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: FormulaFunction.java,v 1.8 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 package org.jfree.report.expressions;
032
033 import org.jfree.formula.Formula;
034 import org.jfree.formula.FormulaContext;
035 import org.jfree.formula.parser.ParseException;
036 import org.jfree.report.DataSourceException;
037 import org.jfree.report.flow.ReportContext;
038 import org.jfree.util.Log;
039
040 /**
041 * Creation-Date: 04.11.2006, 19:24:04
042 *
043 * @author Thomas Morgner
044 */
045 public class FormulaFunction extends AbstractExpression implements Function
046 {
047 private String formulaNamespace;
048 private String formulaExpression;
049 private String formula;
050
051 private String initialNamespace;
052 private String initialExpression;
053 private String initial;
054 private transient Formula compiledFormula;
055 private boolean initialized;
056
057 public FormulaFunction()
058 {
059 }
060
061 private synchronized FormulaContext getFormulaContext()
062 {
063 final ReportContext globalContext = getRuntime().getReportContext();
064 return globalContext.getFormulaContext();
065 }
066
067 public String getInitial()
068 {
069 return initial;
070 }
071
072 public String getInitialExpression()
073 {
074 return initialExpression;
075 }
076
077 public String getInitialNamespace()
078 {
079 return initialNamespace;
080 }
081
082 public void setInitial(final String initial)
083 {
084 this.initial = initial;
085 if (initial == null)
086 {
087 initialNamespace = null;
088 initialExpression = null;
089 }
090 else
091 {
092 final int separator = initial.indexOf(':');
093 if (separator <= 0 || ((separator + 1) == initial.length()))
094 {
095 if (formula.startsWith("="))
096 {
097 initialNamespace = "report";
098 initialExpression = initial.substring(1);
099 }
100 else
101 {
102 // error: invalid formula.
103 initialNamespace = null;
104 initialExpression = null;
105 }
106 }
107 else
108 {
109 initialNamespace = initial.substring(0, separator);
110 initialExpression = initial.substring(separator + 1);
111 }
112 }
113 }
114
115
116 public String getFormula()
117 {
118 return formula;
119 }
120
121 public String getFormulaNamespace()
122 {
123 return formulaNamespace;
124 }
125
126 public String getFormulaExpression()
127 {
128 return formulaExpression;
129 }
130
131 public void setFormula(final String formula)
132 {
133 this.formula = formula;
134 if (formula == null)
135 {
136 formulaNamespace = null;
137 formulaExpression = null;
138 }
139 else
140 {
141 final int separator = formula.indexOf(':');
142 if (separator <= 0 || ((separator + 1) == formula.length()))
143 {
144 if (formula.startsWith("="))
145 {
146 formulaNamespace = "report";
147 formulaExpression = formula.substring(1);
148 }
149 else
150 {
151 // error: invalid formula.
152 formulaNamespace = null;
153 formulaExpression = null;
154 }
155 }
156 else
157 {
158 formulaNamespace = formula.substring(0, separator);
159 formulaExpression = formula.substring(separator + 1);
160 }
161 }
162 this.compiledFormula = null;
163 }
164
165 /**
166 * When the advance method is called, the function is asked to perform the
167 * next step of its computation.
168 * <p/>
169 * The original function must not be altered during that step (or more
170 * correctly, calling advance on the original expression again must not return
171 * a different result).
172 *
173 * @return a copy of the function containing the new state.
174 */
175 public Function advance() throws DataSourceException
176 {
177 try
178 {
179 return (Function) clone();
180 }
181 catch (CloneNotSupportedException e)
182 {
183 throw new DataSourceException("Unable to derive a new instance");
184 }
185 }
186
187 private Object computeInitialValue()
188 {
189 try
190 {
191 if (initial != null)
192 {
193 final Formula initFormula = new Formula(initialExpression);
194 final ReportFormulaContext context =
195 new ReportFormulaContext(getFormulaContext(), getDataRow());
196 context.setDeclaringElement(getRuntime().getDeclaringParent());
197 try
198 {
199 initFormula.initialize(context);
200 return initFormula.evaluate();
201 }
202 finally
203 {
204 context.setDeclaringElement(null);
205 context.setDataRow(null);
206 }
207 }
208
209 // if the code above did not trigger, compute a regular thing ..
210 return computeRegularValue();
211 }
212 catch (Exception e)
213 {
214 Log.debug ("Failed to compute the initial value.");
215 return null;
216 }
217 }
218
219 private Object computeRegularValue()
220 {
221 try
222 {
223 if (compiledFormula == null)
224 {
225 compiledFormula = new Formula(formulaExpression);
226 }
227
228 final ReportFormulaContext context =
229 new ReportFormulaContext(getFormulaContext(), getDataRow());
230 context.setDeclaringElement(getRuntime().getDeclaringParent());
231 try
232 {
233 compiledFormula.initialize(context);
234 return compiledFormula.evaluate();
235 }
236 finally
237 {
238 context.setDeclaringElement(null);
239 context.setDataRow(null);
240 }
241 }
242 catch (Exception e)
243 {
244 Log.debug ("Failed to compute the regular value.", e);
245 return null;
246 }
247 }
248
249 /**
250 * Return the current expression value. <P> The value depends (obviously) on
251 * the expression implementation.
252 *
253 * @return the value of the function.
254 */
255 public Object computeValue() throws DataSourceException
256 {
257 try
258 {
259 if (initialized == false)
260 {
261 initialized = true;
262 return computeInitialValue();
263 }
264 return computeRegularValue();
265 }
266 catch (Exception e)
267 {
268 return null;
269 }
270 }
271
272 /**
273 * Clones the expression, expression should be reinitialized after the
274 * cloning. <P> Expression maintain no state, cloning is done at the beginning
275 * of the report processing to disconnect the used expression from any other
276 * object space.
277 *
278 * @return A clone of this expression.
279 * @throws CloneNotSupportedException this should never happen.
280 */
281 public Object clone() throws CloneNotSupportedException
282 {
283 final FormulaFunction o = (FormulaFunction) super.clone();
284 if (compiledFormula != null)
285 {
286 o.compiledFormula = (Formula) compiledFormula.clone();
287 }
288 return o;
289 }
290
291
292 /**
293 * Returns the compiled formula. The formula is not connected to a formula
294 * context.
295 *
296 * @return the formula.
297 * @throws org.jfree.formula.parser.ParseException if the formula contains syntax errors.
298 */
299 public Formula getCompiledFormula()
300 throws ParseException
301 {
302 if (compiledFormula == null)
303 {
304 compiledFormula = new Formula(formulaExpression);
305 }
306 return compiledFormula;
307 }
308 }