On 28 Oct 2011, at 18:43, Jeff wrote:
> Thanks for the great info and helping me work things out. The fog is
> clearing.
>
> Since my language provider depends on the environment, is it kosher to do
> something like:
> @Provides @Named("ENV") @Singleton
> public Properties EnvironmentProvider() {
> //setup env
> return env;
> }
>
> @Provides @Named("LANG") @Singleton @Inject
^ you shouldn't need @Inject here since every parameter in a @Provides method
will always be injected
> public Properties LanguageProvider(@Named("ENV") Properties env) {
> //load language files based on lang setting in env
> return lang;
> }
> And if I mark these as @Singleton, am I the one that needs to store and
> manage the instance or does Guice cache the object returned for lang and env
> and never call this method directly again?
Guice will apply the scoping around the @Provides method, so you don't need
cache the result yourself
> On Fri, Oct 28, 2011 at 6:32 AM, Stuart McCulloch <[email protected]> wrote:
> On 27 Oct 2011, at 21:12, Jeff wrote:
>
>> The classes containing the injected fields are TestNG test classes. I am
>> creating the Injector using the ServiceLoader mechanism within a class that
>> implements org.testng.ISuiteListener. TestNG automatically picks up and
>> runs the onStart() method before doing anything else and I call
>> createInjector() there.
>>
>> Though, I think I just realized my problem (besides trying to learn/use
>> Guice from within another framework I'm also just learning).
>>
>> The key bit I had not grasped previously was that for Guice/@Inject to work,
>> object instantiation must be done directly by Guice
>> (Injector.getInstance()), at least for the root node of the object graph (I
>> think).
>>
>> Since TestNG instantiates classes without Guice by default, it was just
>> creating normal instances and the @Inject annotations weren't getting
>> processed.
>>
>> TestNG does support Guice via @Test(guiceModule = MyModule.class)
>> annotation, but I wanted to avoid the need to put this on EVERY test class
>> and thought I could insert my Modules/Providers and enable my custom
>> bindings to work globally.
>>
>> I'm still playing with my code, but I feel like I'm on the right track. Can
>> anyone confirm or help me understand if there is a different way?
>
> Yes, either the root of the object graph needs to be instantiated by Guice or
> you need to use injectMembers(...) to inject an existing instance (in which
> case you can't use constructor injection in that particular class). Of course
> one benefit of putting @Test(guiceModule=...) on each test class (or @Guice
> in the latest version:
> http://testng.org/doc/documentation-main.html#guice-dependency-injection) is
> that it documents that you're using dependency injection for that test, and
> with modern IDEs it's not too hard to add this automatically or use a
> template. Also note the latest release of TestNG supports module factories so
> you could use the same factory across all your tests:
> http://testng.org/javadocs/org/testng/IModuleFactory.html
>
>> Thanks!!
>>
>> On Thu, Oct 27, 2011 at 5:40 AM, Stuart McCulloch <[email protected]> wrote:
>> On 27 Oct 2011, at 06:14, Jeff wrote:
>>
>>> I want to do something like:
>>> @Inject @Named("conf")
>>> Properties config;
>>>
>>> @Inject @Named("lang")
>>> Properties language;
>>> Where these objects are singletons initialized once at runtime with
>>> environment-specific information.
>>>
>>> I've tried various things and none result in my Provider or @Provides
>>> methods getting called. Here is a trimmed down version of my code using a
>>> Provider class:
>>>
>>> MyModule.java:
>>> public class SeleniumInjectionModule extends AbstractModule {
>>> @Override
>>> protected void configure() {
>>>
>>> bind(Properties.class).annotatedWith(Names.named("conf")).toProvider(ConfigProvider.class);
>>>
>>> bind(Properties.class).annotatedWith(Names.named("lang")).toProvider(LanguageProvider.class);
>>> }
>>> }
>>> ConfigProvider.java:
>>> @Singleton
>>> public class ConfigProvider implements Provider<Properties> {
>>> private final Properties config = new Properties();
>>>
>>> public ConfigProvider() {
>>> //Load properties file based on 'config' system property value set in
>>> Maven profile
>>> ...
>>> config.load(...);
>>> ...
>>> }
>>> @Override
>>> public Properties get() {
>>> return config;
>>> }
>>> }
>>>
>>> LanguageProvider.java:
>>> @Singleton
>>> public class LanguageProvider implements Provider<Properties> {
>>> private final Properties lang = new Properties();
>>>
>>> public LanguageProvider() {
>>> //Load properties file based on 'language' system property value set in
>>> Maven profile
>>> ...
>>> lang.load(...);
>>> ...
>>> }
>>> @Override
>>> public Properties get() {
>>> return lang;
>>> }
>>> }
>>> In my Global Init code:
>>> Guice.createInjector(new MyModule());
>>>
>>> What am I missing?
>>
>> Where's the class containing the injected config/language fields mentioned
>> in the start of this email?
>>
>> Assuming that class is called Foo then you need to use
>> injector.getInstance(Foo.class) - or injector.injectMembers(myFoo) if you
>> already have an instance of Foo - to start the injection process and inject
>> those fields. Note that you don't need to do this for everything, just the
>> class at the beginning of the injection graph to kick things off.
>>
>>> --
>>> Jeff Vincent
>>> [email protected]
>>> See my LinkedIn profile at:
>>> http://www.linkedin.com/in/rjeffreyvincent
>>> I ♥ DropBox !!
>>>
>>>
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>>
>>
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>>
>>
>> --
>> Jeff Vincent
>> [email protected]
>> See my LinkedIn profile at:
>> http://www.linkedin.com/in/rjeffreyvincent
>> I ♥ DropBox !!
>>
>>
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>
>
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>
>
> --
> Jeff Vincent
> [email protected]
> See my LinkedIn profile at:
> http://www.linkedin.com/in/rjeffreyvincent
> I ♥ DropBox !!
>
>
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