Re: [Springframework-developer] Question about need for DAo's or Business Objects to keep a session factory refrence

[Cameron B. <ca...@da...>]

Thanks for y our prompt reply.

Yeah, that all makes sense.

In regards to mapping for an abstract class - is it possible to specify 
a mapping that gets inherited automatically, based on the class hierarchy

i.e. Map the HibernateDaoSupport.sessionFactory property to name 
"mySessionFactory", and then any class that extends HibernateDaoSupport 
inherit that mapping ?

Thanks again.

Cameron.

Colin Sampaleanu wrote:

> Cameron Braid wrote:
>
>> I am just beginning to use the Spring framework, and so far I am very 
>> impressed.
>>
>> One thing that I don't quite understand is the mandatory requirement 
>> for each DAO and BO (Business Object) to support the 
>> set/getSessionFactory method.
>>
>> The reason that I say it is mandatory is because the only way to 
>> obtain the current session (as far as I know) is to use 
>> SessionFactoryUtils.getSession(SessionFactory...).  This means that 
>> each DAO/BO requires a setSessionFactory property to be able to be 
>> passed it from the spring container.  This also requires that each 
>> DAO/BO to be configured to bind the SessionFactory instance within 
>> the applicationContext.xml
>>
>> What I would think would be a simple and quite common use case would 
>> be for an app to require only one session factory. Therefore I think 
>> that the SessionFactoryUtils, and related classes , could use a 
>> static field to store the 'default' session factory.
>>
>> Has something like this been considered ?
>> Do you think that this is a good or a bad idea ?
>>
> Cameron,
>
> To clarify, your business objects would generally do not need to have 
> a setSessionFactory method. They would need setters for one or more 
> Mapper/DAO objects, and those Mapper/DAO objects would need the 
> setSessionFactory method.
>
> As for the idea of having the Mapper/DAO objects not need the session 
> factory parameter, and getting it from a singleton of some sort, that 
> approach would work for some use cases, but using a singleton like 
> this is just not very clean. It becomes harder to test code in 
> isolation, and usually locks you into the singleton approach.
>
> You are at most going to declare each mapper/dao once in the 
> application context. Giving it the session factory paramter is not a 
> big deal. In terms of the actual code in the mapper/dao to support 
> this, this can be provided by an abstract base class, and in fact 
> Spring has such a class (for Hibernate) called HibernateDaoSupport.
>
> Regards,
> Colin
>
>
>
>
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