acoelhosantos/dropwizard-hk2bundle

Dropwizard hk2 integration bundle

Dropwizard hk2 Bundle

Simple dropwizard bundle for autodiscovery and injection of dropwizard managed objects, tasks etc using hk2 integration

Features

• Auto registration and injection for:
  • Healthchecks
  • Managed objects
  • Lifecycle listeners
  • Tasks
  • Commands
  • HK2 Binders
  • Other bundles
• Hibernate validators injections
• Jdbi DAOs injections
• Support for injections before Jersey initialisation

Usage

Gradle

repositories {
    maven { url "https://jitpack.io" }
}

dependencies {
    compile 'com.github.alex-shpak:dropwizard-hk2bundle:0.4.1'
    compile 'org.glassfish.hk2:hk2-metadata-generator:2.4.0'
}

Maven

<repositories>
    <repository>
        <id>jitpack.io</id>
        <url>https://jitpack.io</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>com.github.alex-shpak</groupId>
        <artifactId>dropwizard-hk2bundle</artifactId>
        <version>0.4.1</version>
    </dependency>
    <dependency>
        <groupId>org.glassfish.hk2</groupId>
        <artifactId>hk2-metadata-generator</artifactId>
        <version>2.4.0</version>
    </dependency>
</dependencies>

Code

Add bundle to your dropwizard application

bootstrap.addBundle(HK2Bundle.with(this).build());

All classes that you want to be discovered or injected should be annotated with @org.jvnet.hk2.annotations.Service annotation

@Service
public class DatabaseHealthCheck extends HealthCheck {

    @Inject 
    private Provider<Database> database;

    @Override
    protected Result check() throws Exception {
        if(database.get().isConnected()) {
            return Result.healthy();
        }
        return Result.unhealthy("Not connected");
    }
}

JDBI DAO Injection

Considering you already has dropwizard-jdbi module in dependencies, add JDBIBinder to HK2Bundle configuration. Then you would be able to inject DAOs.

HK2Bundle hk2bundle = HK2Bundle.with(this)
        .bind(new JDBIBinder(config -> config.database))
        .build();
bootstrap.addBundle(hk2bundle);

@Inject
private MyDAO myDAO;

How it works

Hk2bundle initializes new ServiceLocator and binds found services into it. Then it sets created ServiceLocator as parent of jersey's ServiceLocator

environment.getApplicationContext().setAttribute(
    ServletProperties.SERVICE_LOCATOR, serviceLocator
);

After jersey initialisation services (if enabled) will be re-injected with new ServiceLocator

Without hk2 metadata generator

If you don't want to use metadata generator you can bind services manually using AbstractBinder supplied to bundle constructor

public class Binder extends AbstractBinder {

    @Override
    protected void configure() {
        bind(DatabaseHealthCheck.class)
            .to(HealthCheck.class)
            .in(Singleton.class);
    }
}

bootstrap.addBundle(HK2Bundle.with(this)
        .bind(new Binder())
        .build()
);

Licence

MIT