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From "James Mitchell" <>
Subject Re: [chain] LookupCommand's return value
Date Thu, 17 Feb 2005 04:52:45 GMT
I'm just now catching up on some of this....but I was wondering.....if you 
configure "ignoreReturnValue" or "abortIfContextValueTrueOrNull" or 
"whatchaMaCallit", then how would you (in a looked up chain) tell the 
calling chain to abort without having to throw an exception?

James Mitchell
Software Engineer / Open Source Evangelist
EdgeTech, Inc.
AIM: jmitchtx

----- Original Message ----- 
From: "Joe Germuska" <>
To: "Craig McClanahan" <>; "Jakarta Commons Developers 
List" <>; "Sean Schofield" 
Sent: Wednesday, February 16, 2005 12:48 PM
Subject: Re: [chain] LookupCommand's return value

> At 9:23 AM -0800 2/16/05, Craig McClanahan wrote:
>>On Wed, 16 Feb 2005 08:08:14 -0500, Sean Schofield
>><> wrote:
>>>  > I'm just hesitant to add a new dependency on my own whim.  JEXL isn't
>>>  > very heavy (132 K) but I think people are keen on keeping Chain light
>>>  > too.
>>>  Keeping chain light would be nice.  I don't know too much about JEXL
>>>  personally although I will be investigating it shortly as an
>>>  alternative to Velocity for some template stuff I have.  How would you
>>>  propose doing it if you didn't use JEXL?
>>>  > Joe
>>Digester has some limited parameter substitution capabilities that
>>could be applied when the chain configuration is being parsed.  Is
>>that enough to satisfy the kinds of things you're thinking of that
>>might want expressions?
> I don't think so, since I'm specifically interested in runtime state. "Is 
> the ActionForm in *this* context valid?"   "Look up the command with the 
> name matching the value of the 'path' property of the current 
> ForwardConfig."  "Look up and execute a command only if the current value 
> of context property "unitsOrdered" is greater than 1000."
> Again, for some or all of these, one could probably manage with judicious 
> use of CopyCommand and LookupCommand, possibly augmented by some very 
> simple compiled Java commands which might have properties for some 
> configurability.
> If there's hesitation to formally add any external dependency to the 
> project, then when I get around to writing some of these, I'll just put 
> them up somewhere and invite people to have a look.  If people don't feel 
> that a compile-time dependency on JEXL (which is small and which has seen 
> a 1.0 release) is too great a burden, then I'll do them directly in the 
> repository in a package which clearly separates them from the 
> dependency-free classes (org.apache.commons.chain.impl.expr or 
> org.apache.commons.chain.impl.jexl).
> Joe
> -- 
> Joe Germuska   
> "Narrow minds are weapons made for mass destruction"  -The Ex
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