Well, this is why I am currently working on osgi. Switching modules seems
to imply some coupling you probably don't want.
That said, without osgi, here's what we do: parse a list of modules, adding
defaults if no overrides are present. How you add additional modules could
be a varargs factory method (Module ... modules),
Class.forName(overrideModuleName), etc.
Here's an example how we inspect modules to satisfy the requirements of our
code.
private Injector createInjector() {
useDefaultPortIfNotPresent(properties);
addLoggingModuleIfNotPresent(modules);
addS3ParserModuleIfNotPresent(modules);
addS3ConnectionModuleIfNotPresent(modules);
addHttpModuleIfNeededAndNotPresent(modules);
modules.add(new AbstractModule() {
@Override
protected void configure() {
Names.bindProperties(binder(), checkNotNull(properties,
"properties"));
}
});
modules.add(new S3ContextModule());
return Guice.createInjector(modules);
}
I hope this helps.
-Adrian
On Sat, Jun 27, 2009 at 9:45 AM, Karthik Krishnan
<krishnan.1...@gmail.com>wrote:
>
> Adrian: Thanks for your reply: For unit tests, I am mocking behavior
> for the dao class. Ideally I would like to use DM based datasources
> for my integration tests and JNDI based data sources for my
> application to unit test the entire work flow.
>
> In Spring it is so easy to do this. I just swap one xml with another
> and let Spring framework handling the switch seamlessly. Idon't know
> how to get Guice to do it for me without having to change the module
> instance.
>
> On Jun 26, 11:51 pm, Adrian Cole <fernc...@gmail.com> wrote:
> > Hi, Krishnan,
> >
> > I'd extract MyDao's interface and move the other code to DataSourceMyDao.
> > For unit tests, you can mock the behaviour in MyDao specific to that
> test.
> > pita perhaps, but fairly normal. Creating a more versatile StubMyDao
> would
> > involve some work. In jclouds, this proved useful, as it helps you load
> > test your code, as opposed to your db.
> >
> > All this said, you could always fire up an in-process db like derby or
> > hsqldb. Less work, but it isn't really unit testing at that point ;)
> >
> > my 2p.
> > -Adrian
> > jclouds <http://code.google.com/p/jclouds>
> >
> > On Sat, Jun 27, 2009 at 7:57 AM, Karthik Krishnan
> > <krishnan.1...@gmail.com>wrote:
> >
> >
> >
> > > Hi Guice Gurus,
> >
> > > I am just playing with Guice 2.x and I am stuck with an issue that I
> > > can not resolve. Any help would be appreciated.
> >
> > > I have a service class that takes DAO class as a constructor argument
> > > that connects to the data base. The dao class accepts a data source as
> > > a constructor argument. I have created two modules : the first one
> > > injects a JNDI based data source, the other DriverManager based data
> > > source. I would like
> >
> > > public class MyService {
> >
> > > private final MyDao myDao;
> >
> > > public MyService(MyDao myDao) {
> > > this.myDao = myDao;
> > > }
> >
> > > ....
> >
> > > }
> >
> > > public class MyDao {
> > > private final DataSource dataSource;
> >
> > > @Inject
> > > public MyDao(DataSource dataSource) {
> > > this.dataSource = dataSource;
> > > }
> >
> > > ....
> > > }
> >
> > > My modules:
> >
> > > public class JndiDataSourceModule extends AbstractModule {
> >
> > > public void configure() {
> > > bind(DataSource.class).toProvider(JndiIntegration.fromJndi
> > > (DataSource.class, "myDatasource"));
> > > }
> > > }
> >
> > > public class DriverManagerDataSourceModule extends AbstractModule {
> > > @Provides
> > > DataSource getDataSource() {
> > > return DriverManagerDataSource(driverClass, url, username,
> > > password);
> > > }
> >
> > > ....
> > > }
> >
> > > I can not figure out how to inject DriverManager based DataSource for
> > > unit tests and JNDI based datasource in my application. I was thinking
> > > of passing modules in the constructor of my service class but I don't
> > > think I would be able to mock my MyDao for exceptional conditions.
> > > Any help would be appreciated.
> >
>
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