/* ==================================================================== | |
Licensed to the Apache Software Foundation (ASF) under one or more | |
contributor license agreements. See the NOTICE file distributed with | |
this work for additional information regarding copyright ownership. | |
The ASF licenses this file to You under the Apache License, Version 2.0 | |
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http://www.apache.org/licenses/LICENSE-2.0 | |
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distributed under the License is distributed on an "AS IS" BASIS, | |
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package org.apache.poi.ss.formula.functions; | |
import org.apache.poi.ss.formula.OperationEvaluationContext; | |
import org.apache.poi.ss.formula.eval.*; | |
import java.math.BigDecimal; | |
/** | |
* Implementation for Excel DELTA() function.<p/> | |
* <p/> | |
* <b>Syntax</b>:<br/> <b>DELTA </b>(<b>number1</b>,<b>number2</b> )<br/> | |
* <p/> | |
* 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. | |
* | |
* <ul> | |
* <li>If number1 is nonnumeric, DELTA returns the #VALUE! error value.</li> | |
* <li>If number2 is nonnumeric, DELTA returns the #VALUE! error value.</li> | |
* </ul> | |
* | |
* @author cedric dot walter @ gmail dot com | |
*/ | |
public final class Delta extends Fixed2ArgFunction implements FreeRefFunction { | |
public static final FreeRefFunction instance = new Delta(); | |
private final static NumberEval ONE = new NumberEval(1); | |
private final static NumberEval ZERO = new NumberEval(0); | |
public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg1, ValueEval arg2) { | |
ValueEval veText1; | |
try { | |
veText1 = OperandResolver.getSingleValue(arg1, srcRowIndex, srcColumnIndex); | |
} catch (EvaluationException e) { | |
return e.getErrorEval(); | |
} | |
String strText1 = OperandResolver.coerceValueToString(veText1); | |
Double number1 = OperandResolver.parseDouble(strText1); | |
if (number1 == null) { | |
return ErrorEval.VALUE_INVALID; | |
} | |
ValueEval veText2; | |
try { | |
veText2 = OperandResolver.getSingleValue(arg2, srcRowIndex, srcColumnIndex); | |
} catch (EvaluationException e) { | |
return e.getErrorEval(); | |
} | |
String strText2 = OperandResolver.coerceValueToString(veText2); | |
Double number2 = OperandResolver.parseDouble(strText2); | |
if (number2 == null) { | |
return ErrorEval.VALUE_INVALID; | |
} | |
int result = new BigDecimal(number1.doubleValue()).compareTo(new BigDecimal(number2.doubleValue())); | |
return result == 0 ? ONE : ZERO; | |
} | |
public ValueEval evaluate(ValueEval[] args, OperationEvaluationContext ec) { | |
if (args.length == 2) { | |
return evaluate(ec.getRowIndex(), ec.getColumnIndex(), args[0], args[1]); | |
} | |
return ErrorEval.VALUE_INVALID; | |
} | |
} |