| /* ==================================================================== |
| 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 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| ==================================================================== */ |
| |
| package org.apache.poi.ss.formula.functions; |
| |
| import org.apache.poi.ss.formula.OperationEvaluationContext; |
| import org.apache.poi.ss.formula.eval.ErrorEval; |
| import org.apache.poi.ss.formula.eval.EvaluationException; |
| import org.apache.poi.ss.formula.eval.NumberEval; |
| import org.apache.poi.ss.formula.eval.OperandResolver; |
| import org.apache.poi.ss.formula.eval.ValueEval; |
| |
| /** |
| * 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 static final NumberEval ONE = new NumberEval(1); |
| private static final NumberEval ZERO = new NumberEval(0); |
| |
| public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg1, ValueEval arg2) { |
| try { |
| Double number1 = evaluateValue(arg1, srcRowIndex, srcColumnIndex); |
| if (number1 == null) { |
| return ErrorEval.VALUE_INVALID; |
| } |
| Double number2 = evaluateValue(arg2, srcRowIndex, srcColumnIndex); |
| if (number2 == null) { |
| return ErrorEval.VALUE_INVALID; |
| } |
| |
| return (number1.compareTo(number2) == 0) ? ONE : ZERO; |
| } catch (EvaluationException e) { |
| return e.getErrorEval(); |
| } |
| } |
| |
| 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; |
| } |
| |
| private static Double evaluateValue(ValueEval arg, int srcRowIndex, int srcColumnIndex) throws EvaluationException { |
| ValueEval veText = OperandResolver.getSingleValue(arg, srcRowIndex, srcColumnIndex); |
| String strText1 = OperandResolver.coerceValueToString(veText); |
| return OperandResolver.parseDouble(strText1); |
| } |
| } |