Re: Help in Project Model

From:
Jason Cavett <jason.cavett@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Thu, 29 Nov 2007 07:10:42 -0800 (PST)
Message-ID:
<64c2a1c2-c533-4918-a3c7-23805e4802ed@s12g2000prg.googlegroups.com>
On Nov 28, 5:27 pm, pek <kimwl...@gmail.com> wrote:

On Nov 28, 6:28 am, Jason Cavett <jason.cav...@gmail.com> wrote:

On Nov 27, 12:02 pm, pek <kimwl...@gmail.com> wrote:

Hello everyone and thnx for any help..

I have a little structure problem. I don't quite know how to model my
objects. Any help is appreciated.

So, the problem is this. I have a class named Motherboard. Now, I know
motherboards support modules such as CPU, Memory etc. So I have to
create a spec for each module. Then I want to create some, let's say
for now, CPU Modules that have name, the specs etc. I want to select a
CPU and find out if the motherboard supports this CPU module.

My current model is the following.
I have a class (probably an Interface) ModuleSpec. For each separate
module (CPU, Memory etc.) you implements this and have it's
specifications that a motherboard needs to know (CPU Socket etc.).
Then I have a Module class (also probably an Interface) that each
separate module implements (CPUModule, MemoryModule) etc. And finally
a Motherboard class that has a list of ModuleSpec.


I'm going to stop reading here because I have some questions. First,
for clarification, are you saying:

public class CPUModule implements ModuleSpec, Module

Is that right? If so, why do you have a ModuleSpec AND a Module.
What does that give you? In fact, you kind of say it yourself...

So it's kinda useless to define the same things in both classes.


BTW - I think you mean "both interfaces," but that's a minor point.

The rest gets confusing and, at this point, I don't think it matters.


Yes, I didn't exactly explained it correctly.

No, CPUModule implements Module (which currently does nothing other
than defining it's a Module).
CPUModuleSpec on the other hand implements ModuleSpec (which
implements the method isCompatible(Module module)).

CPUModuleSpec has a list of CPUSockets (to define what type of sockets
it can support)
CPUModule on the other hand has only one CPUSocket.

These two have in common a CPUSocket, but the Spec has it multiple
times and the Module only once.
I just try to figure out what is the best practice for this.

Thank you.


Okay, so the way you currently have it is...

class CPUModule implements Module {
  CPUSocket socket;

  // other stuff done here
}

class CPUModuleSpec implements ModuleSpec {
  List<CPUSocket> sockets;

  public boolean isCompatible(Module module) {
    // implementation to check of module is part of the sockets list
    // return true if the CPUModule can support the socket, false
otherwise
  }
}

Assuming I got all that right from your description...well...

From the looks of things, everything *seems* to be fine (without know
more about your problem, of course). It seems as though CPUModule
should have a CPUModuleSpec (AKA - there is a CPUModuleSpec variable
within CPUModule).

The isCompatible(Module) method makes sense because you want to check
your spec before you set a socket on the CPUModuleSpec by looking at
the list of sockets. SO...I would do something like this...

class CPUModule implements Module {
  CPUModuleSpec specification;
  CPUSocket socket;

  public void setSocket(CPUSocket socket) {
    if(specification.isCompatible(socket)) {
      this.socket = socket;
    }
  }
}

CPUModuleSpec would stay the same. Basically, you want CPUModule to
have its spec so it can use the spec to enforce certain rules. Does
that make sense?

Hope that helps.

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