Re: [Springframework-developer] JdbcOperationsCallback

[Colin S. <col...@ex...>]

Let's do the ConnectionCallback then. I'll try to add it tomorrow if you 
don't get to it; I'm working on some other code today. As for just 
converting SQL exceptions, I agree that there's no resource management, 
but I'm not so sure the templates are just about resource maangement. 
They're also all about automatic exception translation. I agree though 
that in the case you don't need any resources, it's probably just as 
easy to catch the SQLException yourself, and use a translator, as 
opposed to creating an anonymous class for the callback.. It's just a 
matter of getting at that translator easily. This is easy if yuo have a 
jdbcTemplate. If all you are workig with is the JdbcOperations interface 
it's harder, since it doesn't expose it, so you have to get it in 
separately...

Colin

jürgen höller [werk3AT] wrote:

>We already have a StatementCallback and a PreparedStatementCallback, for example, letting you execute the same Statement object multiple times or whatever you want to do with it. User code is just responsible for closing ResultSets in that case.
> 
>I've considered adding a ConnectionCallback before, passing a managed Connection object in and converting all SQLExceptions. User code would then be responsible for closing Statements and ResultSets accordingly. I wouldn't mind adding such a callback.
> 
>However, a plain callback that just converts SQLExceptions doesn't really fit into JdbcTemplate, because there's no resource managed there. JdbcTemplate wouldn't do anything here; all that's needed is a SQLExceptionTranslator. Therefore, it's probably cleaner to use a try/catch block and delegate to a SQLExceptionTranslator when catching a SQLException. The translator could come from a bean property of type SQLExceptionTranslator, or from getJdbcTemplate().getExceptionTranslator() in a JdbcDaoSupport subclass.
> 
>Juergen
> 
>
>________________________________
>
>Von: spr...@li... im Auftrag von Colin Sampaleanu
>Gesendet: Fr 03.12.2004 14:16
>An: spr...@li...
>Betreff: Re: [Springframework-developer] JdbcOperationsCallback
>
>
>
>Sure, the whole point is that this is not something you are going to use
>given the choice to use other methods on the template, but mainly when
>you need to wrap existing code which throws SQLException. In the
>particular case I needed yesterday, I actually also needed to pass a
>connection to the other code. There could be a variant which gets a
>connection for you, for this sort of case.   I don't like the
>possibility that people will now use this sort of method to write
>old-style code which doesn't clean up resources properly, as you
>mention, but on the other hand, if we document it well it will hopefully
>be helpful for these kinds of situations. In this case, I ended up
>having to manage the connection myself, and had to wrap to catch SQL
>exceptions, etc....
>
>Colin
>
>
>Thomas Risberg wrote:
>
>  
>
>>The only drawback that I can think of is that now you are responsible
>>for closing any statements/resultsets that you open - you need to
>>provide a try/finally block within the callback to properly close them
>>in case of an exception being thrown.  As long as we document this, we
>>should be OK.
>>
>>Thomas
>>
>>Colin Sampaleanu wrote:
>>
>>    
>>
>>>Does anybody think it doesn't make sense to add a
>>>JdbcOperationsCallback interface, similar to some of the other
>>>callbacks, which can be used via a new
>>>  jdbcTemplate.execute(JdbcOperationsCallback)
>>>method? This could be used to wrap arbitrary code which throws SQL
>>>exceptions, so that they are properly mapped. I've had a need for
>>>something like this a few times...
>>>      
>>>
>
>
>
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