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/*******************************************************************************
* 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.compare;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.custom.SashForm;
/**
* The Splitter adds support for nesting to a SashForm.
* <P>
* If Splitters are nested directly:
* <UL>
* <LI>changing the visibility of a child may propagate upward to the parent Splitter if the child
* is the last child to become invisible or the first to become visible.</LI>
* <LI>maximizing a child makes it as large as the topmost enclosing Splitter</LI>
* </UL>
*
* @since 2.1
*/
public class Splitter extends SashForm {
private static final String VISIBILITY= "org.eclipse.compare.internal.visibility"; //$NON-NLS-1$
/**
* 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 widget which will be the parent of the new instance (cannot be null)
* @param style the style of widget to construct
*
* @exception IllegalArgumentException <ul>
* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
* </ul>
* @exception org.eclipse.swt.SWTException <ul>
* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
* </ul>
*/
public Splitter(Composite parent, int style) {
super(parent, style);
}
/**
* Sets the visibility of the given child in this Splitter. If this change
* affects the visibility state of the whole Splitter, and if the Splitter
* is directly nested in one or more Splitters, this method recursively
* propagates the new state upward.
*
* @param child the child control for which the visibility is changed
* @param visible the new visibility state
*/
public void setVisible(Control child, boolean visible) {
boolean wasEmpty= isEmpty();
child.setVisible(visible);
child.setData(VISIBILITY, new Boolean(visible));
if (wasEmpty != isEmpty()) {
// recursively walk up
Composite parent= getParent();
if (parent instanceof Splitter) {
Splitter sp= (Splitter) parent;
sp.setVisible(this, visible);
sp.layout();
}
} else {
layout();
}
}
/* (non-Javadoc)
* Recursively calls setMaximizedControl for all direct parents that are
* itself Splitters.
*/
public void setMaximizedControl(Control control) {
if (control == null || control == getMaximizedControl())
super.setMaximizedControl(null);
else
super.setMaximizedControl(control);
// recursively walk upward
Composite parent= getParent();
if (parent instanceof Splitter)
((Splitter) parent).setMaximizedControl(this);
else
layout(true);
}
/* (non-Javadoc)
* Returns true if Splitter has no children or if all children are invisible.
*/
private boolean isEmpty() {
Control[] controls= getChildren();
for (int i= 0; i < controls.length; i++)
if (isVisible(controls[i]))
return false;
return true;
}
/* (non-Javadoc)
* Returns the visibility state of the given child control. If the
* control is a Sash, this method always returns false.
*/
private boolean isVisible(Control child) {
if (child instanceof Sash)
return false;
Object data= child.getData(VISIBILITY);
if (data instanceof Boolean)
return ((Boolean)data).booleanValue();
return true;
}
}
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