001 /**
002 * ========================================
003 * JFreeReport : a free Java report library
004 * ========================================
005 *
006 * Project Info: http://reporting.pentaho.org/
007 *
008 * (C) Copyright 2000-2007, by Object Refinery Limited, 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 * $Id: FormulaExpression.java,v 1.6 2007/04/01 18:49:25 taqua Exp $
027 * ------------
028 * (C) Copyright 2000-2005, by Object Refinery Limited.
029 * (C) Copyright 2005-2007, by Pentaho Corporation.
030 */
031
032 package org.jfree.report.expressions;
033
034 import org.jfree.formula.Formula;
035 import org.jfree.formula.FormulaContext;
036 import org.jfree.formula.parser.ParseException;
037 import org.jfree.report.DataSourceException;
038 import org.jfree.report.flow.ReportContext;
039 import org.jfree.util.Log;
040
041 /**
042 * Creation-Date: 04.11.2006, 19:24:04
043 *
044 * @author Thomas Morgner
045 */
046 public class FormulaExpression extends AbstractExpression
047 {
048 private transient Formula compiledFormula;
049 private String formulaNamespace;
050 private String formulaExpression;
051 private String formula;
052
053 public FormulaExpression()
054 {
055 }
056
057 private synchronized FormulaContext getFormulaContext()
058 {
059 final ReportContext globalContext = getRuntime().getReportContext();
060 return globalContext.getFormulaContext();
061 }
062
063 public String getFormula()
064 {
065 return formula;
066 }
067
068 public String getFormulaNamespace()
069 {
070 return formulaNamespace;
071 }
072
073 public String getFormulaExpression()
074 {
075 return formulaExpression;
076 }
077
078 public void setFormula(final String formula)
079 {
080 this.formula = formula;
081 if (formula == null)
082 {
083 formulaNamespace = null;
084 formulaExpression = null;
085 }
086 else
087 {
088 final int separator = formula.indexOf(':');
089 if (separator <= 0 || ((separator + 1) == formula.length()))
090 {
091 if (formula.startsWith("="))
092 {
093 formulaNamespace = "report";
094 formulaExpression = formula.substring(1);
095 }
096 else
097 {
098 // error: invalid formula.
099 formulaNamespace = null;
100 formulaExpression = null;
101 }
102 }
103 else
104 {
105 formulaNamespace = formula.substring(0, separator);
106 formulaExpression = formula.substring(separator + 1);
107 }
108 }
109 this.compiledFormula = null;
110 }
111
112 private Object computeRegularValue()
113 {
114 try
115 {
116 if (compiledFormula == null)
117 {
118 compiledFormula = new Formula(formulaExpression);
119 }
120
121 final ReportFormulaContext context =
122 new ReportFormulaContext(getFormulaContext(), getDataRow());
123 try
124 {
125 compiledFormula.initialize(context);
126 return compiledFormula.evaluate();
127 }
128 finally
129 {
130 context.setDataRow(null);
131 }
132 }
133 catch (Exception e)
134 {
135 Log.debug("Failed to compute the regular value.", e);
136 return null;
137 }
138 }
139
140 /**
141 * Returns the compiled formula. The formula is not connected to a formula
142 * context.
143 *
144 * @return the formula.
145 * @throws ParseException if the formula contains syntax errors.
146 */
147 public Formula getCompiledFormula()
148 throws ParseException
149 {
150 if (compiledFormula == null)
151 {
152 compiledFormula = new Formula(formulaExpression);
153 }
154 return compiledFormula;
155 }
156
157 /**
158 * Return the current expression value. <P> The value depends (obviously) on
159 * the expression implementation.
160 *
161 * @return the value of the function.
162 */
163 public Object computeValue() throws DataSourceException
164 {
165 try
166 {
167 return computeRegularValue();
168 }
169 catch (Exception e)
170 {
171 return null;
172 }
173 }
174
175 /**
176 * Clones the expression, expression should be reinitialized after the
177 * cloning. <P> Expression maintain no state, cloning is done at the beginning
178 * of the report processing to disconnect the used expression from any other
179 * object space.
180 *
181 * @return A clone of this expression.
182 * @throws CloneNotSupportedException this should never happen.
183 */
184 public Object clone() throws CloneNotSupportedException
185 {
186 final FormulaExpression o = (FormulaExpression) super.clone();
187 if (compiledFormula != null)
188 {
189 o.compiledFormula = (Formula) compiledFormula.clone();
190 }
191 return o;
192 }
193 }