Source for org.jfree.formula.operators.MinusSignOperator

   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: MinusSignOperator.java 2887 2007-06-06 17:07:52Z taqua $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.operators;
  32: 
  33: import java.math.BigDecimal;
  34: 
  35: import org.jfree.formula.EvaluationException;
  36: import org.jfree.formula.FormulaContext;
  37: import org.jfree.formula.LibFormulaErrorValue;
  38: import org.jfree.formula.lvalues.TypeValuePair;
  39: import org.jfree.formula.typing.Type;
  40: import org.jfree.formula.typing.TypeRegistry;
  41: 
  42: /**
  43:  * Creation-Date: 02.11.2006, 10:27:03
  44:  *
  45:  * @author Thomas Morgner
  46:  */
  47: public class MinusSignOperator implements PrefixOperator
  48: {
  49:   private static final BigDecimal ZERO = new BigDecimal(0);
  50: 
  51: 
  52:   public MinusSignOperator()
  53:   {
  54:   }
  55: 
  56:   public TypeValuePair evaluate(final FormulaContext context,
  57:                                 final TypeValuePair value1)
  58:       throws EvaluationException
  59:   {
  60:     final Type type = value1.getType();
  61:     final Object val = value1.getValue();
  62:     if (val == null)
  63:     {
  64:       throw new EvaluationException(LibFormulaErrorValue.ERROR_NA_VALUE);
  65:     }
  66:     
  67:     if (type.isFlagSet(Type.NUMERIC_TYPE))
  68:     {
  69:       final TypeRegistry typeRegistry = context.getTypeRegistry();
  70:       // return the same as zero minus value.
  71:       final Number number = typeRegistry.convertToNumber(type, val);
  72:       final BigDecimal value = getAsBigDecimal(number);
  73:       return new TypeValuePair(type, ZERO.subtract(value));
  74:     }
  75: 
  76:     if(val instanceof Number)
  77:     {
  78:       final BigDecimal value = getAsBigDecimal((Number)val);
  79:       return new TypeValuePair(type, ZERO.subtract(value));
  80:     }
  81: 
  82:     throw new EvaluationException
  83:         (LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE);
  84:   }
  85: 
  86:   private BigDecimal getAsBigDecimal(final Number number)
  87:   {
  88:     if (number instanceof BigDecimal)
  89:     {
  90:       return (BigDecimal) number;
  91:     }
  92:     return new BigDecimal(number.toString());
  93:   }
  94: 
  95:   public String toString()
  96:   {
  97:     return "-";
  98:   }
  99: }