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Virtual tableViewer [message #659006]

Thu, 10 March 2011 16:36

Jan Krakora

Messages: 477
Registered: December 2009
Location: Prague

Senior Member

Hi guys,

I have a question about virtual TableViewers. What's the difference between using just the TableViewer with style SWT.VIRTUAL and using the TableViewer with style SWT.VIRTUAL and the ILazyContentProvider?

I don't understand it. From my point of view is using SWT.VIRTUAL without the ILazyContentProvider useless. Is that true?

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Re: Virtual tableViewer [message #659024 is a reply to message #659006]

Thu, 10 March 2011 17:27

Thomas Schindl

Messages: 6651
Registered: July 2009

Senior Member

No it is not true. If your bottleneck is not the loading of items from
your datasource e.g. because it is a localstorage, you already have the
data in memory, ... SWT.VIRTUAL helps maybe because the SWT-Control does
not have to create all SWT-TableItems at once.

The important difference is also that if you use
ViewerFilter/ViewerComparator they only work with an ordinary content
provider.

Tom

Am 10.03.11 17:36, schrieb Behnil:
> Hi guys,
>
> I have a question about virtual TableViewers. What's the difference
> between using just the TableViewer with style SWT.VIRTUAL and using the
> TableViewer with style SWT.VIRTUAL and the ILazyContentProvider?
>
> I don't understand it. From my point of view is using SWT.VIRTUAL
> without the ILazyContentProvider useless. Is that true?

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Re: Virtual tableViewer [message #659141 is a reply to message #659024]

Fri, 11 March 2011 09:15

Jan Krakora

Messages: 477
Registered: December 2009
Location: Prague

Senior Member

Aaaaa...so:

if I have my whole model in memory, I can still use the SWT.VIRTUAL flag to avoid TableViewer creating all TableItems at once, which speed up creating the table. And I can still use sorting and filtering.

But when is bottleneck loading the model, I need to use ILazyContentProvider, because it can provide one model abject after another when it's needed (scrolling down). But I can't use sorting and filtering.

There is one thing I still don't understand. Why isn't every TableViewer virtual? What are the disadvantages of it?

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