Bug 188843 NPE throws out when preview sample report in xls[1203]
engine/org.eclipse.birt.report.engine.emitter.prototype.excel/src/org/eclipse/birt/report/engine/emitter/excel/StyleEngine.java
StyleBuilder.applyBottomBorder( entry, ( (Data) dataMap.get( i
					+ col, cp ) ).style );
		}
		
		style2top.remove( entry );
	}
	public Span getContainerSpan( )
	{
		return (Span) spans.peek( );
	}
	public StyleEntry getStyle( IStyle style, Span span )
	{
		
		return initStyle( style, span );
	}
	public int getStyleID( StyleEntry entry )
	{		
		if ( style2id.get( entry ) != null )
		{
			return ( (Integer) style2id.get( entry ) ).intValue( );
		}
		else
		{
			int styleId = ID;
			style2id.put( entry, new Integer( styleId ) );
			ID++;
			return styleId;
		}
	}