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From Berin Loritsch <blorit...@apache.org>
Subject Re: compose() method and developing with avalon pdf
Date Tue, 13 Nov 2001 18:34:17 GMT
Vincent Massol wrote:

> Actually, there is another example in the pdf book :
> 
> if (initialized || disposed) {
>   throw new IllegalStateException ("Illegal call");
> }
> if (null == this.manager) {
>   this.manager = cmanager;
> }
> 
> Is it the recommended way or do you usually assume that the lifecycle is
> enforced ? I have a feeling that you'll answer the following : it depends.
> If you're using excalibur component manager then you don't need these checks
> but if you're not using any component manager, you'd rather check. maybe not
> ... let's see ... :)
> 
> In any case, I'd like to have your opinion.


Bottom line is this:

You should ALWAYS explicitly enforce your contracts.  This leads to secure
components that cannot be interacted with in ways you had no intention of
allowing.


> 
> -Vincent
> 
> ----- Original Message -----
> From: "Vincent Massol" <vmassol@octo.com>
> To: <avalon-dev@jakarta.apache.org>
> Sent: Tuesday, November 13, 2001 6:14 PM
> Subject: compose() method and developing with avalon pdf
> 
> 
> 
>>Hi,
>>
>>In the developing with avalon pdf, there is an example of how to implement
>>the compose() method :
>>
>>public void compose(ComponentManager manager) throws ComponentException {
>>  if (this.manager == null) {
>>    this.manager = manager;
>>    myGuard = (Guardian) this.manager.lookup(Guardian.ROLE);
>>  }
>>}
>>
>>I'm wondering why there is a test to verify if the manager is not null
>>
> (i.e.
> 
>>to verify if the compose() method has not already been called) ? I thought
>>that the lifecycle for composable would prevent this method being called
>>twice. Any reason ? If not, shouldn't we amend the doc, as most persons
>>
> will
> 
>>use this doc as their starting point (as I am ... :) ).
>>
>>Thanks
>>-Vincent
>>
>>
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> 
> 
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> .
> 
> 



-- 

"Those who would trade liberty for
  temporary security deserve neither"
                 - Benjamin Franklin


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