org.apache.poi.ss.formula.functions
Class Delta

java.lang.Object
  org.apache.poi.ss.formula.functions.Fixed2ArgFunction
      org.apache.poi.ss.formula.functions.Delta

All Implemented Interfaces:

FreeRefFunction, Function, Function2Arg

public final class Delta
extends Fixed2ArgFunction
implements FreeRefFunction

Implementation for Excel DELTA() function.

Syntax:
DELTA (number1,number2 )

Tests whether two values are equal. Returns 1 if number1 = number2; returns 0 otherwise. Use this function to filter a set of values. For example, by summing several DELTA functions you calculate the count of equal pairs. This function is also known as the Kronecker Delta function.

• If number1 is nonnumeric, DELTA returns the #VALUE! error value.
• If number2 is nonnumeric, DELTA returns the #VALUE! error value.

instance

public static final FreeRefFunction instance

Delta

public Delta()

evaluate

public ValueEval evaluate(int srcRowIndex,
                          int srcColumnIndex,
                          ValueEval arg1,
                          ValueEval arg2)

Description copied from interface: Function2Arg

see Function.evaluate(ValueEval[], int, int)

Specified by:

evaluate in interface Function2Arg

evaluate

public ValueEval evaluate(ValueEval[] args,
                          OperationEvaluationContext ec)

Specified by:

evaluate in interface FreeRefFunction

Parameters:

args - the pre-evaluated arguments for this function. args is never null, nor are any of its elements.

ec - primarily used to identify the source cell containing the formula being evaluated. may also be used to dynamically create reference evals.

Returns:

never null. Possibly an instance of ErrorEval in the case of a specified Excel error (Exceptions are never thrown to represent Excel errors).