Interface IExpressionEvaluator
-
- All Known Implementing Classes:
XBaseEvaluator
public interface IExpressionEvaluator
An expression evaluator is used to execute arbitrary Java code during pattern matching. In order to include the evaluation in the planning seemlessly it is expected from the evaluator implementors to report all used PVariables by name.
-
-
Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description java.lang.Object
evaluateExpression(IValueProvider provider)
The expression evaluator codejava.lang.Iterable<java.lang.String>
getInputParameterNames()
All input parameter names should be reported correctly.java.lang.String
getShortDescription()
A textual description of the expression.
-
-
-
Method Detail
-
getShortDescription
java.lang.String getShortDescription()
A textual description of the expression. Used only for debug purposes, but must not be null.
-
getInputParameterNames
java.lang.Iterable<java.lang.String> getInputParameterNames()
All input parameter names should be reported correctly.
-
evaluateExpression
java.lang.Object evaluateExpression(IValueProvider provider) throws java.lang.Exception
The expression evaluator code- Parameters:
provider
- the value provider is an engine-specific way of reading internal variable tuples to evaluate the expression with- Returns:
- the result of the expression: in case of predicate evaluation the return value must be true or false; otherwise the result can be an arbitrary object. No null values should be returned.
- Throws:
java.lang.Exception
-
-