Add Controllers approach in getting started

Author: decebals

_posts/2015-03-17-getting-started.md

@@ -9,6 +9,8 @@ order: 10
 We provide a pippo-demo module that contains many demo applications (submodules): pippo-demo-basic and pippo-demo-crud are some.  
 For a list with all demo please see [Demo](demo.html) section.
 
+#### Routes approach 
+
 For [pippo-demo-basic]({{ site.demourl }}/pippo-demo-basic) you have two java files: [BasicDemo.java]({{ site.demourl }}/pippo-demo-basic/src/main/java/ro/pippo/demo/basic/BasicDemo.java) and [BasicApplication.java]({{ site.demourl }}/pippo-demo-basic/src/main/java/ro/pippo/demo/basic/BasicApplication.java)  
 We split our application in two parts for a better readability.
 
@@ -99,4 +101,55 @@ Open your internet browser and check the routes declared in Application:
  - `http://localhost:8338/negotiate`
  - `http://localhost:8338/template` 
  
+#### Controllers approach
+
+Another approach to handling a request and producing a response is using Controllers. After routing has determined what controller to use, an action method will be invoked.
+In Pippo, controllers are instances of [Controller]({{ site.codeurl }}/pippo-controller-parent/pippo-controller/src/main/java/ro/pippo/controller/Controller.java).
+
+Defining a new controller is simple:
+
+```java
+@Path("/contacts")
+public class ContactsController extends Controller {
+
+    @GET("/?")
+    public void index() {
+		List<Contact> contacts = contactService.getContacts();
+		getResponse().bind("contacts", contacts).render("contacts");
+    }
+    
+    @GET("/{id: [0-9]+}")
+    public void getContact(@Param int id) {
+        Contact contact = contactService.getContact(id);
+        getResponse().bind("contact", contact).render(contact);
+    }
+
+    @GET("/text")
+    @Named("text")
+    @Produces(Produces.TEXT)
+    @NoCache
+    public void complex(@Param int id, @Param String action, @Header String host, @Session String user) {
+        // do something
+    }
+    
+}
+```
+
+Methods attached to the controller (for example `index` from above snippet) are known as action methods. When Pippo receives a request, it will create a new instance of the controller and call the appropriate action method.
+You can register a controller's action in application with a simple line:
+
+```java
+public class BasicApplication extends ControllerApplication {
+
+    @Override
+    protected void onInit() {
+        // add controller(s)
+        addControllers(ContactsController.class); // one instance for EACH request
+        // or
+        addControllers(new ContactsController()); // one instance for ALL requests        
+    }
+
+}
+```
+ 
 For a detailed overview please see section [Under the hood](/dev/under-the-hood.html).