Bug 204090 render a small rptdocument to PDF will be OutofMemory
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/layout/pdf/util/TableProcessor.java
{
		CellContent cell;
		InternalCellContent( CellContent cell )
		{
			this.cell = cell;
		}
		public boolean isEmpty( )
		{
			return cell != null;
		}
		public void reset( )
		{
		}
	}
}