Bug 201017 TopN, TopPercent, BottomPercent filters will lead NPE when the values contains NULL[07]
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/script/NEvaluator.java
{
			
			
			Object n_object = null;
			try
			{
				n_object = ExprEvaluateUtil.evaluateRawExpression2( n_expr, scope );
			}
			catch ( BirtException e1 )
			{
				throw DataException.wrap( e1 );
			}
			double n_value = -1;
			try
			{
				n_value = DataTypeUtil.toDouble( n_object ).doubleValue();
			}
			catch ( BirtException e )
			{
				
				throw new DataException(ResourceConstants.INVALID_TOP_BOTTOM_ARGUMENT, e);
			}
			
			
			if( n_percent )
			{
				if( n_value < 0 || n_value > 100)
					throw new DataException(ResourceConstants.INVALID_TOP_BOTTOM_PERCENT_ARGUMENT);
				N = (int)Math.round( n_value / 100 * filterPassController.getRowCount() );
			}