Bug 188336 Fairly Simple Report Generates NPE When Saving as Excel
When attempting to Save the attached report to Excel, the following error is displayed in the viewer instead of the Excel file: + org.eclipse.birt.report.service.api.ReportServiceException: Error happened while running the report; nested exception is: java.util.EmptyStackException
engine/org.eclipse.birt.report.engine.emitter.prototype.excel/src/org/eclipse/birt/report/engine/emitter/excel/ExcelEmitter.java
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	public void startTableBand( ITableBandContent band )
	{
	}
	/**
	 * Add table's group information
	 * @param group
	 * 			current table group
	 */
	public void startTableGroup( ITableGroupContent group )
	{
		GroupInfo parent = (GroupInfo) groupInfos.peek( );
		String groupName = ( (TableGroupDesign) group.getGenerateBy( ) )
				.getName( );
		
		GroupInfo child = new GroupInfo( groupName, parent.getColExps( ) );
		parent.addSubGroupInfo( child );
		groupInfos.push( child );
	}
	public void startText( ITextContent text )
	{
	}
	/**
	 * Add an element's data to container.
	 * 
	 * @param design
	 *            element's design
	 * @param style
	 *            element's style
	 * @param url