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/*******************************************************************************
* 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.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>
*
* @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
*/
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) {
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 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);
}
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;
}
}
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