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From David Van Couvering <David.Vancouver...@Sun.COM>
Subject Re: Implementing Statement.cancel()
Date Thu, 02 Jun 2005 16:34:14 GMT
I have had similar difficulties finding navigation paths from one object 
to another within the domain of execution contexts.

I have been toying with the idea of putting together one or two UML 
class diagrams (using an open-source tool, of course :)) to try and show 
the relationships between all these numerous classes and interfaces. 
Every time I get in there I have to re-learn how the pieces fit 
together, and often my internal buffer overflows and I get lost :)

It would also be great to document some of the design 
principles/approaches to this layer of the code, as it's not at all 
clear through reading the code.  I don't have this knowledge, but if 
someone who does can type something up, I can try and put it into a form 
that can be posted as a paper to the web site.

David

Daniel John Debrunner wrote:

> Oyvind.Bakksjo@sun.com wrote:
> 
> 
>>Daniel John Debrunner wrote:
>>
>>
>>>Oyvind.Bakksjo@Sun.COM wrote:
>>>
>>>
>>>
>>>>I've been looking at implementing Statement.cancel(), and later,
>>>>Statement.setQueryTimeout().
>>>
>>>
>>>
>>>So, quick summary, that method is not suitable for finding the correct
>>>StatementContext from EmbedStatement.cancel().
>>>
>>>I'll look into how I think you should track down the StatementContext.
>>>Dan.
>>
>>
>>Hi Dan,
>>
>>have you had any time to look into this?
> 
> Not a lot :-(
> 
> I've been thinking about it and there are a couple of issues:
> 
> 1) StatementContexts are created dynamically for the current running
> statement
> 
> 2) Derby does not keep references to application JDBC objects below the
> JDBC layer. This is to ensure when any JDBC object (e.g. Statement)
> moves out of scope for the application, it will be garbage collected and
> lead to its closure.
> 
> I wonder if from a StatementContext you can determine the activation
> because that would provide the link to the Statement.
> 
> 
> Dan.
> 
> 
> 

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