Dropwizard: Guice Bundle

In this tutorial I will show you how to add Guice to your Dropwizard app. This will be a very basic implementation. Some things you should note is that I didn’t put in any docstrings. You should always do that!

Now there are a few Dropwizard Guice integrations available but the most active is the one I will show you today called “dropwizard-guicey“.

POM.xml

<dependency>
	<groupId>ru.vyarus</groupId>
	<artifactId>dropwizard-guicey</artifactId>
	<version>4.1.0</version>
</dependency>

Model

Now we create a model to use with our service

package ca.gaudreault.mydropwizardapp.models;

import java.io.Serializable;

import javax.validation.constraints.NotNull;

public class MyModel implements Serializable {
	private static final long serialVersionUID = 1L;
	private Integer value;
	
	public Integer getValue() {
		return value;
	}
	public void setValue(Integer value) {
		this.value = value;
	}
}

Service

Here you will create your service interface and class so that you can bind it in the guice module.

Interface

package ca.gaudraeult.mydropwizardapp.services;

import ca.gaudreault.mydropwizardapp.models.MyModel;

public interface MyService {
	MyModel runTest();
}

Implementation

package ca.gaudraeult.mydropwizardapp.services;

import ca.gaudreault.mydropwizardapp.models.MyModel;

public class MyServiceImpl implements MyService {
	
	public MyServiceImpl() { }

	@Override
	public MyModel runTest() {
		final MyModel myModel = new MyModel();
		myModel.setValue(123123);
		return myModel;
	}
}

ServerModule

Now when we create our module class you can bind the interface to the implementation. Note that if your implementation does not implement the interface this will not work.

package ca.gaudreault.mydropwizardapp;

import com.google.inject.AbstractModule;

import ca.gaudraeult.mydropwizardapp.services.MyService;
import ca.gaudraeult.mydropwizardapp.services.MyServiceImpl;

public class ServerModule extends AbstractModule  {

	@Override
	protected void configure() {
		bind(MyService.class).to(MyServiceImpl.class);
	}
}

Dropwizard Application

If you remember from part 1 of this series you created the based Dropwizard app. So you should have a class called “MyDropwizardAppApplication”. Open that now and modify the “initialize” like the below. Baseically here we are registering our ServerModule class to Dropwizard.

@Override
public void initialize(final Bootstrap bootstrap) {
	bootstrap.addBundle(GuiceBundle.builder()
		.enableAutoConfig(this.getClass().getPackage().getName())
		.modules(new ServerModule())
		.build());
}

And that is it you have configured a very basic Dropwizard Guice configuration.