001 /**
002 * =========================================
003 * LibFormula : a free Java formula library
004 * =========================================
005 *
006 * Project Info: http://reporting.pentaho.org/libformula/
007 *
008 * (C) Copyright 2006-2007, by Pentaho Corporation and Contributors.
009 *
010 * This library is free software; you can redistribute it and/or modify it under the terms
011 * of the GNU Lesser General Public License as published by the Free Software Foundation;
012 * either version 2.1 of the License, or (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
015 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
016 * See the GNU Lesser General Public License for more details.
017 *
018 * You should have received a copy of the GNU Lesser General Public License along with this
019 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
020 * Boston, MA 02111-1307, USA.
021 *
022 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
023 * in the United States and other countries.]
024 *
025 *
026 * ------------
027 * $Id: AbstractLValue.java 3521 2007-10-16 10:55:14Z tmorgner $
028 * ------------
029 * (C) Copyright 2006-2007, by Pentaho Corporation.
030 */
031 package org.jfree.formula.lvalues;
032
033 import org.jfree.formula.FormulaContext;
034 import org.jfree.formula.EvaluationException;
035 import org.jfree.formula.typing.Type;
036
037 /**
038 * Creation-Date: 01.11.2006, 18:19:00
039 *
040 * @author Thomas Morgner
041 */
042 public abstract class AbstractLValue implements LValue
043 {
044 private static final LValue[] EMPTY_CHILDS = new LValue[0];
045
046 private transient FormulaContext context;
047
048 protected AbstractLValue()
049 {
050 }
051
052 public void initialize(final FormulaContext context) throws EvaluationException
053 {
054 this.context = context;
055 }
056
057 public FormulaContext getContext()
058 {
059 if (context == null)
060 {
061 throw new NullPointerException();
062 }
063 return context;
064 }
065
066 public Object clone() throws CloneNotSupportedException
067 {
068 return super.clone();
069 }
070
071 /**
072 * Returns any dependent lvalues (parameters and operands, mostly).
073 *
074 * @return
075 */
076 public LValue[] getChildValues()
077 {
078 return EMPTY_CHILDS;
079 }
080
081 /**
082 * Querying the value type is only valid *after* the value has been
083 * evaluated.
084 *
085 * @return
086 */
087 public Type getValueType()
088 {
089 return null;
090 }
091 }