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ContentProvider for TableViewer Problem [message #459861]

Thu, 18 August 2005 12:20

Eclipse User

This return in the method within a ContentProvider

public Object[] getElements(Object inputElement) (
return inputElement.getCases().toArray();

needs to be replaced with something not using the parameter inputElement
like
return caseList.getCases().toArray();

because the method gets called before setInput is called causing a null
pointer exception. It would seem that the getElements method should not
be called until setInput is called. Am I missing something?

Re: ContentProvider for TableViewer Problem [message #459920 is a reply to message #459861]

Thu, 18 August 2005 13:09

Eclipse User

Originally posted by: sunil_kamath.nohotspammail.com

"James Leotta" <jleotta@bascom.com> wrote in message
news:de2cds$mhv$1@news.eclipse.org...
> This return in the method within a ContentProvider
>
> public Object[] getElements(Object inputElement) (
> return inputElement.getCases().toArray();
>
>
> needs to be replaced with something not using the parameter inputElement
> like
> return caseList.getCases().toArray();
>
> because the method gets called before setInput is called causing a null
> pointer exception. It would seem that the getElements method should not
> be called until setInput is called. Am I missing something?

Yes you are.
You should check for nulls in the getElements() method.
If inputElement == null, then return null.
---
Sunil

Re: ContentProvider for TableViewer Problem [message #459926 is a reply to message #459861]

Thu, 18 August 2005 17:48

Eclipse User

James Leotta wrote:

> This return in the method within a ContentProvider

> public Object[] getElements(Object inputElement) (
> return inputElement.getCases().toArray();

> needs to be replaced with something not using the parameter inputElement
> like
> return caseList.getCases().toArray();

> because the method gets called before setInput is called causing a null
> pointer exception. It would seem that the getElements method should not
> be called until setInput is called. Am I missing something?

Here is how the ArrayContentProvider does it:

public Object[] getElements(Object inputElement) {
if (inputElement instanceof Object[])
return (Object[]) inputElement;
if (inputElement instanceof Collection)
return ((Collection) inputElement).toArray();
return new Object[0];
}

So effectively you should be adding null checks.

Re: ContentProvider for TableViewer Problem [message #459941 is a reply to message #459861]

Fri, 19 August 2005 15:20

Eclipse User

Thanks folks!

James Leotta wrote:
> This return in the method within a ContentProvider
>
> public Object[] getElements(Object inputElement) (
> return inputElement.getCases().toArray();
>
>
> needs to be replaced with something not using the parameter inputElement
> like
> return caseList.getCases().toArray();
>
> because the method gets called before setInput is called causing a null
> pointer exception. It would seem that the getElements method should not
> be called until setInput is called. Am I missing something?

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