Configuring Atmosphere's Classes Creation and Injection

Custom Object creation and Injection

Starting with Atmosphere 2.1, it is possible to configure an AtmosphereObjectFactory for dependencies injection and class creation. You can define your own and pass it to the framework by defining an init-param:

<init-param>
  <param-name>org.atmosphere.cpr.objectFactory</param-name>
  <param-value> << an implementation of AtmosphereObjectFactory >> </param-value>
</init-param>

Built In Framework Support

Using Contexts and Dependency Injection (CDI)

By default, Atmosphere will use the following code for injecting/creating object:

public class CDIObjectFactory implements AtmosphereObjectFactory {
    @Override
    @SuppressWarnings("unchecked")
    public <T> T newClassInstance(AtmosphereFramework framework, Class<T> classToInstantiate) throws InstantiationException, IllegalAccessException {
        CreationalContext cc = null;

        final BeanManager bm;
        try {
            bm = (BeanManager) new InitialContext().lookup("java:comp/BeanManager");
            final Iterator<Bean<?>> i = bm.getBeans(classToInstantiate).iterator();
            if (!i.hasNext()) {
                return classToInstantiate.newInstance();
            }
            Bean<T> bean = (Bean<T>) i.next();
            CreationalContext<T> ctx = bm.createCreationalContext(bean);
            T dao = (T) bm.getReference(bean, classToInstantiate, ctx);
            return dao;
        } catch (Exception e) {
            // Log ME. Fallback to normal.
            return classToInstantiate.newInstance();
        } finally {
            if (cc != null) cc.release();
        }
    }
}

You can install it by adding in your pom.xml:

 <dependency>
    <groupId>org.atmosphere</groupId>
    <artifactId>atmosphere-cdi</artifactId>
    <version>2.1.0</version>
</dependency>

Atmosphere will auto-detect it and use it automatically.

Using Spring

By default, Atmosphere will use the following code for injecting/creating object:

public class SpringObjectFactory implements AtmosphereObjectFactory {
    @Override
    public <T> T newClassInstance(AtmosphereFramework framework, Class<T> tClass) throws InstantiationException, IllegalAccessException {
        ApplicationContext context =
            new AnnotationConfigApplicationContext(classToInstantiate);
        T t = context.getBean(classToInstantiate);
        if (t == null) {
            logger.info("Unable to find {}. Creating the object directly.", classToInstantiate.getName());
            return classToInstantiate.newInstance();
        }
        return t;
    }
}

You can install it by adding in your pom.xml:

 <dependency>
    <groupId>org.atmosphere</groupId>
    <artifactId>atmosphere-spring</artifactId>
    <version>2.1.0</version>
</dependency>

Using Guice

By default, Atmosphere will use the following code for injecting/creating object:

public class GuiceObjectFactory implements AtmosphereObjectFactory {
    private static final Logger logger = LoggerFactory.getLogger(GuiceObjectFactory.class);
    private static Injector injector;
    static {
        injector = Guice.createInjector(new AbstractModule() {
            @Override
            protected void configure() {
            }
        });
    }

    @Override
    public <T> T newClassInstance(AtmosphereFramework framework, Class<T> classToInstantiate) throws InstantiationException, IllegalAccessException {
        com.google.inject.Injector servletInjector = (com.google.inject.Injector)
                framework.getServletContext().getAttribute(com.google.inject.Injector.class.getName());

        if (servletInjector != null) {
            injector = servletInjector;
        }

        if (injector == null) {
            logger.warn("No Guice Injector found in current ServletContext. Are you using {}", AtmosphereGuiceServlet.class.getName());
            logger.trace("Unable to find {}. Creating the object directly.", classToInstantiate.getName());
            return classToInstantiate.newInstance();
        }
        return injector.getInstance(classToInstantiate);
    }
}

You can install it by adding in your pom.xml:

 <dependency>
    <groupId>org.atmosphere</groupId>
    <artifactId>atmosphere-guice</artifactId>
    <version>2.1.0</version>
</dependency>