--- Hernan Silberman <[EMAIL PROTECTED]> wrote:
>
> > --- Hernan Silberman <[EMAIL PROTECTED]> wrote:
> > >
> > > Hello,
> > >
> > > I'm working on an application that uses "Named Queries" much like
> the
> > > DBUtils QueryLoader class reads in from a Java properties file. The
> > > queries in
> > > my application are stored in a relational database on the server
> side
> > > and I was
> > > hoping I could extend QueryLoader so it fetched the NAME/SQL pairs
> in an
> > >
> > > application-specific way, something like this:
> > >
> > > public synchronized Map load(DataSource aDS) throws IOException;
> > > public synchronized void unload(DataSource aDS);
> > >
> > > I'm new to DBUtils, and figured I'd ask before trying to extend this
> > > class in my
> > > code to accomodate something like the two methods above. Is this a
> sane
> > > thing
> > > to do? I won't get exactly what I want by extending this class,
> because
> > > I don't
> > > need the properties file versions of load and unload. Should I just
> > > create an
> > > alternate app-specific QueryLoader, or am I not seeing a better way
> of
> > > leveraging the existing QueryLoader class?
> >
> > QueryLoader isn't used by other DbUtils classes; it's just a
> standalone
> > helper class that loads queries from properties files. So, you won't
> gain
> > anything by subclassing it and replacing it with a DB lookup.
> >
> > David
>
>
> Thanks for the response. Keeping a registry of named queries seems like
> a
> common thing to do and I see lots of utility in having a helper class
> like
> QueryLoader to do it with. I was hoping I could easily change
> QueryLoader's
> behavior so it would look for it's name/query mapping somewhere other
> than a
> properties file, but alas, it's such a simple problem it's no big deal
> to handle
> this in my own code with another class.
You could subclass QueryLoader but you wouldn't be gaining anything.
>
> On another note isn't it risky to return a reference to queryMap below
> without
> first wrapping it in Collections.unmodifiableMap( queryMap ) ? I lack
> trust.
You could consider that a feature if you wanted to load an initial set of
queries from a file and then dynamically change them at runtime.
QueryLoader doesn't depend on the state of the Maps for it to function
properly so there's no need to wrap it in an unmodifiable view.
David
>
> public synchronized Map load(String path) throws IOException {
> Map queryMap = (Map) this.queries.get(path);
> if (queryMap == null) {
> queryMap = this.loadQueries(path);
> this.queries.put(path, queryMap);
> }
> return queryMap;
> }
>
> thanks...
> hernan
>
>
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