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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: ContextLookup.java,v 1.7 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.typing.Type; 34: import org.jfree.formula.FormulaContext; 35: import org.jfree.formula.EvaluationException; 36: 37: /** 38: * A reference that queries the datarow. 39: * 40: * @author Thomas Morgner 41: */ 42: public class ContextLookup extends AbstractLValue 43: { 44: private String name; 45: 46: public ContextLookup(final String name) 47: { 48: this.name = name; 49: } 50: 51: public TypeValuePair evaluate() throws EvaluationException 52: { 53: final FormulaContext context = getContext(); 54: final Object value = context.resolveReference(name); 55: final Type type = context.resolveReferenceType(name); 56: return new TypeValuePair(type, value); 57: } 58: 59: 60: public String toString() 61: { 62: return "[" + name + "]"; 63: } 64: 65: /** 66: * Checks, whether the LValue is constant. Constant lvalues always return the 67: * same value. 68: * 69: * @return 70: */ 71: public boolean isConstant() 72: { 73: return false; 74: } 75: 76: public String getName() 77: { 78: return name; 79: } 80: }