View template modiifcations

[pc0202]

Part1 changes done:
Introduced new methods to

1. Field: getFunctioName(): String //parse function to get the function name from function field value
2. Field : getArgNames(): String[] //returns array of args name from function field value of this class
3. ViewTemplate :getExpression(String name) : String // return the result(expression) for a given function name
   Modified transformer method
   Added test cases
   deleted VTMain

Part 2 changes done-
Introduced IEvaluator: public T evaluate() and EvaluatorFactory: getInstance()

1. Impl classes added :- ProviderEvaluator and FunctionEvaluator
2. Added impl class SampleViewFunctionProvider (IViewFunctionProvider)
3. SampleViewFunctionProvider : doAction() called by ProviderEvaluator:evaluate()

[indrajra]

The toString here can still make 7 as "7", which is why we needed some other way.

[pc0202]

Now, JsonNodeFactory.instance.pojoNode(evaluator.evaluate()) using to set the object.

[indrajra]

Could there be a parameterized constructor?

[indrajra]

this is duplicate code repeated in tests...if you've to add a third test, you must think of creating functions for this.

[indrajra]

Can't allow EvaluatorFactory to be hardcoded with function names.

[indrajra]

MANDATORY: Why are these hardcoded here? We are creating a library and this can't be in a Factory class for sure.