Landon, Have you looked into the StAX API for XML pull-parsing? I'm using it to parse KML, and it makes for fairly easy parser implementation (e.g. recursive descent, which is the simplest for us humans to code up).
http://en.wikipedia.org/wiki/StAX http://woodstox.codehaus.org/ Sunburned Surveyor wrote: > I've looked at this problem, and I think it would be possible to write > a fairly simple GML parser that didn't need a schema, as long as the > GML file only contained features of one type. It would be possible to > write the same type of parser for GML files that contain features of > different types, but it would be more work. I would like to start with > the simpler use case first. > > I wrote some simple code to replace JDOM, and a GML 2 parser would be > a good test of it. Perhaps I could rearrange some priorities and get > this busted out in the next couple of weeks. > > Landon > > On Wed, May 20, 2009 at 11:14 AM, Martin Davis <mbda...@refractions.net> > wrote: > >> Has anyone looked at the GeoTools GML reader, to see if it's a >> reasonable thing to include with OJ? >> >> Writing GML readers is not a trivial task - that was why we went with >> the template idea (so as to push the complexity back onto the human). >> There might be some simpler approaches that could be looked at, though - >> such as pre-scanning the GML file to try and deduce the Feature tag, >> attribute tags & types, and the geometry tag. It would be an >> interesting project... I'd be surprised if someone hasn't already >> worked on this. OGR is another possible model to follow - not sure what >> they do for parsing GML. The thing that seems really difficult to do is >> to analyze the schema and use that to direct the parsing - that is >> basically equivalent to writing a parser generator, which is a >> non-trivial task. >> >> Sunburned Surveyor wrote: >> >>> I understand the concern about adding a big library to OpenJUMP. I do >>> plan on adding CRS capability to OpenJUMP (sometime this year?) and I >>> have already started putting together the dependencies for the CRS >>> code. >>> >>> I wouldn't be against just splitting out the packages we need to use >>> from the bigger deegree Project libraries, as long as this doesn't get >>> ridiculous. I suppose we can see how this goes with the CRS code. >>> >>> I don't know if it is worth integrating the degree libs for the GML >>> parser. I think we can probably whip up our own lightweight solution >>> to this problem. >>> >>> The Sunburned Surveyor >>> >>> On Wed, May 20, 2009 at 1:14 AM, Andreas Schmitz <schm...@lat-lon.de> wrote: >>> >>> >>>> Stefan Steiniger wrote: >>>> >>>> >>>>> Michaël Michaud wrote: >>>>> >>>>> >>>> Hi, >>>> >>>> >>>> >>>>>> Here are my thoughts about the question : >>>>>> - Andreas is one of the main contributors of the project, so his own >>>>>> advice about what is good for OpenJUMP is much welcome >>>>>> >>>>>> >>>> thanks, although I don't feel like I've been contributing much lately... >>>> >>>> >>>> >>>>>> - I wouldn't like to see big libraries added to openjump just to be able >>>>>> to use a few classes of those libraries, but small packages to add >>>>>> capabities to OJ are OK >>>>>> >>>>>> >>>> Yes, that's why I'm also hesitating a little (see below). >>>> >>>> >>>> >>>>>> - To answer more precisely, It would be interesting to know >>>>>> if deegree code should be included as a whole or on a per package >>>>>> basis >>>>>> what would be the size and the potential of each package for OpenJUMP >>>>>> what would be the redundances with existing OJ code (which may need >>>>>> to clean some parts of existing code...) >>>>>> >>>>>> >>>> I think that would be fairly difficult and not worth it. Once the GML >>>> parsing is >>>> used, you use a major part of deegree (feature model, CRS, GML model, >>>> geometry >>>> model etc.), so that copying over only required packages makes it virtually >>>> impossible to keep in sync with the code base. >>>> >>>> >>>> >>>>> Yep, Michael summarizes it very well. >>>>> I'm also a hesitating to add a big lib of which we may use only a few >>>>> things. Although deegree may offer a lot of functionality for the future >>>>> (GML and CRS wise and the extended feature model?). >>>>> >>>>> >>>> I have to agree with you here as well. If we'd have some funding to >>>> integrate >>>> reprojection based on deegree in OpenJUMP, I'd certainly opt for 'yes'. If >>>> we >>>> 'only' want GML, I'd opt for 'maybe yes'. >>>> >>>> There are certainly a LOT of ideas where deegree code could be used to >>>> improve >>>> OpenJUMP (think WCS client, access to all data sources raster/vector that >>>> deegree can use), but any of them would require some work to implement and >>>> make >>>> stable. >>>> >>>> >>>> >>>>> Does it actually make a difference in terms of memory footprint, i.e. >>>>> are all deegree classes loaded? >>>>> >>>>> >>>> Only classes that are actually used are loaded. If the user does not use >>>> any >>>> functionality that uses deegree, no deegree class is loaded at all. >>>> >>>> Best regards, Andreas >>>> -- >>>> l a t / l o n GmbH >>>> Aennchenstrasse 19 53177 Bonn, Germany >>>> phone ++49 +228 18496-0 fax ++49 +228 1849629 >>>> http://www.lat-lon.de http://www.deegree.org >>>> ------------------------------------------------------- >>>> OpenStreetMap im Rheinland - May 26th >>>> deegree day 2009 - May 27th >>>> http://deegreeday.deegree.org >>>> >>>> -----BEGIN PGP SIGNATURE----- >>>> Version: GnuPG v1.4.9 (GNU/Linux) >>>> >>>> iEYEARECAAYFAkoTu9gACgkQ737OVr+Ru7rdXgCfal7ZpzSc/Jqo6bG3vL4UsGTU >>>> AUkAn2ry5cfIpNOfBzJ7T8aFhaOsl0aC >>>> =5U1K >>>> -----END PGP SIGNATURE----- >>>> >>>> ------------------------------------------------------------------------------ >>>> Crystal Reports - New Free Runtime and 30 Day Trial >>>> Check out the new simplified licensing option that enables >>>> unlimited royalty-free distribution of the report engine >>>> for externally facing server and web deployment. >>>> http://p.sf.net/sfu/businessobjects >>>> _______________________________________________ >>>> Jump-pilot-devel mailing list >>>> Jump-pilot-devel@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel >>>> >>>> >>>> >>>> >>> ------------------------------------------------------------------------------ >>> Crystal Reports - New Free Runtime and 30 Day Trial >>> Check out the new simplified licensing option that enables >>> unlimited royalty-free distribution of the report engine >>> for externally facing server and web deployment. >>> http://p.sf.net/sfu/businessobjects >>> _______________________________________________ >>> 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 >> >> >> ------------------------------------------------------------------------------ >> Crystal Reports - New Free Runtime and 30 Day Trial >> Check out the new simplified licensing option that enables >> unlimited royalty-free distribution of the report engine >> for externally facing server and web deployment. >> http://p.sf.net/sfu/businessobjects >> _______________________________________________ >> Jump-pilot-devel mailing list >> Jump-pilot-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel >> >> > > ------------------------------------------------------------------------------ > Crystal Reports - New Free Runtime and 30 Day Trial > Check out the new simplified licensing option that enables > unlimited royalty-free distribution of the report engine > for externally facing server and web deployment. > http://p.sf.net/sfu/businessobjects > _______________________________________________ > 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 ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Jump-pilot-devel mailing list Jump-pilot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/jump-pilot-devel
