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Injector instance

Restrictive options

Guicey is compatible with the following guice restrictive options:

public class MyModule extends AbstractModule {
        @Override
        protected void configure() {
            binder().disableCircularProxies();
            binder().requireExactBindingAnnotations();
            binder().requireExplicitBindings();
        }
    }

Access injector

In some cases it may be important to get injector instance outside of guice context.

Warning

Injector is created on dropwizard run phase. Attempt to obtain injector before it will lead to exception.

Injector instance could be resolved with:

• GuiceBundle#getInjector() method on instance (exception thrown if not yet started)
• InjectorLookup.getInjector(app).get() static call using application instance (lookup returns Optional for null safety).

If you need lazy injector reference, you can use InjectorProvider class (Provider<Injector>):

Provider<Injector> provider = new InjectorProvider(app);
// somewhere after run phase
Injector injector = provider.get();

Bean instance may be obtained with getInstance shortcut:

public class MyApplication extends Application<Configuration> {

    @Override
    public void run(TestConfiguration configuration, Environment environment) throws Exception {
        InjectorLookup.getInstance(this, SomeService.class).get().doSomething();
    }
}

Injector could also be referenced by Environment object:

InjectorLookup.getInstance(environment, SomeService.class).get().doSomething();

Tip

Most likely, requirement for injector instance means integration with some third party library. Consider writing custom installer in such cases (it will eliminate need for injector instance).

Inside guice context you can simply inject Injector instance:

@Inject Injector injector;

Injector stage

By default injector is created at PRODICTION stage, which means that all registered singletons are instantiated in time of injector craetion.

You can change stage at main bundle:

GuiceBundle.builder()
    ...
    .build(Stage.DEVELOPMENT)

Injector factory

You can control guice injector creation through ru.vyarus.dropwizard.guice.injector.InjectorFactory.

Default implementation is very simple:

public class DefaultInjectorFactory implements InjectorFactory {

    @Override
    public Injector createInjector(final Stage stage, final Iterable<? extends Module> modules) {
        return Guice.createInjector(stage, modules);
    }
}

Injector creation customization may be required by some 3^rd party library. For example, netflix governator owns injector creation (see example).

Custom injector factory could be registered in guice bundle builder:

bootstrap.addBundle(GuiceBundle.builder()
            .injectorFactory(new CustomInjectorFactory())
            ...