/******************************************************************************* * Copyright (c) 2000, 2004 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.swt.widgets;import org.eclipse.swt.*;import org.eclipse.swt.graphics.*;/** * This class is the abstract superclass of all non-windowed * user interface objects that occur within specific controls. * For example, a tree will contain tree items. * <dl> * <dt><b>Styles:</b></dt> * <dd>(none)</dd> * <dt><b>Events:</b></dt> * <dd>(none)</dd> * </dl> */public abstract class Item extends Widget {	String text;	Image image;/** * Constructs a new instance of this class given its parent * and a style value describing its behavior and appearance. * The item is added to the end of the items maintained by its parent. * <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 widget which will be the parent of the new instance (cannot be null) * @param style the style of item 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> * </ul> * * @see SWT * @see #getStyle */public Item (Widget parent, int style) {	super (parent, style);	text = "";}/** * Constructs a new instance of this class given its parent * and a style value describing its behavior and appearance, * and the index at which to place it in the items maintained * by its parent. * <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 widget which will be the parent of the new instance (cannot be null) * @param style the style of item to construct * @param index the index at which to store the receiver in its parent * * @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> * </ul> * * @see SWT * @see #getStyle */public Item (Widget parent, int style, int index) {	this (parent, style);}protected void checkSubclass () {	/* Do Nothing - Subclassing is allowed */}/** * Returns the receiver's image if it has one, or null * if it does not. * * @return the receiver's image * * @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 Image getImage () {	checkWidget ();	return image;}String getNameText () {	return getText ();}/** * Returns the receiver's text, which will be an empty * string if it has never been set. * * @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 text;}void releaseWidget () {	super.releaseWidget ();	text = null;	image = null;}/** * Sets the receiver's image to the argument, which may be * null indicating that no image should be displayed. * * @param image the image to display on the receiver (may be null) * * @exception IllegalArgumentException <ul> *    <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</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 setImage (Image image) {	checkWidget ();	if (image != null && image.isDisposed()) error(SWT.ERROR_INVALID_ARGUMENT);	this.image = image;}/** * Sets the receiver's text. * * @param string the new text * * @exception IllegalArgumentException <ul> *    <li>ERROR_NULL_ARGUMENT - if the text 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);	text = string;}}