Source for org.jfree.formula.lvalues.AbstractLValue

   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: AbstractLValue.java,v 1.4 2007/04/01 13:51:54 taqua Exp $
  28:  * ------------
  29:  * (C) Copyright 2006-2007, by Pentaho Corporation.
  30:  */
  31: package org.jfree.formula.lvalues;
  32: 
  33: import org.jfree.formula.FormulaContext;
  34: import org.jfree.formula.EvaluationException;
  35: import org.jfree.formula.typing.Type;
  36: 
  37: /**
  38:  * Creation-Date: 01.11.2006, 18:19:00
  39:  *
  40:  * @author Thomas Morgner
  41:  */
  42: public abstract class AbstractLValue implements LValue
  43: {
  44:   private static LValue[] EMPTY_CHILDS = new LValue[0];
  45: 
  46:   private transient FormulaContext context;
  47: 
  48:   protected AbstractLValue()
  49:   {
  50:   }
  51: 
  52:   public void initialize(FormulaContext context) throws EvaluationException
  53:   {
  54:     this.context = context;
  55:   }
  56: 
  57:   public FormulaContext getContext()
  58:   {
  59:     if (context == null) throw new NullPointerException();
  60:     return context;
  61:   }
  62: 
  63:   public Object clone() throws CloneNotSupportedException
  64:   {
  65:     return (AbstractLValue) super.clone();
  66:   }
  67: 
  68:   /**
  69:    * Returns any dependent lvalues (parameters and operands, mostly).
  70:    *
  71:    * @return
  72:    */
  73:   public LValue[] getChildValues()
  74:   {
  75:     return EMPTY_CHILDS;
  76:   }
  77: 
  78:   /**
  79:    * Querying the value type is only valid *after* the value has been
  80:    * evaluated.
  81:    *
  82:    * @return
  83:    */
  84:   public Type getValueType()
  85:   {
  86:     return null;
  87:   }
  88: }