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From po...@free.fr
Subject Re: DbUtils Best Practices
Date Thu, 13 Sep 2007 09:51:57 GMT
i'm seeing another point. Your QueryManager does not offer the guarantee to be a
singleton, you have to declare a private constructor.

Jérome.


Selon pouky@free.fr:

> Selon diego.galdi@nurun.it:
>
> > Hi,
> > I'm using a dao pattern, the call
> >
> > QueryManager.getInstance().getQueryRunner().query(...);
> >
> > is executed in my dao object.
> >
> > Servlet calls dao method.
> >
> ok.
>
> > What do you mean with it depends of your project size?
> Hi,
> If you have a small project it is not mandatory to spend a lot of time in the
> abstraction layers, but this is advised. If you implement this approach, life
> is
> wonderful. :)
>
> Jérome.
>
> >
> > Thanks a lot
> >
> > Diego
> >
> >
> > > Hi,
> > > It seems correct, why not, QueryRunner object is thread safe.
> > > Web layer which calls integration layer directly, it's a bad design but
> > > this
> > > depends of your project size.
> > >
> > > Jérome.
> > >
> > >
> > >
> > > Selon diego.galdi@nurun.it:
> > >
> > >> Hi, I'm developing a web application using DbUtils classes to execute
> > >> queries and so on.
> > >>
> > >> I user QueryRunner class with a DataSource.
> > >>
> > >> I red this class is thread safe, so I implemented a Singleton to
> > >> instance
> > >> QueryRunner only once.
> > >>
> > >> This is my code:
> > >>
> > >> public class QueryManager {
> > >>
> > >>  private static QueryManager queryManager = null;
> > >>
> > >>  private static QueryRunner queryRunner = null;
> > >>
> > >>  static {
> > >>    try {
> > >> 	queryRunner = new QueryRunner(DataSourceSingleton.getInstance()
> > >> 					.getDataSource());
> > >> 	} catch (Exception e) {
> > >> 	}
> > >>  }
> > >>
> > >>  public static QueryManager getInstance() {
> > >>     if (queryManager == null) {
> > >> 	queryManager = new QueryManager();
> > >>     }
> > >>     return queryManager;
> > >>  }
> > >>
> > >>  public QueryRunner getQueryRunner() {
> > >>    return queryRunner;
> > >>  }
> > >>
> > >> In my servlets I use:
> > >>
> > >> QueryManager.getInstance().getQueryRunner().query(...);
> > >>
> > >> Is this correct?
> > >>
> > >> Which is the best practice to use QueryRunner in a web context?
> > >>
> > >> Thanks a lot in advance
> > >>
> > >>
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> > >>
> > >>
> > >
> > >
> > >
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> > >
> >
> >
> >
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> >
> >
>
>
>
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