I couldn't help myself, and I looked at the code over the code for GMLReader over my lunch break. Larry is correct, the code is pretty gnarly. I believe the use of a state machine is caused by the fact that a SAX parser pushes xml events to the class. This problem could be avoided if you used something like JDOM or an XML pull parser.
The good news is I can fix the code to read linear rings. The bad news is it would take me probably 10 to 20 hours. I'd have to really dig into the class so I could understand what was going on. I think the code complex enough that if you just tried to add a few lines of code you'd dork something up. Here are the options, in my opinion: [1] Leave things as they are. The GMLReader class won't read LinearRings. Close the bug report. [2] Add support for reading linear rings to the exisitng GMLReader class. If I did this work I would probably reorganize all the stinking if statements and other conditional tests into some private methods so the class was easier to read and maintain. I'd also want to document the way the class works for the next fool that trys to fix a bug with GML import. [3] Write a new GMLReader class that uses an XML pull-parser. This would greatly simplify the class and make it easier to improve/maintain GML import. I think this would take about the same amount of time as understanding the existing class would take. I also think it would be possible to remove the need for an input template by automatically detecting the data type of attribute values. If I went this route I could allow the user to override this automatic data type detection with a simple properties file. I think removing the need for an input template would make GML 2.0 import a lot easier for the user. I'm looking for advice on the best way to proceed. Which option would benefit the community the most? If no one really cares about GML 2.0 (I don't know how many of us are using it) then I will make my own decision and move forward. The Sunburned Surveyor On Thu, Nov 20, 2008 at 11:36 AM, Sunburned Surveyor <[EMAIL PROTECTED]> wrote: > Thanks for the files Larry. There are some comments on the state > machine in the Javadoc for the GMLReader class, but no diagram. I'm > sure you looked at this when you were attempting to make your KML > Reader. > > I'll take a peek at the code today after work I hope. > > SS > > On Thu, Nov 20, 2008 at 10:57 AM, Larry Becker <[EMAIL PROTECTED]> wrote: >> You can create LinearRings by using the Geometry Converter plugin. OJ >> supports writing LinearRings to GML, but not reading them. See the attached >> files. I have looked at the GMLReader code when morphing it into the KML >> Reader. It isn't going to be easy to modify, and has so far resisted all my >> attempts at making a KML Reader that supports Attributes. The code is a >> very complex state machine. What would help is the state diagram that was >> used to create the original code. >> >> regards, >> Larry >> >> On Thu, Nov 20, 2008 at 12:07 PM, Sunburned Surveyor >> <[EMAIL PROTECTED]> wrote: >>> >>> Martin, >>> >>> Thanks for your valuable input. I will look at the code, but I suspect >>> the best thing to do is to load LinearRings as LineStrings and ecplain >>> this behavior in the Javadoc. >>> >>> I'll report back to the list when I have a patch. >>> >>> SS >>> >>> On Thu, Nov 20, 2008 at 10:00 AM, Martin Davis <[EMAIL PROTECTED]> >>> wrote: >>> > Well, it's a valid geometry type in JTS, so it should work in OJ. There >>> > may be limitations in how it can be manipulated, however - e.g. I >>> > suspect that it can't be edited (or at least that if it is it will >>> > revert to a plain ol LineString). >>> > >>> > If this is a concern, another option is to load LinearRings as >>> > LineStrings. They should NOT be loaded as Polygons - LinearRings are >>> > not areas. >>> > >>> > Sunburned Surveyor wrote: >>> >> Martin, >>> >> >>> >> Is that a valid feature geometry type in OpenJUMP? I didn't know that >>> >> it was. If it is, then this probably is a bug that needs to get fixed. >>> >> >>> >> SS >>> >> >>> >> On Thu, Nov 20, 2008 at 9:06 AM, Martin Davis <[EMAIL PROTECTED]> >>> >> wrote: >>> >> >>> >>> Why not read the GML LinearRing into a JTS LinearRing? >>> >>> >>> >>> Sunburned Surveyor wrote: >>> >>> >>> >>>> Well, it seems from a "robustness" perspective that it would be good >>> >>>> to read in linear rings, even if they are always represented >>> >>>> internally and exported as polygons. >>> >>>> >>> >>>> I will wait for other programmers to comment on what they think the >>> >>>> best course is, then I will implement the needed changes. >>> >>>> >>> >>>> SS >>> >>>> >>> >>>> On Thu, Nov 20, 2008 at 8:38 AM, Andreas Schmitz <[EMAIL PROTECTED]> >>> >>>> wrote: >>> >>>> >>> >>>> >>> >>>>> Sunburned Surveyor wrote: >>> >>>>> >>> >>>>> Hi, >>> >>>>> >>> >>>>> >>> >>>>> >>> >>>>>> I'm working on one of the OJ 1.2 bugs I selected for squishing and >>> >>>>>> I >>> >>>>>> had a quick question. >>> >>>>>> >>> >>>>>> Is the GML reader in OpenJUMP supposed to read features represented >>> >>>>>> by >>> >>>>>> a LinearRing? I thought a LinearRing was only used as an exterior >>> >>>>>> or >>> >>>>>> interior boundary of a polygon. A user filed a bug report because a >>> >>>>>> feature geometry wasn't created from a LinearRing using JUMP's >>> >>>>>> GMLReader. But I'm thikning that this isn't a bug, but an improper >>> >>>>>> understanding of how feature geometries are represented in GML. A >>> >>>>>> feature should be represented by a polygon, not a linear ring. >>> >>>>>> >>> >>>>>> If GMLReader is supposed to construct a feature goemetry (polygon?) >>> >>>>>> from a linear ring, then I'll fix the bug. If GMLReader is not >>> >>>>>> supposed to do this, because it isn't the proper way to represent a >>> >>>>>> feature, then I will close the bug. >>> >>>>>> >>> >>>>>> >>> >>>>> I think in GML2 this is allowed: >>> >>>>> >>> >>>>> http://schemas.opengis.net/gml/2.1.2/geometry.xsd >>> >>>>> >>> >>>>> One can always wonder why anyone would want it, but some people >>> >>>>> apparently have >>> >>>>> use cases for everything... The problem that is inherent here is, if >>> >>>>> you read >>> >>>>> the linear ring in as a polygon, what happens when exporting as GML >>> >>>>> again? Will >>> >>>>> it be exported as polygon or as linear ring? Is every linear ring >>> >>>>> also a >>> >>>>> polygon? I suppose not, as there are almost no restrictions on the >>> >>>>> form of a >>> >>>>> linear ring, but many (such as orientation of the rings, self >>> >>>>> intersections >>> >>>>> etc.) on polygons. >>> >>>>> >>> >>>>> I'm unsure on how to solve this problem though, the better you want >>> >>>>> to solve it, >>> >>>>> the more work it is obviously. >>> >>>>> >>> >>>>> Best regards, Andreas >>> >>>>> -- >>> >>>>> l a t / l o n GmbH >>> >>>>> Aennchenstrasse 19 53177 Bonn, Germany >>> >>>>> phone ++49 +228 18496-12 fax ++49 +228 1849629 >>> >>>>> http://www.lat-lon.de http://www.deegree.org >>> >>>>> >>> >>>>> -----BEGIN PGP SIGNATURE----- >>> >>>>> Version: GnuPG v1.4.9 (GNU/Linux) >>> >>>>> >>> >>>>> iEYEARECAAYFAkklkpUACgkQ737OVr+Ru7pgtACg5bMBBMLlo3wNsiXw7D+BB0tz >>> >>>>> OG8AoJc+QpDAnPZ2NTA+K//fxBcsCHI7 >>> >>>>> =9hXg >>> >>>>> -----END PGP SIGNATURE----- >>> >>>>> >>> >>>>> >>> >>>>> ------------------------------------------------------------------------- >>> >>>>> This 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Jump-pilot-devel@lists.sourceforge.net >>> >>> https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel >>> >>> >>> >>> >>> >> >>> >> >>> >> ------------------------------------------------------------------------- >>> >> This SF.Net email is sponsored by the Moblin Your Move Developer's >>> >> challenge >>> >> Build the coolest Linux based applications with Moblin SDK & win great >>> >> prizes >>> >> Grand prize is a trip for two to an Open Source event anywhere in the >>> >> world >>> >> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>> >> _______________________________________________ >>> >> Jump-pilot-devel mailing list >>> >> Jump-pilot-devel@lists.sourceforge.net >>> >> https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel >>> >> >>> >> >>> > >>> > -- >>> > Martin Davis >>> > Senior Technical Architect >>> > Refractions Research, Inc. >>> > (250) 383-3022 >>> > >>> > >>> > >>> > ------------------------------------------------------------------------- >>> > This SF.Net email is sponsored by the Moblin Your Move Developer's >>> > challenge >>> > Build the coolest Linux based applications with Moblin SDK & win great >>> > prizes >>> > Grand prize is a trip for two to an Open Source event anywhere in the >>> > world >>> > http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>> > _______________________________________________ >>> > Jump-pilot-devel mailing list >>> > Jump-pilot-devel@lists.sourceforge.net >>> > https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel >>> > >>> >>> ------------------------------------------------------------------------- >>> This SF.Net email is sponsored by the Moblin Your Move Developer's >>> challenge >>> Build the coolest Linux based applications with Moblin SDK & win great >>> prizes >>> Grand prize is a trip for two to an Open Source event anywhere in the >>> world >>> http://moblin-contest.org/redirect.php?banner_id=100&url=/ >>> _______________________________________________ >>> 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