[jbpm-dev] [jBPM Development] - Re: parser for each jpdl release

[tom.baeyens@jboss.com]

"camunda" wrote : Depends on how good we can develop these new parsers. I think of fixes in parsing for older released, where complexity might explode if you have to have a look at a couple of versions.
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after an attempt i did yesterday, I realized having a parser-per-version gets much more trickier then I originally thought.

"camunda" wrote : Hmm, and you changed, you want to ADD namespaces per default???? ;-)

not really.  

basically one of the techniques that we could use is the following:  upon deploying the process, we could 
* parse the process into dom
* if no namespace is present to indicate the version, we could add a namespace declaration or another attribute that indicates the version
* then serialize that process 
* and update the xml in the deployment before it gets saved

in general we could potentially add or change the xml when we deploy it.  but I think that a downside will be that developers don't like this because they will love it better if they still recognize their own XML in the DB.

the alternative is that we leverage the properties that are associated to a deployment object.

"camunda" wrote : A basic question upfront: Why not forbit removing attributes from the schema at all? Shouldn't be that regular and not hard to avoid, or am I wrong here? Would save us all that complexity...
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here's the dilemma:

attribute 'expr' is used in conditions on transitions in a decision.  in that case the returned value is expected to be a boolean.

the 'expr' attribute is also used in one of the places where you specify user code.  in that case the resulting object is used as the user defined object.

now I want to clean that up:

1) i want to keep 

2) i want to make all the user code parsing consistent.  in order not to clash with the expr of condition, I want to use object-expr for all usages where the resulting object is used as user code.

i don't see how we can clean this up without differentiating the parsing between versions.

in the meantime i do think that we should be able to support this with just a couple of if-then-else statements in the single parser based on the namespace or version info.

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