Bug 136553 [regression]Preview error when set invalid group interval.
Description: Preview error when set invalid group interval. Steps to reproduce: 1. Insert a table 2. Add a group on number column, set interval to Year,1 3. Preview 4. Edit group on string column set interval to Prefix,1 5. Preview Expected result: Error msg about invalid group interval. Actual result: Error happened while running the report
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/DteDataEngine.java
* Contributors:
 *  Actuate Corporation  - initial API and implementation
 *******************************************************************************/
package org.eclipse.birt.report.engine.data.dte;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import org.eclipse.birt.core.exception.BirtException;
import org.eclipse.birt.data.engine.api.DataEngine;
import org.eclipse.birt.data.engine.api.DataEngineContext;
import org.eclipse.birt.data.engine.api.IBaseQueryDefinition;
import org.eclipse.birt.data.engine.api.IPreparedQuery;
import org.eclipse.birt.data.engine.api.IQueryDefinition;
import org.eclipse.birt.data.engine.api.IQueryResults;
import org.eclipse.birt.report.engine.data.IResultSet;
import org.eclipse.birt.report.engine.executor.ExecutionContext;
import org.eclipse.birt.report.engine.ir.Report;
import org.mozilla.javascript.Scriptable;
/**
 * implments IDataEngine interface, using birt's data transformation engine
 * (DtE)
 * 
 * @version $Revision: 1.36 $ $Date: 2006/01/20 08:00:55 $
 */
public class DteDataEngine extends AbstractDataEngine
{
	/*
	 * need not be stored in report document.
	 */