Thank you! This worked great and is very clean and simple.
This is what I did:
Created DogModule which extends AnimalModule
Now all the config reading and validation boilerplate is done in
Animal and inherited by Dog.
In DogModule I do:
@Provides
Animal provideDog() {
Animal dog = new Dog(
config.getString("dog.breed"),
config.getInt("dog.weight"),
...
);
return dog;
}
and in my main method I do:
/* Initialize Guice module for plugin. */
AbstractModule module = (AbstractModule)
Class.forName(config.getString("Animal")).newInstance();
Injector injector = Guice.createInjector(module);
/* Get animal instance. */
Animal animal = injector.getInstance(Animal.class);
-leo
On May 18, 11:54 am, Jean-Francois Poilpret <[email protected]>
wrote:
> I wouldn't advise you to code the class to be instantiated, along with
> constructor arguments, in a property file.
> I think a much better way is to:
> - create a DogModule (in addition to any other, more general, Module)
> that binds Animal.class to Dog or provides a Dog)
> - implement some kind of discovery of Modules in the classpath (this
> could possibly go also in a property file, to make it simpler), and add
> each of the discovered modules.
>
> If you want to replace the Dog with a Cat, then you would have to
> replace DogModule with CatModule.
>
> On 18-05-2011 19:13, leo wrote:
>
>
>
>
>
>
>
> > Hi. I just started to experiment with Guice and have a question. What
> > is the best way to do the following:
>
> > - I have an abstract class Animal
> > - Want to start the application with a specific implementation of the
> > Animal class say Dog
> > - I specify "animalClass = Dog" in a properties file.
> > - To create a Dog I need to pass many parameters, say:
> > dog.breed = pitbull
> > dog.weight = 40
> > ...
>
> > In AnimalModule I do this:
>
> > @Provides
> > Animal provideDog() {
> > Animal dog = new Dog(
> > config.getString("dog.breed"),
> > config.getInt("dog.weight"),
> > ...
> > );
> > return dog;
> > }
>
> > This works fine. I can get my dogs in some class as follows:
>
> > Injector injector = Guice.createInjector(new AnimalModule());
>
> > Animal dog = injector.getInstance(Dog.class);
>
> > My question is how can I do this without hardcoding Dog in the module.
> > Say tomorrow I want to create a Cat with another set of parameters. I
> > can see how to load components in Spring and other frameworks but I
> > want to keep this lightweight and I don't want to write framework code
> > to do this with reflection. Thoughts?
>
> > Thanks,
> > -leo
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