Java Servelts and Persistent Variables

[Nino Skilj]

I'm not so great with the whole Java thing, but am trying something I
cannot figure out.

I have three servlet classes, DisplayData, DoCalculations, and
SpecialCases.
DisplayData calls DoCalculations.

DoCalculations takes a lot of information from a database, sorts
through it and runs all the business logic to figure out what the best
possible schedules are possible for a given month. Well, in that month
there are special cases (where certain events cannot occur on certain
days for example). In these cases, SpecialCases is called (only where
needed) and refers to about 10 different methods (ex. notAvailSunday,
etc).

Anyways, each special case adjusts anywhere from 2-3 different arrays
of information. This does not allow me to simply return(array[][]).
So, is there a way for SpecialCases to recognize variables defined in
DoCalculations? Something like a grand global variable? What would be
the approach?

Thanks,
Nino Skilj

 

[Dirk Michaelsen]

Hi,

Anyways, each special case adjusts anywhere from 2-3 different arrays
of information. This does not allow me to simply return(array[][]).
So, is there a way for SpecialCases to recognize variables defined in
DoCalculations? Something like a grand global variable? What would be
the approach?

before you forward the request to the SpecialCases servlet add the
object to the request stream:

request.getSession().addAttribute("myarray",the_array);


In the SpecialCases servlet you get the object from the request
stream:

array_type the_array = (array_type)request.getAttribute("myarray");

cu
Dirk

 

[Ryan Stewart]

Hi,

Anyways, each special case adjusts anywhere from 2-3 different arrays
of information. This does not allow me to simply return(array[][]).
So, is there a way for SpecialCases to recognize variables defined in
DoCalculations? Something like a grand global variable? What would be
the approach?

before you forward the request to the SpecialCases servlet add the
object to the request stream:

request.getSession().addAttribute("myarray",the_array);

In the SpecialCases servlet you get the object from the request
stream:

array_type the_array = (array_type)request.getAttribute("myarray");

You can't put something in the session and get it from the request. You also
don't "add" attributes. You want either
request.setAttribute(...);
request.getAttribute(...);

or

request.getSession().setAttribute(...);
request.getSession().getAttribute(...);

 

[Dirk Michaelsen]

Hi Ryan,

you are right, my apologies. What I ment was this:

request.getSession().setAttribute(...);
request.getSession().getAttribute(...);

cu
Dirk