Module datarush.library
Package com.pervasive.datarush.functions

Class EvaluationContext

java.lang.Object
com.pervasive.datarush.functions.EvaluationContext
public class EvaluationContext extends Object
An object describing the context in which a subexpression of a larger expression is being evaluated. The context captures global information pertaining to the top-level expression containing the subexpression.

  • Constructor Details

    • EvaluationContext

      public EvaluationContext(RecordValued input)

  • Method Details

    • getInput

      public RecordValued getInput()
      Gets the input record used for the top-level expression.
      Returns:

    • createMemoizingEvaluator

      public FunctionEvaluator createMemoizingEvaluator(FunctionEvaluator f)
      Creates an evaluator for the top-level expression which memoizes subexpression values.
      Parameters:
      f - the top-level evaluator
      Returns:
      an evaluator caching intermediate results

    • constructEvaluator

      public FunctionEvaluator constructEvaluator(EvaluatorFactory factory, List<Object> arguments, ScalarSettable result)
      Creates an evaluator for a top-level expression, binding its output to the provided result buffer.
      Parameters:
      factory - a factory for constructing the top-level function
      arguments - the arguments to pass to the function evaluator
      result - the buffer into which evaluation results are to be written
      Returns:
      a new evaluator

    • constructSubexpressionEvaluation

      public ScalarValued constructSubexpressionEvaluation(EvaluatorFactory factory, List<Object> arguments, ScalarTokenType resultType)
      Creates an evaluation of a subexpression which can be used as input to the evaluator of the expression containing it.
      Parameters:
      factory - a factory for constructing the subexpression function
      arguments - the arguments to pass to the function evaluator
      Returns:
      an object containing the current value of the subexpression