Menu
▾
▴
Re: [Bodington-developers] Plugin interface
|
From: Colin T. <col...@ou...> - 2006-03-23 09:59:56
|
Alistair Young wrote: > either I'm not getting messages again or it's all gone quiet. ;-) > We'd like > to put org.bodington.plugin and some interfaces in for 2.8 so we can > factor out our My Modules but still leave a hook in Facility. > > This ok with bod.org? I think it's a bit to soon to add it to 2.8. It's a new approach and I think it would be sensible to give it more time -- once something's in a release version it's messy to change. I realise that doesn't help with your problem. I think MyModules could be useful to other users, so it would be good if it was available... Colin > On 22 Mar 2006, at 14:32, Alistair Young wrote: > >> I'm happy to pursue this Adam, if we can agree on how to implement them >> for v1. Lots to think about. We have a concrete use case for a plugin >> though, which means minimal merging of Facility. >> >> The real quesion is whether it's good or bad to let templates call any >> class they want. That would free up plugin developers from using >> Facility. >> >> -- >> Alistair Young >> Senior Software Engineer >> UHI@Sabhal Mòr Ostaig >> Isle of Skye >> Scotland >> >>> Plugins are something that Boding desparately needs, perhaps we should >>> dedicate >>> some time to work with Al after our new WebLearn release? >>> >>> adam >>> >>> In message <7A5...@sm...> >>> bod...@li... writes: >>> >>>> damn list - I didn't get the original of this message and it came >>>> from me! >>>> >>>>> Can you create a subclass of Facility? >>>> >>>> I think Facility is a lost cause. We'll wait for Tetra! >>>> >>>> Thinking about maybe specific plugins - ScreenPlugin - writes to >>>> screen, DBPlugin - does stuff with the DB. It's just a way to >>>> refactor code out of Facility into small packages of functionality >>>> that can better be merged etc. Dare I even say, configured at run >>>> time too, ala struts/spring (I see cabbages heading my way). >>>> >>>> The basic idea is to have, say, a plugins package in bod: >>>> >>>> org.bodington.plugin >>>> >>>> and have specific interfaces in there: >>>> >>>> ScreenPlugin >>>> DBPlugin >>>> >>>> public interface ScreenPlugin { >>>> public void run(Request req, PrintWriter writer) throws UP; >>>> } >>>> >>>> not saying that's what they should be called, just to illustrate. >>>> >>>> Template then calls Facility.writeModuleLinks >>>> >>>> Facility.writeModuleLinks (Request req, PrintWriter writer) { >>>> ScreenPlugin minerva = (ScreenPlugin)Class.forName >>>> ("org.bodington.contrib.Minerva"); >>>> minerva.run(req, writer): >>>> } >>>> >>>> maybe as you say, use a subclass of Facility as a facade for the >>>> plugin. >>>> >>>> public class MinervaHelper extends Facility { >>>> writeModuleLinks( ... ) { >>>> ScreenPlugin ... >>>> } >>>> } >>>> >>>> so a template calls a plugin's facade - MinervaHelper - class instead >>>> of Facility >>>> >>>> Can a template call methods in more than one class though? i.e. it >>>> might need functionality that's in more than one plugin. >>>> >>>> Alistair >>>> >>>> >>>> >>>> On 22 Mar 2006, at 10:17, Matthew Buckett wrote: >>>> >>>>> Alistair Young wrote: >>>>> >>>>>> Bodders, I've been delurked, damn, to ask opinions. >>>>>> >>>>>> We have a requirement for My Modules, which is specific to us so >>>>>> we don't >>>>>> want to pollute Facility. However, a template must call facility >>>>>> to get it >>>>>> to write stuff to the screen. >>>>> >>>>> >>>>> Can you create a subclass of Facility? >>>>> >>>>>> The writing is delegated to another class which is currently in >>>>>> org.bodington.contrib on our HEAD but Facility still needs to know >>>>>> about >>>>>> the class to delegate to it - it has to cast to call methods etc, >>>>>> so it >>>>>> has to know about the specific class. >>>>> >>>>> >>>>> At least the delegate methods should be small. This is how I pulled >>>>> the >>>>> StyleSheet code out on WebLearn HEAD. There is still the problem that >>>>> Facility ends up with 100s of method calls. >>>>> >>>>>> A better way would be to define, e.g. >>>>>> >>>>>> package org.bodington.contrib; >>>>>> >>>>>> public interface Plugin { >>>>>> public void run(Request req, PrintWriter writer) throws >>>>>> SomeOrribleException; >>>>>> } >>>>>> >>>>>> then our class could implement Plugin and Facility would only have >>>>>> to load >>>>>> it via Class.forName as a Plugin and call it's run method. >>>>> >>>>> >>>>> Can you explain the call graph a little more. >>>>> >>>>>> It reduces the code in Facility and brings a sort of IOC/ dependancy >>>>>> injection to Facility. >>>>>> >>>>>> What would be even better though is allowing templates to call >>>>>> whatever >>>>>> class they wanted and not just Facility or a subclass thereof. >>>>> >>>>> >>>>> I added support for making static calls from template but I don't >>>>> think >>>>> this is a good move as then it becomes move difficult to refactor >>>>> code >>>>> as you can't be sure without recompiling the templates if a method is >>>>> actually used. At the moment you only have todo this checking when >>>>> working with public methods in Facility. It also means that the >>>>> idea of >>>>> linking a template with a Facility in a configuration file breaks >>>>> down. >>>>> >>>>> >>>>> -- >>>>> -- Matthew Buckett, VLE Developer >>>>> -- Learning Technologies Group, Oxford University Computing Services >>>>> -- Tel: +44 (0)1865 283660 http://www.oucs.ox.ac.uk/ltg/ >>>>> >>>>> >>>>> ------------------------------------------------------- >>>>> This SF.Net email is sponsored by xPML, a groundbreaking scripting >>>>> language >>>>> that extends applications into web and mobile media. Attend the >>>>> live webcast >>>>> and join the prime developer group breaking into this new coding >>>>> territory! >>>>> http://sel.as-us.falkag.net/sel? >>>>> cmd=lnk&kid=110944&bid=241720&dat=121642 >>>>> _______________________________________________ >>>>> Bodington-developers mailing list >>>>> Bod...@li... >>>>> https://lists.sourceforge.net/lists/listinfo/bodington-developers >>>> >>>> >>>> >>>> >>>> ------------------------------------------------------- >>>> This SF.Net email is sponsored by xPML, a groundbreaking scripting >>>> language >>>> that extends applications into web and mobile media. Attend the live >>>> webcast >>>> and join the prime developer group breaking into this new coding >>>> territory! >>>> http://sel.as-us.falkag.net/sel? >>>> cmd=lnk&kid=110944&bid=241720&dat=121642 >>>> _______________________________________________ >>>> Bodington-developers mailing list >>>> Bod...@li... >>>> https://lists.sourceforge.net/lists/listinfo/bodington-developers >>>> >>> >>> -- >>> -- >>> Dr AC Marshall (Bodington developer) OUCS, 13, Banbury Rd. Oxford. >>> OX2 6NN >>> Cheese of the month: Smoked Wensleydale >>> >>> >>> ------------------------------------------------------- >>> This SF.Net email is sponsored by xPML, a groundbreaking scripting >>> language >>> that extends applications into web and mobile media. Attend the live >>> webcast >>> and join the prime developer group breaking into this new coding >>> territory! >>> http://sel.as-us.falkag.net/sel?cmd=lnk&kid0944&bid$1720&dat1642 >>> _______________________________________________ >>> Bodington-developers mailing list >>> Bod...@li... >>> https://lists.sourceforge.net/lists/listinfo/bodington-developers >>> >> >> >> >> ------------------------------------------------------- >> This SF.Net email is sponsored by xPML, a groundbreaking scripting >> language >> that extends applications into web and mobile media. Attend the live >> webcast >> and join the prime developer group breaking into this new coding >> territory! >> http://sel.as-us.falkag.net/sel?cmd=lnk&kid0944&bid$1720&dat1642 >> _______________________________________________ >> Bodington-developers mailing list >> Bod...@li... >> https://lists.sourceforge.net/lists/listinfo/bodington-developers > > > > > ------------------------------------------------------- > This SF.Net email is sponsored by xPML, a groundbreaking scripting language > that extends applications into web and mobile media. Attend the live > webcast > and join the prime developer group breaking into this new coding territory! > http://sel.as-us.falkag.net/sel?cmd=k&kid0944&bid$1720&dat1642 > _______________________________________________ > Bodington-developers mailing list > Bod...@li... > https://lists.sourceforge.net/lists/listinfo/bodington-developers > > -- ____________________________________ Colin Tatham VLE Team Oxford University Computing Services http://www.oucs.ox.ac.uk/ltg/vle/ http://bodington.org |
