Source for org.jfree.formula.lvalues.PrefixTerm

   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: PrefixTerm.java 2780 2007-05-07 22:51:12Z mimil $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.lvalues;
  32: 
  33: import org.jfree.formula.operators.PrefixOperator;
  34: import org.jfree.formula.EvaluationException;
  35: 
  36: /**
  37:  * Creation-Date: 02.11.2006, 10:20:27
  38:  *
  39:  * @author Thomas Morgner
  40:  */
  41: public class PrefixTerm extends AbstractLValue
  42: {
  43:   private PrefixOperator operator;
  44:   private LValue value;
  45: 
  46:   public PrefixTerm(final PrefixOperator operator, final LValue value)
  47:   {
  48:     if (operator == null)
  49:     {
  50:       throw new NullPointerException();
  51:     }
  52:     if (value == null)
  53:     {
  54:       throw new NullPointerException();
  55:     }
  56: 
  57:     this.operator = operator;
  58:     this.value = value;
  59:   }
  60: 
  61:   public PrefixOperator getOperator()
  62:   {
  63:     return operator;
  64:   }
  65: 
  66:   public LValue getValue()
  67:   {
  68:     return value;
  69:   }
  70: 
  71: 
  72:   public TypeValuePair evaluate() throws EvaluationException
  73:   {
  74:     return operator.evaluate(getContext(), value.evaluate());
  75:   }
  76: 
  77: 
  78:   public String toString()
  79:   {
  80:     return "(" + operator + value + ")";
  81:   }
  82: 
  83:   /**
  84:    * Returns any dependent lvalues (parameters and operands, mostly).
  85:    *
  86:    * @return
  87:    */
  88:   public LValue[] getChildValues()
  89:   {
  90:     return new LValue[]{ value };
  91:   }
  92: 
  93:   /**
  94:    * Checks, whether the LValue is constant. Constant lvalues always return the
  95:    * same value.
  96:    *
  97:    * @return
  98:    */
  99:   public boolean isConstant()
 100:   {
 101:     return value.isConstant();
 102:   }
 103: 
 104:   public Object clone() throws CloneNotSupportedException
 105:   {
 106:     final PrefixTerm o = (PrefixTerm) super.clone();
 107:     o.value = (LValue) value.clone();
 108:     return o;
 109:   }
 110: }