((NSComboBox)view).numberOfItems();
	}
}

/**
 * Returns the height of the area which would be used to
 * display <em>one</em> of the items in the receiver's list.
 *
 * @return the height of one 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 getItemHeight () {
	checkWidget ();
	//TODO - not supported by the OS
	return 26;
}

/**
 * Returns a (possibly empty) array of <code>String</code>s which are
 * the items in the receiver's list. 
 * <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's list
 *
 * @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 String [] getItems () {
	checkWidget ();
	int count = getItemCount ();
	String [] result = new String [count];
	for (int i=0; i<count; i++) result [i] = getItem (i);
	return result;
}

int getMininumHeight () {
	return getTextHeight ();
}

/**
 * Returns the orientation of the receiver.
 *
 * @return the orientation style
 * 
 * @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 2.1.2
 */
public int getOrientation () {
	checkWidget();
	return style & (SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT);
}

/**
 * Returns a <code>Point</code> whose x coordinate is the
 * character position representing the start of the selection
 * in the receiver's text field, and whose y coordinate is the
 * character position representing the end of the selection.
 * An "empty" selection is indicated by the x and y coordinates
 * having the same value.
 * <p>
 * Indexing is zero based.  The range of a selection is from
 * 0..N where N is the number of characters in the widget.
 * </p>
 *
 * @return a point representing the selection start and end
 *
 * @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 Point getSelection () {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) {
		return new Point (0, getCharCount ());
	} else {
//		ControlEditTextSelectionRec selection;
//		if (this.selection != null) {
//			selection = this.selection;
//		} else {
//			selection = new ControlEditTextSelectionRec ();
//			OS.GetControlData (handle, (short) OS.kHIComboBoxEditTextPart, OS.kControlEditTextSelectionTag, 4, selection, null);
//		}
//		return new Point (selection.selStart, selection.selEnd);
		return null;
	}
}

/**
 * Returns the zero-relative index of the item which is currently
 * selected in the receiver's list, 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 ();
	if ((style & SWT.READ_ONLY) != 0) {
		return ((NSPopUpButton)view).indexOfSelectedItem();
	} else {
		return ((NSComboBox)view).indexOfSelectedItem();
	}
}

/**
 * Returns a string containing a copy of the contents of the
 * receiver's text field, or an empty string if there are no
 * contents.
 *
 * @return the receiver's text
 *
 * @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 String getText () {
	checkWidget ();
	return getText(0, -1);
}

String getText (int start, int end) {
	NSString str;
	if ((style & SWT.READ_ONLY) != 0) {
		str = ((NSPopUpButton)view).titleOfSelectedItem();
	} else {
		str = new NSCell(((NSComboBox)view).cell()).title();
	}
	if (str == null) return "";
	int length = str.length();
	char[] buffer = new char[length];
	str.getCharacters_(buffer);
	String string = new String(buffer);
	if (end == -1) end = length;
	start = Math.max(0, Math.min(start, length));
	end = Math.max(0, Math.min(end, length));
	return string.substring(start, end);
}

/**
 * Returns the height of the receivers's text field.
 *
 * @return the text height
 *
 * @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 getTextHeight () {
	checkWidget();
	//TODO - not supported by the OS
	return 26;
}

/**
 * Returns the maximum number of characters that the receiver's
 * text field is capable of holding. If this has not been changed
 * by <code>setTextLimit()</code>, it will be the constant
 * <code>Combo.LIMIT</code>.
 * 
 * @return the text limit
 * 
 * @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 #LIMIT
 */
public int getTextLimit () {
	checkWidget();
    return textLimit;
}

/**
 * Gets the number of items that are visible in the drop
 * down portion of the receiver's list.
 * <p>
 * Note: This operation is a hint and is not supported on
 * platforms that do not have this concept.
 * </p>
 *
 * @return the number of items that are visible
 *
 * @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 3.0
 */
public int getVisibleItemCount () {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) {
		return getItemCount ();
	} else {
		return ((NSComboBox)view).numberOfVisibleItems();
	}
}
	
/**
 * 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 string the search item
 * @return the index of the item
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the string 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 (String string) {
	return indexOf (string, 0);
}

/**
 * Searches the receiver's list starting at the given, 
 * zero-relative index until an item is found that is equal
 * to the argument, and returns the index of that item. If
 * no item is found or the starting index is out of range,
 * returns -1.
 *
 * @param string the search item
 * @param start the zero-relative index at which to begin the search
 * @return the index of the item
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the string 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 (String string, int start) {
	checkWidget();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	int count = getItemCount ();
	if (!(0 <= start && start < count)) return -1;
	for (int i=start; i<count; i++) {
		if (string.equals (getItem (i))) {
			return i;
		}
	}
	return -1;
}

/**
 * Pastes text from clipboard.
 * <p>
 * The selected text is deleted from the widget
 * and new text inserted from the clipboard.
 * </p>
 *
 * @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 2.1
 */
public void paste () {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) return;
//	Point selection = getSelection ();
//	int start = selection.x, end = selection.y;
//	String text = getText ();
//	String leftText = text.substring (0, start);
//	String rightText = text.substring (end, text.length ());
//	String newText = getClipboardText ();
//	if (hooks (SWT.Verify) || filters (SWT.Verify)) {
//		newText = verifyText (newText, start, end, null);
//		if (newText == null) return;
//	}
//	if (textLimit != LIMIT) {
//		int charCount = text.length ();
//		if (charCount - (end - start) + newText.length() > textLimit) {
//			newText = newText.substring(0, textLimit - charCount + (end - start));
//		}
//	}
//	setText (leftText + newText + rightText, false);
//	start += newText.length ();
//	setSelection (new Point (start, start));
//	sendEvent (SWT.Modify);
}

/**
 * Removes the item from the receiver's list at the given
 * zero-relative index.
 *
 * @param index the index for the item
 *
 * @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 void remove (int index) {
	checkWidget ();
	if (index == -1) error (SWT.ERROR_INVALID_RANGE);
	int count = getItemCount ();
	if (0 > index || index >= count) error (SWT.ERROR_INVALID_RANGE);
	if ((style & SWT.READ_ONLY) != 0) {
		((NSPopUpButton)view).removeItemAtIndex(index);
	} else {
		((NSComboBox)view).removeItemAtIndex(index);
	}
}

/**
 * Removes the items from the receiver's list which are
 * between the given zero-relative start and end 
 * indices (inclusive).
 *
 * @param start the start of the range
 * @param end the end of the range
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_RANGE - if either the start or end are 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 void remove (int start, int end) {
	checkWidget();
	if (start > end) return;
	int count = getItemCount ();
	if (!(0 <= start && start <= end && end < count)) {
		error (SWT.ERROR_INVALID_RANGE);
	}
	int newEnd = Math.min (end, count - 1);
	for (int i=newEnd; i>=start; i--) {
		remove(i);
	}
}

/**
 * Searches the receiver's list starting at the first item
 * until an item is found that is equal to the argument, 
 * and removes that item from the list.
 *
 * @param string the item to remove
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the string is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the string is not found in the list</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 remove (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	int index = indexOf (string, 0);
	if (index == -1) error (SWT.ERROR_INVALID_ARGUMENT);
	remove (index);
}

/**
 * Removes all of the items from the receiver's list and clear the
 * contents of receiver's text field.
 * <p>
 * @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 removeAll () {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) {
		((NSPopUpButton)view).removeAllItems();
	} else {
		setText ("", true);
		((NSComboBox)view).removeAllItems();
	}
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the receiver's text is modified.
 *
 * @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 ModifyListener
 * @see #addModifyListener
 */
public void removeModifyListener (ModifyListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Modify, listener);
}

/**
 * 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);
}

/**
 * Removes the listener from the collection of listeners who will
 * be notified when the control is verified.
 *
 * @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 VerifyListener
 * @see #addVerifyListener
 * 
 * @since 3.1
 */
public void removeVerifyListener (VerifyListener listener) {
	checkWidget();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Verify, listener);
}

/**
 * Selects the item at the given zero-relative index in the receiver's 
 * list.  If the item at the index was already selected, it remains
 * 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 select (int index) {
	checkWidget ();
	int count = getItemCount ();
	if (0 <= index && index < count) {
		if ((style & SWT.READ_ONLY) != 0) {
			((NSPopUpButton)view).selectItemAtIndex(index);
			sendEvent (SWT.Modify);
		} else {
			((NSComboBox)view).selectItemAtIndex(index);
		}
	}	
}

//boolean sendKeyEvent (int type, Event event) {
//	if (!super.sendKeyEvent (type, event)) {
//		return false;
//	}
//	if (type != SWT.KeyDown) return true;
//	if ((style & SWT.READ_ONLY) != 0) return true;
//	if (event.character == 0) return true;
//	if ((event.stateMask & SWT.COMMAND) != 0) return true;
//	String oldText = "", newText = "";
//	if (hooks (SWT.Verify) || filters (SWT.Verify)) {
//		int charCount = getCharCount ();
//		Point selection = getSelection ();
//		int start = selection.x, end = selection.y;
//		switch (event.character) {
//			case SWT.BS:
//				if (start == end) {
//					if (start == 0) return true;
//					start = Math.max (0, start - 1);
//				}
//				break;
//			case SWT.DEL:
//				if (start == end) {
//					if (start == charCount) return true;
//					end = Math.min (end + 1, charCount);
//				}
//				break;
//			case SWT.CR:
//				return true;
//			default:
//				if (event.character != '\t' && event.character < 0x20) return true;
//				oldText = new String (new char [] {event.character});
//		}
//		newText = verifyText (oldText, start, end, event);
//		if (newText == null) return false;
//		if (charCount - (end - start) + newText.length () > textLimit) {
//			return false;
//		}
//		if (newText != oldText) {
//			String text = getText ();
//			String leftText = text.substring (0, start);
//			String rightText = text.substring (end, text.length ());
//			setText (leftText + newText + rightText, false);
//			start += newText.length ();
//			setSelection (new Point (start, start));
//		}
//	}
//	/*
//	* Post the modify event so that the character will be inserted
//	* into the widget when the modify event is delivered.  Normally,
//	* modify events are sent but it is safe to post the event here
//	* because this method is called from the event loop.
//	*/
//	postEvent (SWT.Modify);
//	return newText == oldText;
//}

void sendSelection () {
	postEvent(SWT.Selection);
}

void setBackground (float [] color) {
	NSColor nsColor;
	if (color == null) {
		return;	// TODO reset to OS default
	} else {
		nsColor = NSColor.colorWithDeviceRed(color[0], color[1], color[2], 1);
	}
	((NSTextField)view).setBackgroundColor(nsColor);
}

void setForeground (float [] color) {
	NSColor nsColor;
	if (color == null) {
		return;	// TODO reset to OS default
	} else {
		nsColor = NSColor.colorWithDeviceRed(color[0], color[1], color[2], 1);
	}
	((NSTextField)view).setTextColor(nsColor);
}

/**
 * Sets the text of the item in the receiver's list at the given
 * zero-relative index to the string argument.
 *
 * @param index the index for the item
 * @param string the new text for the item
 *
 * @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>
 *    <li>ERROR_NULL_ARGUMENT - if the string 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 setItem (int index, String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	int count = getItemCount ();
	if (0 > index || index >= count) error (SWT.ERROR_INVALID_RANGE);
	NSString str = NSString.stringWith(string);
	if ((style & SWT.READ_ONLY) != 0) {
		NSMenuItem nsItem = ((NSPopUpButton)view).itemAtIndex(index);
		nsItem.setTitle(str);
	} else {
		NSComboBox widget = (NSComboBox)view;
		widget.insertItemWithObjectValue(str, index);
		widget.removeItemAtIndex(index + 1);
	}
}

/**
 * Sets the receiver's list to be the given array of items.
 *
 * @param items the array of items
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the items array is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if an item in 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 setItems (String [] items) {
	checkWidget();
	if (items == null) error (SWT.ERROR_NULL_ARGUMENT);
	for (int i=0; i<items.length; i++) {
		if (items [i] == null) error (SWT.ERROR_INVALID_ARGUMENT);
	}
	removeAll();
	if (items.length == 0) return;
	for (int i= 0; i < items.length; i++) {
		NSString str = NSString.stringWith(items[i]);
		if ((style & SWT.READ_ONLY) != 0) {
			NSMenu nsMenu = ((NSPopUpButton)view).menu();
			NSMenuItem nsItem = (NSMenuItem)new NSMenuItem().alloc();
			nsItem.initWithTitle(str, 0, NSString.stringWith(""));
			nsMenu.addItem(nsItem);
			nsItem.release();
		} else {
			((NSComboBox)view).addItemWithObjectValue(str);
		}
	}
}

/**
 * Marks the receiver's list as visible if the argument is <code>true</code>,
 * and marks it invisible otherwise.
 * <p>
 * If one of the receiver's ancestors is not visible or some
 * other condition makes the receiver not visible, marking
 * it visible may not actually cause it to be displayed.
 * </p>
 *
 * @param visible the new visibility state
 *
 * @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*/ void setListVisible (boolean visible) {
	checkWidget ();
	if ((style & SWT.READ_ONLY) != 0) {
		((NSPopUpButton)view).setPullsDown(visible);
	} else {
	}
}

/**
 * Sets the orientation of the receiver, which must be one
 * of the constants <code>SWT.LEFT_TO_RIGHT</code> or <code>SWT.RIGHT_TO_LEFT</code>.
 * <p>
 *
 * @param orientation new orientation style
 * 
 * @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 2.1.2
 */
public void setOrientation (int orientation) {
	checkWidget();
}

/**
 * Sets the selection in the receiver's text field to the
 * range specified by the argument whose x coordinate is the
 * start of the selection and whose y coordinate is the end
 * of the selection. 
 *
 * @param selection a point representing the new selection start and end
 *
 * @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>
 */
public void setSelection (Point selection) {
	checkWidget ();
	if (selection == null) error (SWT.ERROR_NULL_ARGUMENT);
	if ((style & SWT.READ_ONLY) == 0) {
//		int length = getCharCount ();
//		int start = selection.x, end = selection.y;
//		ControlEditTextSelectionRec sel = new ControlEditTextSelectionRec ();
//		sel.selStart = (short) Math.min (Math.max (Math.min (start, end), 0), length);
//		sel.selEnd = (short) Math.min (Math.max (Math.max (start, end), 0), length);
//		if (hasFocus ()) {
//			OS.SetControlData (handle, OS.kHIComboBoxEditTextPart, OS.kControlEditTextSelectionTag, 4, sel);
//		} else {
//			this.selection = sel;
//		}
	}
}

/**
 * Sets the contents of the receiver's text field to the
 * given string.
 * <p>
 * Note: The text field in a <code>Combo</code> is typically
 * only capable of displaying a single line of text. Thus,
 * setting the text to a string containing line breaks or
 * other special characters will probably cause it to 
 * display incorrectly.
 * </p>
 *
 * @param string the new text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the string 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 setText (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	setText (string, true);
}

void setText (String string, boolean notify) {
	if (notify) {
		if (hooks (SWT.Verify) || filters (SWT.Verify)) {
			string = verifyText (string, 0, getCharCount (), null);
			if (string == null) return;
		}
	}
	if ((style & SWT.READ_ONLY) != 0) {
		int index = indexOf (string);
		if (index != -1 && index != getSelectionIndex ()) {
			select (index);
			if (notify) sendEvent (SWT.Modify);
		}
	} else {
		new NSCell(((NSComboBox)view).cell()).setTitle(NSString.stringWith(string));
		if (notify) sendEvent (SWT.Modify);
	}
}

/**
 * Sets the maximum number of characters that the receiver's
 * text field is capable of holding to be the argument.
 * <p>
 * To reset this value to the default, use <code>setTextLimit(Combo.LIMIT)</code>.
 * Specifying a limit value larger than <code>Combo.LIMIT</code> sets the
 * receiver's limit to <code>Combo.LIMIT</code>.
 * </p>
 * @param limit new text limit
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_CANNOT_BE_ZERO - if the limit is zero</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 #LIMIT
 */
public void setTextLimit (int limit) {
	checkWidget ();
	if (limit == 0) error (SWT.ERROR_CANNOT_BE_ZERO);
	textLimit = limit;
}

/**
 * Sets the number of items that are visible in the drop
 * down portion of the receiver's list.
 * <p>
 * Note: This operation is a hint and is not supported on
 * platforms that do not have this concept.
 * </p>
 *
 * @param count the new number of items to be visible
 *
 * @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 3.0
 */
public void setVisibleItemCount (int count) {
	checkWidget ();
	if (count < 0) return;
	if ((style & SWT.READ_ONLY) != 0) {
		//TODO 
	} else {
		((NSComboBox)view).setNumberOfVisibleItems(count);
	}
}

String verifyText (String string, int start, int end, Event keyEvent) {
	Event event = new Event ();
	event.text = string;
	event.start = start;
	event.end = end;
	if (keyEvent != null) {
		event.character = keyEvent.character;
		event.keyCode = keyEvent.keyCode;
		event.stateMask = keyEvent.stateMask;
	}
	/*
	 * It is possible (but unlikely), that application
	 * code could have disposed the widget in the verify
	 * event.  If this happens, answer null to cancel
	 * the operation.
	 */
	sendEvent (SWT.Verify, event);
	if (!event.doit || isDisposed ()) return null;
	return event.text;
}

}