Bug 201017 TopN, TopPercent, BottomPercent filters will lead NPE when the values contains NULL[07]
data/org.eclipse.birt.data.tests/test/org/eclipse/birt/data/engine/aggregation/TotalTest.java
ac.start();
        for(int i=0; i<doubleArray3.length; i++)
        {
            ac.onRow(new Object[]{doubleArray3[i]});
        }
        ac.finish();
        
        ac.start();
        for(int i=0; i<doubleArray3.length; i++)
        {
            ac.onRow(new Object[]{doubleArray3[i]});
        	assertEquals(doubleArray3PercentSum[i], ac.getValue().equals( "" )?null:new Integer((int)(new Double(ac.getValue().toString()).doubleValue( )*1000)));
        }
        ac.finish();
        
        ac.start( );
		for ( int i = 0; i < str2.length; i++ )
		{
			try
			{
				ac.onRow( new Object[]{
					str2[i]
				} );
				fail( );
			}
			catch ( DataException e )
			{
			}
		}
		ac.finish( );