Re: [classad-users] Scope identifiers in the Java ClassAd library


Date: Tue, 20 Jul 2004 18:01:43 -0500 (CDT)
From: Alain Roy <roy@xxxxxxxxxxx>
Subject: Re: [classad-users] Scope identifiers in the Java ClassAd library
I have just started digging into the Java ClassAd code. From my 
preliminary diging, it seems like the bind(RecExpr ad1, RecExpr ad2) does 
the actual binding between the two ClassAds whereby "self" in ad1 referes 
to itself and "other" refers to ad2 and vice versa.
Yes, I believe you are right.

However the Condor manual mentions the scope identifiers to be "MY" and 
"TARGET" instead of "self" and "other".

Does this mean there is a difference in the C++ and Java implementation or 
is there some logic that I completely missed ?
No, but you missed another difference: The version of ClassAds used in 
Condor is not the same version in either the C++ or the Java libraries.

Here's a rough time line:

* Condor was created. ClassAds didn't exist, but the list of attributes you 
could have were in a C struct in the code.

* ClassAds were created. They were a huge improvement over the C struct, 
but the language was a bit sloppy.

* Rajesh Raman created "new ClassAds" which are much nicer and much more 
powerful, and got a Ph.D. out of it. This implementation is what you get in 
the C++ and Java distributions.

Condor has not yet adopted new ClassAds for technical reasons. It's one of 
my goals to switch Condor to new ClassAds, but it won't happen for a couple 
of months, probably.

We don't distribute the old ClassAd library, because it is so much less 
nice than the new ClassAd library. Besides, every minute we spend 
supporting it is a minute less that we spend getting the new ClassAds into 
Condor.

-alain

Condor Classads Info:
http://www.cs.wisc.edu/condor/classad/


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