From mira@informatik.uni-siegen.de Thu Dec  3 09:31:50 1998
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Subject: Re: Questions
To: ichenp@ccs.neu.edu (I-Chen Pan)
Date: Thu, 3 Dec 1998 15:27:22 +0100 (MET)
From: "Mira Mezini" <mira@informatik.uni-siegen.de>
Cc: mira@informatik.uni-siegen.de, lieber@ccs.neu.edu, bdelav@hotmail.com,
        jayantha@ccs.neu.edu, lorenz@ccs.neu.edu
In-Reply-To: <Pine.GSO.4.05.9812030256160.10121-100000@rigel.ccs.neu.edu> from "I-Chen Pan" at Dec 3, 98 03:12:46 am
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Status: R

> On Wed, 2 Dec 1998, Mira Mezini wrote:
>         ....
> 
> > 1- Complete my code. 
> > 
> > Why? 
> > In order to get e2 events for edges such as e.g., ``before ->D,Z''
> > we cannot simply ignore s1 node events such as ``before G'' (for nodes
> > that are not in s2), as I do. 
> > Indeed, we don't generate output events in this case, but 
> > we need to somehow store nodes in the s1's path from A to D so that we can 
> > generate ``before/after ->A,D'' events for s2. 
> > One way I can think of implementing this, is to have a stack 
> > as the storage medium. E.g., for the input ``before G'' we would simply
> > push G on the stack. Note that also nodes like A that are both in
> > s1 and s2 should be stored in the stack. In a similar way, after 
> > node events we would pop from the corresponding node from the stack.
> 
> Q1 : The algorithm below doesn't seem to work if the traversal strategy is
> like A-> {B C}. The traversal will be 
>         S2
>        before A
>        before -> A, D
>         ....
>        before -> A, C
>     
> I mean, if we just check whether the source matches or not in the stack.
> Or the situation will not happen in a refined strategy. 

Please note that what I have written is only an idea. Don't take it
as the given algorithm. It is a skeleton of what I think the
algorithm would loook like (more or less). I haven't worked out 
details. It was intended to give you an idea of what is required
to do. You can think of a another better algorithm if you want,
or work out the details of this skeleton if you think
that the main idea seems to work.

> 
> Q2 : Just want to make sure that the stack you mentioned
> above in traversalEvent(NodeEvent) and the one below in
>  traversalEvent(EdgeEvent) are the same stack.
> 

Yes it will be the same -- the stack would be a private instance 
variable of in the class APPCBean.

- Mira