If you call a static method that doesn't access any
external variables that are maintaining state, it will
be safe to call from a thread. Just like the perform
method in your Action class should be thread safe
since it can be used by multiple threads.
The general consensus is that it is good to separate
your business logic from being aware of the web layer.
David
--- Holger Wiechert <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I've got a question about an issue to the thread
> safe execution.
> The whole setup was made in order to have a business
> logic triggered by
> struts, that still can retrieve information from its
> environment -- here Struts -- without
> having explicit knowledge of it. In short, the
> processing is like this:
>
> a) the ActionObject gets the business object
> b) calls the business method on the business object
> including
> -the HttpServletRequest just received in the perform
> call, and
> -a reference to itself
> c) the business object now uses this reference to
> retrieve from this object
> some information about the business objects
> environment. Thus, the business object
> calls the ActionObject (without knowing, that it
> is a struts Action) and hands in
> the HttpServletRequest (as an java.lang.Object).
> d) the ActionObject uses the HttpServletRequest to
> get the desired information
> (like request.getParameter()) and returns the
> result back to the business object.
>
> Basically, I want to know, if I can use a static
> method (no static fields) within the ActionObject
> for performing the environment lookup thread safe.
>
> Sounds a little complicated, doesn't it? Well, to
> those who have the time to get involved.
> It's actually not that difficult.
>
> The class structure in my struts app is like the
> following:
>
> -Class MyActionClass: extends ...struts.Action
> implements myClasses.Environment
>
> -Interface myClasses.Environment has (let's say)
> just one method:
> public boolean isPropertySet(Object helperObject)
>
> -Class DoSomeStuffRq is a class that contains
> a)translated form data, and
> b) an java.lang.Object reference to store the
> HttpServletRequest
> (which the MyActionObject just has recieved in its
> perform method).
>
> -Class MyBusinessClass:
> doSomeBusinessStuff(DoSomeStuffRq stuffInfo,
> Environment env)
>
> The Environment interface is there in order to
> decouple Struts from the business logic - giving
> the chance to reuse the MyBusinessClass when not
> using Struts anymore (well, I hope I don't have to,
> but still).
>
> So finer grained, the actions are:
>
> 1) Let the MyActionClass get the businessObject (of
> type MyBusinessClass),
> 2) MyActionClass calls the method
> businessObject.doSomeBusinessStuff(stuffInfo, this);
>
> ["this" is of type Environment]
>
> 3) in order to process the business actions, the
> BusinessObject has to
> retrieve a boolean value from it's (unknown)
> environment. So it calls
> the isPropertySet from the Environment interface
> (which has the MyActionClass implementation):
>
> public StuffResponse
> doSomeBusinessStuff(DoSomeStuffRq stuffInfo,
> Environment env)
> {
> boolean importantProperty =
>
environment.isPropertySet(stuffInfo.getObjectReference());
> ...
> }
>
> where stuffInfo.getObjectReference() gives the above
> mentioned HttpServletRequest reference as a
> java.lang.Object.
>
> 4) the rest is quite obvious: myActionObject does a
> cast of the java.lang.Object to the
> HttpServletRequest
> and gets a request parameter. Then, it returns a
> boolean value depending on that request parameter.
>
> Well, there's lots to argue about in the whole
> scenario.
> Questions like: does it make sense to do all that
> stuff to decouple business logic and Struts; is
> there
> a better way of passing the parameters between the
> objects, shall the MyActionClass handle the lookup,
> when all I need is a HttpServletRequest and so on.
> But the simple question I'm interested in is: Can I
> have the MyActionClass' method
> public boolean isPropertySet(Object helperObject)
> being static?
>
> I think, I can, because:
> As long as I don't use any class members in the
> MyActionClass, the thread safety shall be
> given -- no matter if the method is static or not.
> Is that true?
> Well it's more a java related question, but I think
> there are some people here, who are interested
> in this issue too.
>
> Thanks in advance for your time,
> Holger
>
>
>
__________________________________________________
Do You Yahoo!?
Get personalized email addresses from Yahoo! Mail
http://personal.mail.yahoo.com/
