Source for org.jfree.formula.operators.AbstractCompareOperator

   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: AbstractCompareOperator.java 3522 2007-10-16 10:56:57Z tmorgner $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: 
  32: package org.jfree.formula.operators;
  33: 
  34: import org.jfree.formula.lvalues.TypeValuePair;
  35: import org.jfree.formula.FormulaContext;
  36: import org.jfree.formula.EvaluationException;
  37: import org.jfree.formula.LibFormulaErrorValue;
  38: import org.jfree.formula.typing.TypeRegistry;
  39: import org.jfree.formula.typing.Type;
  40: import org.jfree.formula.typing.ExtendedComparator;
  41: import org.jfree.formula.typing.coretypes.LogicalType;
  42: 
  43: /**
  44:  * Creation-Date: 06.06.2007, 18:52:25
  45:  *
  46:  * @author Thomas Morgner
  47:  */
  48: public abstract class AbstractCompareOperator implements InfixOperator
  49: {
  50:   private static final TypeValuePair RETURN_TRUE = new TypeValuePair(LogicalType.TYPE, Boolean.TRUE);
  51:   private static final TypeValuePair RETURN_FALSE = new TypeValuePair(LogicalType.TYPE, Boolean.FALSE);
  52: 
  53:   public AbstractCompareOperator()
  54:   {
  55:   }
  56: 
  57:   public final TypeValuePair evaluate(final FormulaContext context,
  58:                                       final TypeValuePair value1,
  59:                                       final TypeValuePair value2)
  60:       throws EvaluationException
  61:   {
  62:     final TypeRegistry typeRegistry = context.getTypeRegistry();
  63:     final Type type1 = value1.getType();
  64:     final Type type2 = value2.getType();
  65:     final Object value1Raw = value1.getValue();
  66:     final Object value2Raw = value2.getValue();
  67:     if (value1Raw == null || value2Raw == null)
  68:     {
  69:       throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE);
  70:     }
  71: 
  72:     final ExtendedComparator comparator = typeRegistry.getComparator(type1, type2);
  73:     final Integer result = comparator.compare (type1, value1Raw, type2, value2Raw);
  74:     if (result == null)
  75:     {
  76:       throw new EvaluationException
  77:           (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  78:     }
  79: 
  80:     if (evaluate(result.intValue()))
  81:     {
  82:       return RETURN_TRUE;
  83:     }
  84:     return RETURN_FALSE;
  85:   }
  86: 
  87:   protected abstract boolean evaluate(int compareResult);
  88: }