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

   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: IfFunction.java 3521 2007-10-16 10:55:14Z tmorgner $
  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 IfFunction implements Function
  48: {
  49:   private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
  50: 
  51:   public IfFunction()
  52:   {
  53:   }
  54: 
  55:   public String getCanonicalName()
  56:   {
  57:     return "IF";
  58:   }
  59: 
  60:   public TypeValuePair evaluate(final FormulaContext context,
  61:                                 final ParameterCallback parameters)
  62:       throws EvaluationException
  63:   {
  64:     final int parameterCount = parameters.getParameterCount();
  65:     if (parameterCount < 2)
  66:     {
  67:       throw new EvaluationException(LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE);
  68:     }
  69: 
  70:     final Type conditionType = parameters.getType(0);
  71:     final Object conditionValue = parameters.getValue(0);
  72:     final Boolean condition = context.getTypeRegistry().convertToLogical(conditionType, conditionValue);
  73:     if(condition == null)
  74:     {
  75:       throw new EvaluationException(LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  76:     }
  77:     if (Boolean.TRUE.equals(condition))
  78:     {
  79:       final Object value = parameters.getValue(1);
  80:       final Type type = parameters.getType(1);
  81:       return new TypeValuePair(type, value);
  82:     }
  83:     // if condition is false and no third parameter, return false
  84:     if(parameterCount == 2 || parameters.getValue(2) == null)
  85:     {
  86:       return RETURN_FALSE;
  87:     }
  88:     // else return third parameter
  89:     final Object value = parameters.getValue(2);
  90:     final Type type = parameters.getType(2);
  91:     return new TypeValuePair(type, value);
  92:   }
  93: }