Adding a more robust Criteria interface. about mango

[cjnolet]

After discussions with various individuals, I'd like to make sure we still have the ability to apply this generic criteria to both batch queries and use "matches()" to verify it against streaming data. That's an extremely powerful feature. The current design means quite a bit of code needs to be changed when new criteria elements are added (such as regex) and it'd be nice to whittle that down a bit. I'm not seeing too many performance issues with the current implementation because generally the visitors (for validating and optimizating) only get done once when the query is sent to the service that's going to be applying it.

[eawagner]

What I mean by performance issues is for evaluating criteria. Currently the only way that can be done is to hook in a visitor that knows how to evaluate all of your criteria. This evaluation would need to be done every time here is a new event in the stream.

Only the optimization and validation needs to be done once.

[cjnolet]

I mean, right now there's a single optimization that happens with the Node tree before it is turned into the Criteria. The purpose for that is so optimizations can be done once and the resulting Criteria tree can be matched against directly.

[eawagner]

With the new Predicate Criteria, the performance concern isn't an issue. That was mostly related to using the visitor pattern to allow for evaluation of the criteria to return a true/false in a boolean expression tree.