/*
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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.
*
* Copyright (c) 2001 - 2009 Object Refinery Ltd, Pentaho Corporation and Contributors.. All rights reserved.
*/
package org.pentaho.reporting.engine.classic.core.filter;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.engine.classic.core.Element;
import org.pentaho.reporting.engine.classic.core.function.ExpressionRuntime;
import org.pentaho.reporting.engine.classic.core.function.FormulaExpression;
/**
* A DataSource that can access values from the 'data-row'. The data-row contains all values from the current row of the
* report's <code>TableModel</code>, plus the current values of the defined expressions and functions for the report.
* <p/>
* The DataRowDataSource can either query the data-row directly using the specified field name or it can evaluate a
* given formula (which must be compatible to the OpenFormula specifications) to compute the value.
* <p/>
* Fields and formulas are mutually exclusive; defining a field name autmatically undefines the formula and vice versa.
*
* @author Thomas Morgner
* @see org.pentaho.reporting.engine.classic.core.DataRow
*/
public class DataRowDataSource implements DataSource
{
private static final Log logger = LogFactory.getLog(DataRowDataSource.class);
/**
* The field name that should be queried.
*/
private String field;
/**
* The formula-expression that computes the result value, if no field is given.
*/
private FormulaExpression valueExpression;
/**
* Default constructor.
* <p/>
* The expression name is empty ("", not null), the value initially null.
*/
public DataRowDataSource()
{
this(null);
}
/**
* Constructs a new data source.
*
* @param column the name of the field, function or expression in the data-row.
*/
public DataRowDataSource(final String column)
{
this.field = column;
}
/**
* @deprecated Required for legacy-parsing, do not use elsewhere.
*/
public String getField()
{
return getDataSourceColumnName();
}
/**
* @deprecated Required for legacy-parsing, do not use elsewhere.
* @param field
*/
public void setField(final String field)
{
setDataSourceColumnName(field);
}
/**
* Returns the data source column name.
*
* @return the column name.
*/
public String getDataSourceColumnName()
{
return field;
}
/**
* Defines the name of the column in the datarow to be queried.
*
* @param dataSourceColumnName the name of the column in the datarow to be queried.
* @throws NullPointerException if the name is <code>null</code>.
* @see org.pentaho.reporting.engine.classic.core.DataRow#get
*/
public void setDataSourceColumnName(final String dataSourceColumnName)
{
if (dataSourceColumnName == null)
{
throw new NullPointerException();
}
this.field = dataSourceColumnName;
if (valueExpression != null)
{
this.valueExpression.setFormula(null);
}
}
/**
* Returns the formula used to compute the value of the data source.
*
* @return the formula.
*/
public String getFormula()
{
if (valueExpression == null)
{
return null;
}
return valueExpression.getFormula();
}
/**
* Defines the formula used to compute the value of this data source.
*
* @param formula the formula for the data source.
*/
public void setFormula(final String formula)
{
if (formula == null)
{
throw new NullPointerException();
}
this.field = null;
if (valueExpression == null)
{
valueExpression = new FormulaExpression();
}
this.valueExpression.setFormula(formula);
if ("field".equals(valueExpression.getFormulaNamespace()))
{
DataRowDataSource.logger.warn(
"Encountered formula with 'field' prefix. Direct access to field-data should not be done using a formula. Auto-Fixing.");
this.field = valueExpression.getFormulaExpression();
this.valueExpression.setFormula(null);
}
}
/**
* Returns the current value of the data source, obtained from a particular column in the data-row.
*
* @param runtime the expression runtime that is used to evaluate formulas and expressions when computing the value of
* this filter.
* @param element
* @return the value.
*/
public Object getValue(final ExpressionRuntime runtime, final Element element)
{
if (runtime == null)
{
return null;
}
if (field != null)
{
return runtime.getDataRow().get(field);
}
if (valueExpression == null)
{
return null;
}
valueExpression.setRuntime(runtime);
try
{
return valueExpression.getValue();
}
catch (Exception e)
{
// ignore ..
return null;
}
finally
{
valueExpression.setRuntime(null);
}
}
/**
* Clones the data source. A previously registered report definition is not inherited to the clone.
*
* @return a clone.
* @throws CloneNotSupportedException if the cloning is not supported.
*/
public Object clone()
throws CloneNotSupportedException
{
final DataRowDataSource drs = (DataRowDataSource) super.clone();
if (valueExpression != null)
{
drs.valueExpression = (FormulaExpression) valueExpression.clone();
}
return drs;
}
}