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
.getDesign( ).getReportDesign( ) );
			convert.html2Content( foreign );
			startCase( foreign );			
			ContentEmitterVisitor contentVisitor = new ContentEmitterVisitor(
					this );
			contentVisitor.visitChildren( foreign, null );
			endCase();
		}
	}
	public void startGroup( IGroupContent group )
	{
	}
	/**
	 * If the image is generaged by chart, get the chart data and store them
	 * @param image
	 * 				iamge element
	 */
	public void startImage( IImageContent image )
	{
		if ( image.getGenerateBy( ) instanceof ExtendedItemDesign )
		{
			ExtendedItemDesign eitem = (ExtendedItemDesign) image
					.getGenerateBy( );
			ExtendedItemHandle handle = (ExtendedItemHandle) eitem.getHandle( );
			String tagName = handle.getExtensionName( );
			if ( "chart".equalsIgnoreCase( tagName ) )
			{
				File res = chartConverter.convert( eitem, handle );
				if ( res != null )
				{