/*******************************************************************************

 * Copyright (c) 2000, 2006 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

 *     Nokia Corporation - QT 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 Widget#getStyle

 */

public Item (Widget parent, int style) {

	this (parent, style, 0);

}

/**

 * 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 zero-relative index at which to store the receiver in its parent

 *

 * @exception IllegalArgumentException <ul>

 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>

 *    <li>ERROR_INVALID_RANGE - if the index is not between 0 and the number of elements in the parent (inclusive)</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 Widget#getStyle

 */

public Item (Widget parent, int style, int index) {

	this (parent, style, index, null);

}

/**

 * <p>

 * <b>IMPORTANT:</b> This constructor is <em>not</em> part of the SWT

 * public API. It should never be referenced from application code. 

 * </p>

 */

protected Item(Widget parent, int style, int index, Object packageProxy) {

    super(parent, style, 0, packageProxy, false);

    text = "";

}

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_pp () {

	super.releaseWidget_pp ();

	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;

}

}