If I remember correctly, geotools.tile was either added about mid-way through my project, or I only found about it then. By that point, I had bits of JTileCache already written, and was reluctant to switch over. In retrospect, I shouldn't have been that short-sighted.
Another reusability area is generic caching-- in an ideal world, all the Java caching libraries would provide a java.util.Map interface, and everything would be perfectly reusable. But, most of them don't offer any sort of standard interface. Plus, there is some need to have a larger cache interface for operations such as setting expire times, gathering performance statistics, and so on. This is a problem that I would like to see addressed at a larger level-- something like the Commons Logging equivalent for caching. Apache Commons contains a cache project, but it is dormant. Out of curiosity, are you looking to use the persistent HashTable for GeoWebCache? (If so, I'm not sure I that follow.) -- Chris Whitney On Mar 1, 2008, at 12:42 PM, Arne Kepp wrote: > I need to look more into this, probably after I get 0.7 out (not the > 0.7 > still advertised on the website). > > Note that, unlike JTileCache, GeoWebCache stores the tiles as > compressed > images in the format you want to return, so most of the work is > figuring > out what the correct cache key is for a given request and then how to > get that from the backend. I had to pull JAI out right before 0.6 > because I had some problems with it. But it's only three lines in the > code (slicing up tiles), and wasn't that important since it saves > milliseconds after a WMS request that typically takes several seconds > anyway. > > I wrote a few lines on how GeoWebCache (currently) works, short and > subject to change, but hopefully a starting point for further > inquiries: http://geowebcache.org/trac/wiki/developers/overview > > -Arne > > ps. If anyone knows of a good and simple persistent hashtable, > suitable > for storing PNGs and the likes to a file, please let me know :) > > > Simone Giannecchini wrote: >> Here you have a few thoughts that I have been giving to three topics >> which may be seems different but which I would like to reconcile at >> least at the tilecache level >> >> 1>geoweb cache >> 2>geotools tile >> 3>geotools internal overviews management (yeah I am talking about >> wither reusing overviews when you have them or about generating them >> on the fly using JAI and persisting them to disk when you don't have >> them) >> >> The goal in my mind would be unifying the tile cache management for >> the three different things into only one. I have done some work in >> this direction in the past but for medical imaging and for speed >> limit >> enforcement cameras (yeah, don't spread the word out there :-) ). I >> have played while at foss4g with small parts of this code and tried >> to >> integrate them in uDig and the difference in performances is pretty >> big >> >> I already talked a little bit to arne just to try and understand how >> geowebcache works (even because we plan on using it). I think it >> would >> be great to have some documentation on how geowebcache works (I don't >> know if it already exists :-) ). >> >> >> Simone. >> >> On Sat, Mar 1, 2008 at 12:41 PM, Chris Holmes >> <[EMAIL PROTECTED]> wrote: >> >>> Interesting, I didn't realize that org.geotools.tile exists. >>> >>> It might be really good to reconcile the implementation in >>> geotools with >>> what Arne's done in GeoWebCache, so we can reuse code. All our >>> work we >>> like to get in geotools if there's the potential for wider reuse, >>> but I >>> wasn't aware there was already work done on this. I'm not sure if >>> it's >>> appropriate to reuse everything, but it'd be nice to at least use >>> the >>> same code to access alternate tile servers. Also note that we've >>> got >>> 'metaTiling' code in GeoWebCache, leveraging JAI, which can make for >>> some nicer looking tiles. Arne should be able to tell you more and >>> figure out how best to collaborate. >>> >>> best regards, >>> >>> Chris >>> >>> >>> Jody Garnett wrote: >>> >>>> Sounds good, I am the module maintainer for unsupported/tile if >>>> you have >>>> any questions please ask. >>>> >>>> You should find the code base organized to allow: >>>> - alternate TileCache implementations to be substituted (although >>>> perhaps we need to make a plug-in mechanism?) >>>> - additional "tile" servers >>>> >>>> We may find it worthwhile to talk to the JAI Gurus on this list >>>> at a >>>> later stage - they could hook us up with the JAI Tile Cache etc... >>>> >>>> In the broader scheme of things we should make a specific MapLayer >>>> implementation for the MapContext data structure and allow >>>> the GeoTools renderer to make use of these services. >>>> >>>> For my part I would like to make a implementation that talks to >>>> MapGuide >>>> Open Source; so GeoServer could hang out the front end and offer >>>> a good >>>> WMS implementations on top of it. >>>> >>>> Jody >>>> >>>>> Hi everyone, >>>>> >>>>> the module org.geotools.tile currently has an implementation for >>>>> accessing the NASA World Wind server and an implementation of a >>>>> SimpleTileCache, which caches only the result of the last query. >>>>> >>>>> We would like to add support for WMS-C [1]. Server >>>>> implementations are >>>>> available from MetaCarta [2] or from GeoWebCache [3]. >>>>> >>>>> Additionally we want to create at least two tile cache >>>>> implementations >>>>> (MemoryTileCache and DiskTileCache). It should be possible to >>>>> configure >>>>> the size of the cache (number of tiles to be cached) and to plug- >>>>> in a >>>>> cache algorithm like Least Recently Used, Least Frequently Used, >>>>> or >>>>> maybe Adaptive Replacement Cache. Caches can be used in a cache >>>>> hierarchy. >>>>> >>>>> Are there currently and other activities in that area that we >>>>> should be >>>>> aware of? Are there any ideas oder suggestions from you? >>>>> >>>>> Regards, >>>>> Holger >>>>> >>>>> >>>>> [1] http://wiki.osgeo.org/wiki/WMS_Tiling_Client_Recommendation >>>>> [2] http://www.tilecache.org/ >>>>> [3] http://geowebcache.org/ >>>>> >>>>> --- >>>>> Holger Jaekel >>>>> phone: +49 (89) 121528-75 mailto:[EMAIL PROTECTED] >>>>> fax: +49 (89) 121528-79 http://www.gaf.de >>>>> GAF AG Arnulfstr. 197 80634 Muenchen Germany >>>>> >>>>> Vorstand: Dr. Peter Volk, Aufsichtsratsvorsitzender: Marcello >>>>> Maranesi >>>>> >>>>> Amtsgericht Muenchen HRB 140 509, Firmensitz: Muenchen >>>>> >>>>> >>>>> >>>>> >>>>> ------------------------------------------------------------------------- >>>>> This SF.net email is sponsored by: Microsoft >>>>> Defy all challenges. Microsoft(R) Visual Studio 2008. >>>>> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >>>>> _______________________________________________ >>>>> Geotools-devel mailing list >>>>> Geotools-devel@lists.sourceforge.net >>>>> https://lists.sourceforge.net/lists/listinfo/geotools-devel >>>>> >>>>> >>>> >>>> ------------------------------------------------------------------------- >>>> This SF.net email is sponsored by: Microsoft >>>> Defy all challenges. Microsoft(R) Visual Studio 2008. >>>> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >>>> _______________________________________________ >>>> Geotools-devel mailing list >>>> Geotools-devel@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/geotools-devel >>>> >>>> >>>> >>>> >>> ------------------------------------------------------------------------- >>> This SF.net email is sponsored by: Microsoft >>> Defy all challenges. Microsoft(R) Visual Studio 2008. >>> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >>> _______________________________________________ >>> Geotools-devel mailing list >>> Geotools-devel@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/geotools-devel >>> >>> >>> >> >> >> >> > > > ------------------------------------------------------------------------- > This SF.net email is sponsored by: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > Geowebcache-devel mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/geowebcache-devel ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. 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