On Tue, Jun 2, 2009 at 12:45 PM, ZeckoN <[email protected]> wrote:
>
> If two copies of the same action is run at the same time parallelly (by ajax,
> iframe, etc.) in the same session, possibly with different parameters, do
> these actions call the same instance of an interceptor's intercept() method?
> If this is the case, how to avoid problems that can arise?
>
> For example,
>
> there is an intercept method like
>
> public String intercept(ActionInvocation actionInvocation) throws Exception
> {
> .....Do some pre work....
> String result = actionInvocation.invoke();
> .....Do some after work....
> return result;
> }
>
> when the first copy of action is run, it does the pre work, then invoke() is
> called, at this time action2 is run so it runs pre work, calls it's invoke()
> then while doing after work, first action returns from invoke() thus
> changing the value of result variable. So the result is now first action's
> result and both actions return to the result from the first action, right?
>
> is defining the intercept method as "synchronized" a solution?
>
> thanks for the help.
String result = actionInvocation.invoke() ;
This is thread-safe, another thread will invoke the intercept method,
but the result string is scoped.
I think you might be misunderstanding how threading works. If your
pre-work and post-work only deal with variables locally scoped within
the method, then I don't think there is a problem. Here is an example
of a problem -
public class MyInterceptor extends whatever {
public String classScopedResultString;
public String intercept(ActionInvocation actionInvocation) throws Exception
{
classScopedResultString = "gettingReadyToInvoke";
classScopedResultString = actionInvocation.invoke();
classScopedResultString = "justGotDoneInvoking";
return classScopedResultString;
}
}
-Wes
--
Wes Wannemacher
Author - Struts 2 In Practice
Includes coverage of Struts 2.1, Spring, JPA, JQuery, Sitemesh and more
http://www.manning.com/wannemacher
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