org.datanucleus.query.evaluator.memory
Class NullIfFunctionEvaluator

java.lang.Object
  org.datanucleus.query.evaluator.memory.NullIfFunctionEvaluator

All Implemented Interfaces:

InvocationEvaluator

public class NullIfFunctionEvaluator
extends java.lang.Object
implements InvocationEvaluator

Evaluator for the function NULLIF(numExpr, numExpr2). Returns null if the args are equal, otherwise returns the first arg.

Constructor Summary

NullIfFunctionEvaluator()

Method Summary

java.lang.Object	evaluate(InvokeExpression expr, java.lang.Object ignored, InMemoryExpressionEvaluator eval) Method to evaluate the InvokeExpression, as part of the overall evaluation defined by the InMemoryExpressionEvaluator.
protected java.lang.Object	getValueForArgExpression(Expression argExpr, InMemoryExpressionEvaluator eval)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NullIfFunctionEvaluator

public NullIfFunctionEvaluator()

Method Detail

evaluate

public java.lang.Object evaluate(InvokeExpression expr,
                                 java.lang.Object ignored,
                                 InMemoryExpressionEvaluator eval)

Description copied from interface: InvocationEvaluator

Method to evaluate the InvokeExpression, as part of the overall evaluation defined by the InMemoryExpressionEvaluator.

Specified by:

evaluate in interface InvocationEvaluator

Parameters:

expr - The expression for invocation

ignored - Value on which we are invoking

eval - The overall evaluator for in-memory

Returns:

The result

getValueForArgExpression

protected java.lang.Object getValueForArgExpression(Expression argExpr,
                                                    InMemoryExpressionEvaluator eval)