Package 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.

Author:

cedric dot walter @ gmail dot com

Field Summary

Fields

Modifier and Type	Field	Description
static FreeRefFunction	instance

Constructor Summary

Constructors

Constructor	Description
Delta()

Method Summary

Modifier and Type	Method	Description
ValueEval	evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg1, ValueEval arg2)	see Function.evaluate(ValueEval[], int, int)
ValueEval	evaluate(ValueEval[] args, OperationEvaluationContext ec)

Methods inherited from class org.apache.poi.ss.formula.functions.Fixed2ArgFunction

evaluate

Methods inherited from class java.lang.Object

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

Field Detail

instance

public static final FreeRefFunction instance

Constructor Detail

Delta

public Delta()

Method Detail

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).