Re: AW: AW: Looking up the Struts Datasource

[Wolfgang Woger]

Craig R. McClanahan wrote:

Philipp Röthl wrote:

That's not really what I would like to do.

public ActionForward
      execute(ActionMapping mapping,
              ActionForm form,
              HttpServletRequest request,
              HttpServletResponse response) throws Exception
{
   SomeBean  myBean = new SomeBean();
}
public class SomeBean()
{
  public SomeBean()
{
   //how do I get the Struts DS here - without passing it as an 
attribute?
}

}

Any hints?

 

Short answer -- you don't.

The Struts data source isn't magical -- it's an object like any other 
object, and in order for a method in some bean to talk to an instance, 
the method needs a reference to that object.  Typically, that means 
you need to pass it in as a method parameter, make it visible through 
some static getter or factory method, or make it visible in some 
global repository that is available to the bean instance.

Using JNDI-based data sources is an example of the third approach.  
Indeed, that is one of the main reasons that using JNDI data sources 
should be preferred to using the one provided by Struts -- your method 
inside SomeBean can ask for the data source whenever it needs to, 
without having to pass it around.  (There are other advantages as 
well, but this is the one most relevant to your concern here.)
So, when ever you neet a datasource, the method in SomeBean will have to 
search it in JNDI. Doesn't this pose a performance penalty?


phi

 

Craig



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