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 }