dropwizard-guice-box

A slightly different take on Guice integration with DropWizard, which makes heavy use of multibindings to create a more plugin-like, modular experience.

Installation

Add the dependency to your POM:

<dependency>
  <groupId>com.gruelbox</groupId>
  <artifactId>dropwizard-guice-box</artifactId>
  <version>0.0.2</version>
</dependency>

Usage

public class MyApplication extends Application<MyConfiguration> {

  @Inject private SomethingINeed somethingINeed;

  @Override
  public void initialize(final Bootstrap<MyConfiguration> bootstrap) {
    super.initialize(bootstrap);
    bootstrap.addBundle(
      new GuiceBundle<MyConfiguration>(
        this,
        new MyApplicationModule(),
        new MyOtherApplicationModule()
      )
    );
  }

  @Override
  public void run(final MyConfiguration configuration, final Environment environment) {
    somethingINeed.canNowBeUsed();
  }
}

You now have access to some Guice idiomatic bind points in your Modules:

Multibindings to WebResource provide resources.
Multibindings to HealthCheck provide healthchecks.
Multibindings to Managed provide controlled startup and shutdown of components.
Multibindings to Service provide controlled startup and shutdown of background processes.
Multibindings to EnvironmentInitialiser allow you to hook into the Application.run phase directly from anywhere in your code when you need to do anything else on startup.

All of these can inject as normal, and all except WebResource can be package private, aiding encapsulation (unfortunately, JAX-WS prevents this for JAX-RS resources).

The following are provided by default for injection:

Your application configuration
The Environment
The HttpServletRequest and HttpServletResponse during web requests (thanks to GuiceFilter).

In addition, any Module provided directly to GuiceBundle can support the Configured interface to gain access to the application configuration during bind time.

Hibernate

If you're using Dropwizard's Hibernate bundle, you can provide your @Entity classes via injection too, which is great for keeping underlying database structure encapsulated in your modules.

Add the dependency:

<dependency>
  <groupId>com.gruelbox</groupId>
  <artifactId>dropwizard-guice-box-hibernate</artifactId>
  <version>0.0.2</version>
</dependency>

And modify your code to construct and install the HibernateBundle, replacing the example DataSourceFactory configuration in the example with your requirements:

public class MyApplication extends Application<MyConfiguration> {

  @Inject private SomethingINeed somethingINeed;

  @Override
  public void initialize(final Bootstrap<MyConfiguration> bootstrap) {
  
    super.initialize(bootstrap);
    
    HibernateBundleFactory<MyConfiguration> hibernateBundleFactory = new HibernateBundleFactory<>(configuration -> {
      DataSourceFactory dsf = new DataSourceFactory();
      dsf.setDriverClass(configuration.getDriverClass());
      dsf.setUrl(configuration.getJdbcUrl());
      // etc...
      return dsf;
    });
    
    bootstrap.addBundle(
      new GuiceBundle<MyConfiguration>(
        this,
        new MyApplicationModule(),
        new MyOtherApplicationModule(),
        new GuiceHibernateModule(hibernateBundleFactory)
      )
    );
    
    bootstrap.addBundle(hibernateBundleFactory.bundle());
  }

  @Override
  public void run(final MyConfiguration configuration, final Environment environment) {
    somethingINeed.canNowBeUsed();
  }
}

You now have access to both SessionFactory and HibernateBundle via injection, and can multi-bind implementations of EntityContribution to provide JPA entities at runtime, as you would with WebResource, Healthcheck etc.

Examples

See the tests for some basic examples.

Credit