Re: [Geotools-gt2-users] OGC Filter - Literal Handling

[MVermeij <maa...@gm...>]

Since I'm experiencing the same problem, I would like to know whether this
problem is actually solved in the current geotools version (I am using
version gt2-2.3.3).

If it is actually solved, how do I inform geotools about the type of the
attributes?

Regards,

Maarten Vermeij



Gabriel Rold=C3=A1n wrote:
>=20
> Hi Duncan
>=20
> yes, that's an old and well known problem.
> The good news is that we have a couple ideas and are waiting for 2.3.0 to
> get=20
> out before implementing it (http://jira.codehaus.org/browse/GEOT-602)
>=20
> So please keep in sync since we're going to fix it asap, and do not
> hesitate=20
> to talk back if you have any suggestion.
>=20
>=20
> regards,
>=20
> Gabriel
> On Thursday 14 September 2006 13:25, Duncan Clarkson wrote:
>> Hi,
>>
>> We're having a problem with the way that geotools 2.1.1+ deals with
>> parsing literal values in OGC filters.  We are providing data to users
>> via Geoserver 1.3.0 which uses the 2.1.1 version of Geotools.
>>
>> Some of the datasets we offer have a string column called 'label'
>> although the value of this field can be numeric and can contain leading
>> zeros. We need to generate EqualTo and Like filters based on these
>> fields but the problem is that they are being treated as integers by
>> geotools. Here is the code that handles this
>> (org.geotools.filter.ExpressionSAXParser):
>>
>>             } else if (curExprssn instanceof LiteralExpression) {
>>                 // This is a relatively loose assignment routine, which
>> uses //  the fact that the three allowed literal types have a strict
>>                 //  instatiation hierarchy (ie. double can be an int can
>> be a
>>                 //  string, but not the other way around).
>>                 // A better routine would consider the use of this
>> expression
>>                 //  (ie. will it be compared to a double or searched wit=
h
>> a
>>                 //  like filter?)
>>                 //HACK: This should also not use exception catching, it'=
s
>>                 //expensive and bad code practice.
>>                 try {
>>                     Object temp =3D new Integer(message);
>>                     ((LiteralExpression) curExprssn).setLiteral(temp);
>>                     currentState =3D "complete";
>>                 } catch (NumberFormatException nfe1) {
>>                     try {
>>                         Object temp =3D new Double(message);
>>                         ((LiteralExpression)
>> curExprssn).setLiteral(temp);
>>                         currentState =3D "complete";
>>                     } catch (NumberFormatException nfe2) {
>>                         Object temp =3D message;
>>                         ((LiteralExpression)
>> curExprssn).setLiteral(temp);
>>                         currentState =3D "complete";
>>                     }
>>                 }
>>             }
>>
>> So if the literal can be converted to a number it will be, leading zeros
>> will be lost. This of course means that the SQL generated by Geoserver
>> to extract the features will return no data as '007' !=3D 7.
>>
>> We were thinking that a better way to handle this would be not to try
>> and convert a literal unless it is required by a calculation. Any ideas
>> or plans for what to do about this?
>>
>> Duncan
>>
>> PS. For completeness sake here is the output I have from Geoserver:
>>
>> 176638862 [FINER] org.geotools.filter.ExpressionSAXParser - incoming
>> type: Literal
>> 176638862 [FINER] org.geotools.filter.ExpressionSAXParser - declared
>> type: PropertyName
>> 176638862 [FINER] org.geotools.filter.ExpressionSAXParser - current
>> state: complete
>> 176638863 [FINER] org.geotools.filter.ExpressionSAXParser - is literal
>> expression
>> 176638863 [FINER] GMLFilterDocument - RETURN
>> 176638864 [FINER] GMLFilterDocument - ENTRY [C@ef1df6 77 3
>> 176638864 [FINER] org.geotools.filter.ExpressionSAXParser - incoming
>> message: 007
>> 176638864 [FINER] org.geotools.filter.ExpressionSAXParser - should read
>> chars: true
>> 176638865 [FINER] GMLFilterDocument - RETURN
>> 176638865 [FINER] GMLFilterDocument - ENTRY http://www.opengis.net/ogc
>> Literal ogc:Literal
>> 176638865 [FINER] org.geotools.filter.FilterFilter - found start
>> element: Literal
>> 176638865 [FINER] AbstractFilter - ENTRY 109
>> 176638865 [FINER] org.geotools.filter.FilterFilter - found an expression
>> filter end
>> 176638866 [FINER] org.geotools.filter.ExpressionSAXParser - declared
>> type: Literal
>> 176638866 [FINER] org.geotools.filter.ExpressionSAXParser - end message:
>> Literal
>> 176638867 [FINER] org.geotools.filter.ExpressionSAXParser - current
>> state: complete
>> 176638867 [FINER] org.geotools.filter.FilterFilter - expression factory
>> is ready
>> 176638868 [FINER] org.geotools.filter.ExpressionSAXParser - about to
>> create expression: 7
>> 176638868 [FINER] org.geotools.filter.FilterSAXParser - current state
>> (end): complete
>> 176638869 [FINER] GMLFilterDocument - RETURN
>> 176638869 [FINER] GMLFilterDocument - ENTRY http://www.opengis.net/ogc
>> PropertyIsEqualTo ogc:PropertyIsEqualTo
>> 176638869 [FINER] org.geotools.filter.FilterFilter - found start
>> element: PropertyIsEqualTo
>> 176638869 [FINER] AbstractFilter - ENTRY 14
>> 176638870 [FINER] org.geotools.filter.FilterSAXParser - complete called,
>> state =3D complete
>> 176638870 [FINER] org.geotools.filter.LogicSAXParser - added a filter: [
>> label =3D 7 ]
>> 176638870 [FINER] org.geotools.filter.LogicSAXParser - added to sub
>> filters: [ label =3D 7 ]
>>
>> ------------------------------------------------------------------------=
-
>> Using Tomcat but need to do more? Need to support web services, security=
?
>> Get stuff done quickly with pre-integrated technology to make your job
>> easier Download IBM WebSphere Application Server v.1.0.1 based on Apache
>> Geronimo
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=3D121642
>> _______________________________________________
>> Geotools-gt2-users mailing list
>> Geo...@li...
>> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
>=20
> --=20
> Gabriel Rold=C3=A1n (gr...@ax...)
> Axios Engineering (http://www.axios.es)
> Tel. +34 944 41 63 84
> Fax. +34 944 41 64 90
>=20
> -------------------------------------------------------------------------
> Using Tomcat but need to do more? Need to support web services, security?
> Get stuff done quickly with pre-integrated technology to make your job
> easier
> Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronim=
o
> http://sel.as-us.falkag.net/sel?cmd=3Dlnk&kid=3D120709&bid=3D263057&dat=
=3D121642
> _______________________________________________
> Geotools-gt2-users mailing list
> Geo...@li...
> https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
>=20
>=20

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