in general I support Pauls idea, although I am wondering what has been happened to the first request on adding a Projection property to the Taks.
But Paul, can you also say why it is better to have properties than using the blackboard? I could imagine, that one simply knows what type of properties exist - while on the blackboard could be anything. But how do I know which properties are existent? @Larry and Andreas: Any comments from you on that? (I ask you too as you have way more programming experience than I have... i.e. I am rather part of the "weeks" group outlined in the memo thread ;o) cheers stefan Sunburned Surveyor schrieb: > Paul wrote: "I would like to extend the Task class to support > properties. Properties > can be set by plug-ins on the task." > > I wonder if we could use a Blackboard and PersistentBlackboardPlugIn > to accomplish this? > > http://jump-pilot.sourceforge.net/javadoc/openjump_javadoc/com/vividsolutions/jump/workbench/ui/plugin/PersistentBlackboardPlugIn.html > http://jump-pilot.sourceforge.net/javadoc/openjump_javadoc/com/vividsolutions/jump/util/Blackboard.html > > This would keep things a little simpler, as we'd be using classes that > are already present in OpenJUMP. > > This is just a suggestion. > > If we support Objects, how will we represent their state when we write > the data to the Task file? Will we just call toString on the object, > or will there be another method? > > The Sunburned Surveyor > > On Sat, May 24, 2008 at 8:55 AM, Paul Austin <[EMAIL PROTECTED]> wrote: >> Michael, >> >> The magic is new in JDK 1.5 generics. It's a generic method the <T> means >> that at compile time it should deduce anywhere it sees T (T can be anything >> you want) in the method based on the actual classes used. >> >> So in the below example we use T as the return type so the compiler can pick >> this up from your assignment statement Integer i = task.getProperty(...) and >> then use Integer where ever it sees T. >> >> public <T> T getProperty(QName name) { >> return (T)properties.get(name); >> } >> >> This just makes your code a lot easier to read as you don't have to cast in >> your code >> >> http://java.sun.com/j2se/1.5/pdf/generics-tutorial.pdf section 5 generic >> methods >> >> Paul >> >> >> Michael Michaud wrote: >> >> Paul Austin a écrit : >> >> >> I would like to extend the Task class to support properties. Properties >> can be set by plug-ins on the task. An example of a property would be >> the SRID for the whole task. This will allow us to support extended >> metadata on tasks without having to add new methods each time or >> subclassing. >> >> >> >> Seems to be a good idea to me. >> >> >> I propose to use QName's as the key for the keys for the properties. >> This would allow different namespaces for different applications. >> >> The change would include the following. >> >> private void Map<QName,Object> properties = new HashMap<QName,Object>(); >> >> public void setProperty(QName name, Object value) { >> properties.put(name, value); >> } >> >> /** >> * This will auto cast so you can just type things like >> * int value = getProperty(MY_KEY); >> */ >> public <T> T getProperty(QName name) { >> return (T)properties.get(name); >> } >> >> >> >> Hey, looks like magic code. >> I cannot understand how the type T can be used in an object method if it >> has not been declared in the class definition. >> Can really the jvm know how to cast properties.get(KEY) while the object >> associated with this key can be any Object value? >> >> Michaël >> >> >> public Map<QName,Object> getProperties() { >> } >> >> We'd also need to have it setup so this would be saved to the project file. >> >> Any suggestions/comments? >> >> Paul >> >> ------------------------------------------------------------------------- >> 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/ >> _______________________________________________ >> 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: Microsoft >> Defy all challenges. Microsoft(R) Visual Studio 2008. >> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >> _______________________________________________ >> 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: Microsoft >> Defy all challenges. Microsoft(R) Visual Studio 2008. >> http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ >> _______________________________________________ >> 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: Microsoft > Defy all challenges. Microsoft(R) Visual Studio 2008. > http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ > _______________________________________________ > 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: Microsoft Defy all challenges. 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