Package org.datanucleus.store.query.inmemory.method

Class NullIfFunction

java.lang.Object

org.datanucleus.store.query.inmemory.method.NullIfFunction

All Implemented Interfaces:

InvocationEvaluator

public class NullIfFunction
extends Object
implements InvocationEvaluator

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

Constructor Summary

Constructors

Constructor	Description
NullIfFunction()

Method Summary

Modifier and Type	Method	Description
Object	evaluate(InvokeExpression expr, Object ignored, InMemoryExpressionEvaluator eval)	Method to evaluate the InvokeExpression, as part of the overall evaluation defined by the InMemoryExpressionEvaluator.
protected 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

NullIfFunction

public NullIfFunction()

Method Detail

evaluate

public Object evaluate(InvokeExpression expr,
                       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 Object getValueForArgExpression(Expression argExpr,
                                          InMemoryExpressionEvaluator eval)