Bug 181704 Exception is thrown out when preview the attached design file as XLS PROTOTYPE [1203]
engine/org.eclipse.birt.report.engine.emitter.prototype.excel/src/org/eclipse/birt/report/engine/emitter/excel/ExcelEmitter.java
if(list.getChildren( ) == null)
		{
			HyperlinkDef link = parseHyperLink(list);
			engine.addData( ExcelLayoutEngine.EMPTY, 
							list.getComputedStyle( ), link );
		}	
	}
	public void startListBand( IListBandContent listBand )
	{	
		engine.addCell( 0, 1, listBand.getComputedStyle( ) );
	}
	
	public void endListBand( IListBandContent listBand )
	{	
		engine.endCell( );
	}
	
	public void endList( IListContent list )
	{		
		engine.endTable( );
	}
	public void startForeign( IForeignContent foreign )
	{
		if ( IForeignContent.HTML_TYPE.equalsIgnoreCase( foreign.getRawType( ) ) )
		{
			HTML2Content convert = new HTML2Content( foreign.getReportContent( )
					.getDesign( ).getReportDesign( ) );
			convert.html2Content( foreign );
			HyperlinkDef link = parseHyperLink(foreign);
			engine.addContainer( foreign.getComputedStyle( ), link );