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
else 
			{
				Object result;
				
				if( value.equals(nullValueReplacer) )
					result = this.doCompare( null, valueList.get( i ));
				else if ( valueList.get( i ).equals(nullValueReplacer))
					result = this.doCompare( value, null );
				else
					result = this.doCompare( value, valueList.get( i ) );
				
				try
				{
					
					if ( DataTypeUtil.toBoolean( result ).booleanValue( ) == true )
					{
						for( int j = activeCount - 1; j > i; j--)
						{
							valueList.set( j, valueList.get( j - 1 ) );
							rowIdList.set( j, rowIdList.get( j - 1 ) );
						}
						valueList.set( i, value );
						rowIdList.set( i,
								new Integer( firstPassRowNumberCounter ) );
						break;
					}
				}
				catch ( BirtException e )
				{
					throw DataException.wrap(e);