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Bug 340488

Summary:	[Viewers] CheckboxTreeViewer doesnt support ILazyTreeContentProvider
Product:	[Eclipse Project] Platform	Reporter:	Prashant Deva <prashant.deva>
Component:	UI	Assignee:	Platform UI Triaged <platform-ui-triaged>
Status:	CLOSED DUPLICATE	QA Contact:
Severity:	normal
Priority:	P3	CC:	eclipse.felipe, guido.schnepp, harapeti, loskutov, prakash, remy.suen
Version:	3.6.2
Target Milestone:	---
Hardware:	PC
OS:	Windows 7
Whiteboard:

Description Prashant Deva

2011-03-19 10:41:06 EDT

Build Identifier: M20110210-1200

I have noticed that both in my code and the sample code for ILazyTreeContentProvider in Snippet047VirtualLazyTreeViewer, CheckboxTreeViewer behaves incorrectly when using ILazyTreeContentProvider and SWT.VIRTUAL flag.

Since I am sure the Eclipse team is aware of that I would ask-
1. To document this fact in the CheckboxTreeViewer documentation.
2. Support ILazyTreeContentProvider and SWT.VIRTUAL for CheckboxTreeViewer.



Reproducible: Always

Steps to Reproduce:
1. Open Snippet047VirtualLazyTreeViewer from the SWT samples.
2. Replace new TreeViewer() with new ChecboxTreeViewer().
3. Note that when expanding the tree, only 1 child is shown for each node, instead of 100.

Comment 1 Peter Haraszin

2015-12-06 14:32:07 EST

And what is even worse is that when changing the TreeViewer to CheckboxTreeViewer ([1]) in the sample code [2], it leads to a StackOverflowError. Here's a complete stack trace which shows that updateElement, updateChildCount, etc. methods are called until a StackOverflowError occurs:
http://i.imgur.com/EPBoJeg.png

If you complement the code with setting a custom check state provider for the CheckboxTreeViewer, it solves the problem:

<code>
<pre>
v.setCheckStateProvider(new ICheckStateProvider() {

	/**
	 * TODO: provide complete solution if checkboxes are really needed
	 */
	@Override
	public boolean isGrayed(Object element) {
		return false;
	}

	/**
	 * TODO: provide complete solution if checkboxes are really needed
	 */
	@Override
	public boolean isChecked(Object element) {
		return false;
	}
});
</pre>
</code>

[1]: http://help.eclipse.org/luna/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fjface%2Fviewers%2FCheckboxTreeViewer.html

[2]: https://github.com/vogella/eclipse.platform.ui/blob/master/examples/org.eclipse.jface.snippets/Eclipse%20JFace%20Snippets/org/eclipse/jface/snippets/viewers/Snippet047VirtualLazyTreeViewer.java#L132

Comment 2 Guido Schnepp

2017-07-06 02:26:04 EDT

Just tried this with Eclipse Oxygen 4.7 on 2017-07-06: This problem still exists today. :-( Luckily the solution works for me, too.

Comment 3 Guido Schnepp

2017-07-06 02:37:29 EDT

Duplicate of bug 58848 from 2004. Still open.
https://bugs.eclipse.org/bugs/show_bug.cgi?id=58848

Comment 4 Andrey Loskutov

2017-07-06 02:46:10 EDT

https://wiki.eclipse.org/Platform_UI/How_to_Contribute

*** This bug has been marked as a duplicate of bug 58848 ***