Re: More questions about generics

Hi,

I'm failing to see the best way to organize a couple of classes and
containers for them. Maybe I'm stubbornly trying to base it in
generics and I should just use a Factory pattern, I'm not sure.

I have a base "element" class (GlossaryEntry) like this:

public class GlossaryEntry {
    private String value;
    ...
}

and two classes extending it, GlossaryTerm and GlossaryTranslation:

public class GlossaryTerm extends GlossaryEntry {
    private List l;
    ...
}

public class GlossaryTranslation extends GlossaryEntry {
    private String l10nCode;
    ...
}

Now I want to have a base container for GlossaryEntry, with
corresponding extended containers for the base classes. Something like
this:

public class GlossaryEntries {
    private final List<GlossaryEntry> geList;

    // Common methods to add, delete, and retrieve elements, which
    // will be useful for both GlossaryTerm and GlossaryTranslation
    // lists
}

public class GlossaryTerms extends GlossaryEntries {
    // Specific methods useful just for GlossaryTerm lists
}

public class GlossaryTranslations extends GlossaryEntries {
    // Specific methods useful just for GlossaryTranslations lists
}

However, I'd like to make sure that GlossaryTerms only holds
GlossaryTerm elements, and do the same check with
GlossaryTranslations. So, I redefine GlossaryEntries like this:

public class GlossaryEntries<T extends GlossaryEntry> {
    private final List<T> geList;
    ...
}

but I can't see how to tell in GlossaryTerms definition that "T" must
be only "GlossaryTerm". Is there a simple way to do it "in generic
syntax"?

The other option, I guess, would be to write a Factory so I could
request a GlossaryEntries object for terms (in which case I would
return a GlosaryTerms<GlossaryTerm>), translations
(GlossaryTranslations<GlossaryTranslation>) or base (a generic
GlossaryEntries<GlossaryEntry>). Is this a sensible approach?

TIA