Bug 123726 "Top n", "Bottom n" in highlight dialog doesn't work.
Description: "Top n", "Bottom n" in highlight dialog doesn't work. Steps to reproduce: 1. Add a highlight for a table. 2. Set highlight rule: "account_id", "top n", "3", let its font color red. 3. Preview the report, it doesn't work. Attached is design file.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/PreparedQuery.java
DataException e = new DataException(ResourceConstants.PREPARED_QUERY_CLOSED);
			logger.logp( Level.WARNING,
					PreparedQuery.class.getName( ),
					"doPrepare",
					"PreparedQuery instance is closed.",
					e );
			throw e;
		}
		
		Executor executor = newExecutor();
		
		executor.setAppContext( this.getAppContext() );
		
		
		
		logger.finer( "Start to prepare the execution." );
		executor.prepareExecution( outerResults, scope );
		logger.finer( "Finish preparing the execution." );
	    return new QueryResults( engine.getContext( ),
				getDataSourceQuery( ),
				this,
				executor );
	}
	
	/**
	 * Common code to extract the name of a column from a JS expression which is
	 * in the form of "row.col". If expression is not in expected format,
	 * returns null
	 *