Bug 203204 [Regression] Error occors when preview the attached report design as XLS [1203]
engine/org.eclipse.birt.report.engine.emitter.prototype.excel/src/org/eclipse/birt/report/engine/emitter/excel/ExcelWriter.java
if ( result == null )
			{
				return s;
			}
			return result.toString( );
		}
	}
	protected static Logger logger = Logger.getLogger( ExcelWriter.class
			.getName( ) );
	public ExcelWriter( OutputStream out )
	{
		this( out, "UTF-8" );
	}
	public ExcelWriter( OutputStream out, String encoding )
	{
		writer.open( out, encoding );
	}
	
	
	
	public void writeText( Data d )
	{
		writer.openTag( "Data" );
		if ( d.getDatatype( ).equals( Data.NUMBER ) )
		{
			writer.attribute( "ss:Type", "Number" );
		}
		else if ( d.getDatatype( ).equals( Data.DATE ) )
		{
			writer.attribute( "ss:Type", "DateTime" );