Hi Mira:

>From mira@ccs.neu.edu Wed Nov 19 19:43:57 1997
>
>> 
>> Hi Mira:
>> 
>> we can compose adjusters in two ways: by using the modifies
>> relationship between them and by giving several adjusters to the 
>> same strategy. What is the relationship between the two compositions?
>
>In the first case both adjusters are not independent from
>each other: they exist as parts of the same "higher-level"
>modification. The change methods in both adjusters will
>be renamed by the generator with the same name. The super
>parameter in the implementation of the modifier adjuster
>is the corresponding implementation in the modifiee 
>adjuster. For example, when summing is modified
>by initial and the later by checking for realizing
>the capacity checking functionality, all change
>methods will be renamed uniformely to
>check-capacity (or something like that) and they will
>be incremental modifications of each other.
>

Matches my understanding.

>
>On the contrary, in the second case, both adjusters are
>independent from each other. I think, their "changes"

That not match my understanding, see below.

>will be renamed differently. For examle, we could attach
>pricing and inventory to the same strategy on a computer
>object structure. Their corresponding
>changes will be renamed to e.g. equipment-pricing and 
>equipment-inventory respectively.  
>
>> If we give two adjusters as arguments to the same strategy, how can the
>> two adjusters communicate. Cane we add further communication after the
>> adjusters have been written (a la Java beans)?
>> 
>> -- Karl
>
>What do you mean by communication between adjusters? Do you have
>a particular sample scenario in mind?

Let's assume we have a PrintVisitor generated by Demeter/Java
but we want to use it on a circular object. Therefore, we write
an OnlyOnce visitor and write:

A{
  printit() do S (OnlyOnce,PrintVisitor);
}

The OnlyOnce visitor will contain around methods which make sure
that each object is visited  only once. OnlyOnce controls PrintVisitor;
they are not independent.

-- Karl



>
>-- Mira 
>
>