/**
* ========================================
* JFreeReport : a free Java report library
* ========================================
*
* Project Info: http://reporting.pentaho.org/
*
* (C) Copyright 2000-2007, by Object Refinery Limited, Pentaho Corporation and Contributors.
*
* This library is free software; you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Foundation;
* either version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------
* $Id: FormulaExpression.java,v 1.6 2007/04/01 18:49:25 taqua Exp $
* ------------
* (C) Copyright 2000-2005, by Object Refinery Limited.
* (C) Copyright 2005-2007, by Pentaho Corporation.
*/
package org.jfree.report.expressions;
import org.jfree.formula.Formula;
import org.jfree.formula.FormulaContext;
import org.jfree.formula.parser.ParseException;
import org.jfree.report.DataSourceException;
import org.jfree.report.flow.ReportContext;
import org.jfree.util.Log;
/**
* Creation-Date: 04.11.2006, 19:24:04
*
* @author Thomas Morgner
*/
public class FormulaExpression extends AbstractExpression
{
private transient Formula compiledFormula;
private String formulaNamespace;
private String formulaExpression;
private String formula;
public FormulaExpression()
{
}
private synchronized FormulaContext getFormulaContext()
{
final ReportContext globalContext = getRuntime().getReportContext();
return globalContext.getFormulaContext();
}
public String getFormula()
{
return formula;
}
public String getFormulaNamespace()
{
return formulaNamespace;
}
public String getFormulaExpression()
{
return formulaExpression;
}
public void setFormula(final String formula)
{
this.formula = formula;
if (formula == null)
{
formulaNamespace = null;
formulaExpression = null;
}
else
{
final int separator = formula.indexOf(':');
if (separator <= 0 || ((separator + 1) == formula.length()))
{
if (formula.startsWith("="))
{
formulaNamespace = "report";
formulaExpression = formula.substring(1);
}
else
{
// error: invalid formula.
formulaNamespace = null;
formulaExpression = null;
}
}
else
{
formulaNamespace = formula.substring(0, separator);
formulaExpression = formula.substring(separator + 1);
}
}
this.compiledFormula = null;
}
private Object computeRegularValue()
{
try
{
if (compiledFormula == null)
{
compiledFormula = new Formula(formulaExpression);
}
final ReportFormulaContext context =
new ReportFormulaContext(getFormulaContext(), getDataRow());
try
{
compiledFormula.initialize(context);
return compiledFormula.evaluate();
}
finally
{
context.setDataRow(null);
}
}
catch (Exception e)
{
Log.debug("Failed to compute the regular value.", e);
return null;
}
}
/**
* Returns the compiled formula. The formula is not connected to a formula
* context.
*
* @return the formula.
* @throws ParseException if the formula contains syntax errors.
*/
public Formula getCompiledFormula()
throws ParseException
{
if (compiledFormula == null)
{
compiledFormula = new Formula(formulaExpression);
}
return compiledFormula;
}
/**
* Return the current expression value. <P> The value depends (obviously) on
* the expression implementation.
*
* @return the value of the function.
*/
public Object computeValue() throws DataSourceException
{
try
{
return computeRegularValue();
}
catch (Exception e)
{
return null;
}
}
/**
* Clones the expression, expression should be reinitialized after the
* cloning. <P> Expression maintain no state, cloning is done at the beginning
* of the report processing to disconnect the used expression from any other
* object space.
*
* @return A clone of this expression.
* @throws CloneNotSupportedException this should never happen.
*/
public Object clone() throws CloneNotSupportedException
{
final FormulaExpression o = (FormulaExpression) super.clone();
if (compiledFormula != null)
{
o.compiledFormula = (Formula) compiledFormula.clone();
}
return o;
}
}