Source for org.jfree.formula.function.logical.XorFunction

   1: /**
   2:  * =========================================
   3:  * LibFormula : a free Java formula library
   4:  * =========================================
   5:  *
   6:  * Project Info:  http://reporting.pentaho.org/libformula/
   7:  *
   8:  * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
   9:  *
  10:  * This library is free software; you can redistribute it and/or modify it under the terms
  11:  * of the GNU Lesser General Public License as published by the Free Software Foundation;
  12:  * either version 2.1 of the License, or (at your option) any later version.
  13:  *
  14:  * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
  15:  * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  16:  * See the GNU Lesser General Public License for more details.
  17:  *
  18:  * You should have received a copy of the GNU Lesser General Public License along with this
  19:  * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  20:  * Boston, MA 02111-1307, USA.
  21:  *
  22:  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
  23:  * in the United States and other countries.]
  24:  *
  25:  *
  26:  * ------------
  27:  * $Id: XorFunction.java,v 1.7 2007/04/01 13:51:53 taqua Exp $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.function.logical;
  32: 
  33: import org.jfree.formula.EvaluationException;
  34: import org.jfree.formula.FormulaContext;
  35: import org.jfree.formula.LibFormulaErrorValue;
  36: import org.jfree.formula.function.Function;
  37: import org.jfree.formula.function.ParameterCallback;
  38: import org.jfree.formula.lvalues.TypeValuePair;
  39: import org.jfree.formula.typing.Type;
  40: import org.jfree.formula.typing.coretypes.LogicalType;
  41: 
  42: /**
  43:  * Creation-Date: 04.11.2006, 18:28:15
  44:  *
  45:  * @author Thomas Morgner
  46:  */
  47: public class XorFunction implements Function
  48: {
  49:   private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
  50:   private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
  51: 
  52: 
  53:   public XorFunction()
  54:   {
  55:   }
  56: 
  57:   public String getCanonicalName()
  58:   {
  59:     return "XOR";
  60:   }
  61: 
  62: 
  63:   public TypeValuePair evaluate(FormulaContext context,
  64:                                 ParameterCallback parameters)
  65:       throws EvaluationException
  66:   {
  67:     if(parameters.getParameterCount() < 1)
  68:     {
  69:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  70:     }
  71:     int count = 0;
  72:     final int parameterCount = parameters.getParameterCount();
  73:     for (int i = 0; i < parameterCount; i++)
  74:     {
  75:       final Type conditionType = parameters.getType(i);
  76:       final Object conditionValue = parameters.getValue(i);
  77:       final Boolean condition = context.getTypeRegistry().convertToLogical(conditionType, conditionValue);
  78:       if(condition == null)
  79:       {
  80:         throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  81:       }
  82:       if (Boolean.TRUE.equals(condition))
  83:       {
  84:         count += 1;
  85:       }
  86:     }
  87:     if (count == 1)
  88:     {
  89:       return RETURN_TRUE;
  90:     }
  91:     else
  92:     {
  93:       return RETURN_FALSE;
  94:     }
  95: 
  96:   }
  97: }