Improve Modularity section

Author: decebals

_posts/2015-03-17-modularity.md

@@ -8,15 +8,16 @@ order: 120
 
 Pippo was designed since the first version with the modularity in mind. Many aspects (extension points) of this framework can be changed:
 
-- `WebServer` (using _Pippo setServer()_ or auto discovery mechanism)
-- `TemplateEngine` (using _Application.setTemplateEngine()_ or auto discovery mechanism)
+- `WebServer` (using _Pippo#setServer()_ or auto discovery mechanism)
+- `TemplateEngine` (using _Application#setTemplateEngine()_ or auto discovery mechanism)
 - `Router` (using _Application.setRouter()_)
-- `ErrorHandler` (using _Application.setErrorHandler()_)
+- `ErrorHandler` (using _Application#setErrorHandler()_)
+- `ContentTypeEngine` (using _Application#registerContentTypeEngine_)
 
-Also you can set some parameters related to file upload process (_Application.setUploadLocation()_ and _Application.setMaximumUploadSize()_).
+Also you can set some parameters related to file upload process (_Application#setUploadLocation()_ and _Application#setMaximumUploadSize()_).
 You can modify some settings for an embedded WebServer using _WebServerSettings_.
 
-We chose the Service Loader mechanism from Java as built in modules system in Pippo because is a standard and easy to use.
+We chose the ServiceLoader mechanism from Java as built in modules system in Pippo because is a standard and easy to use.
 You can create a modular application using [ServiceLocator]({{ site.coreurl }}/src/main/java/ro/pippo/core/util/ServiceLocator.java) class (trivial wrapper over Service Loader concept).
 
 To improve the modularity mechanism, we added the concept of [Initializer]({{ site.coreurl }}/src/main/java/ro/pippo/core/Initializer.java).  
@@ -60,7 +61,12 @@ public class ContactInitializer implements Initializer {
         application.GET("/contacts", routeContext -> routeContext.render("contacts"));
 
         // show contact page for the contact with id specified as path parameter 
-        application.GET("/contact/{id}", routeContext -> routeContext.render("contact"));
+        application.GET("/contact/{id}", routeContext -> {
+            int id = routeContext.getParameter("id").toInt(0);
+            Map<String, Object> model = new HashMap<>();
+            model.put("id", id);
+            routeContext.render("contact", model);
+        });
     }
 
     @Override
@@ -83,7 +89,12 @@ public class UserInitializer implements Initializer {
         application.GET("/users", routeContext -> routeContext.render("users"));
 
         // show user page for the user with id specified as path parameter 
-        application.GET("/user/{id}", routeContext -> routeContext.render("user"));
+        application.GET("/user/{id}", routeContext -> {
+            int id = routeContext.getParameter("id").toInt(0);
+            Map<String, Object> model = new HashMap<>();
+            model.put("id", id);
+            routeContext.render("user", model);
+        });
     }
 
     @Override
@@ -94,4 +105,63 @@ public class UserInitializer implements Initializer {
 }
 ```
 
+The above example can be improved as readability if we use the `RouteGroup` concept described in [Routes](/doc/routes.html) section
+```java
+public class ContactRoutes extends RouteGroup {
+
+    public UserRoutes() {
+        super("/contact");
+
+        GET("/", routeContext -> routeContext.render("contacts"));
+        GET("/{id: [0-9]+}", routeContext -> {
+            int id = routeContext.getParameter("id").toInt(0);
+            Map<String, Object> model = new HashMap<>();
+            model.put("id", id);
+            routeContext.render("contact", model);
+        });
+    }
+
+}
+```
+
+```java
+@MetaInfServices
+public class ContactInitializer implements Initializer {
+
+    @Override
+    public void init(Application application) {
+        application.addRouteGroup(new ContactRoutes());
+    }
+}
+```
+
+```java
+public class UserRoutes extends RouteGroup {
+
+    public UserRoutes() {
+        super("/user");
+
+        GET("/", routeContext -> routeContext.render("users"));
+        GET("/{id: [0-9]+}", routeContext -> {
+            int id = routeContext.getParameter("id").toInt(0);
+            Map<String, Object> model = new HashMap<>();
+            model.put("id", id);
+            routeContext.render("user", model);
+        });  
+    }
+
+}
+```
+
+```java
+@MetaInfServices
+public class UserInitializer implements Initializer {
+
+    @Override
+    public void init(Application application) {
+        application.addRouteGroup(new UserRoutes());
+    }
+}
+```
+
 >__NOTE__ The order of the initializers depends on the order of the jars in the classpath.