MVC 1.0 - by Example @ Devoxx Belgium 2015

@rgielen / @ivar_grimstad
#Devoxx #JSR371
JSR 371
MVC 1.0 for Java EE 8

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#Devoxx #JSR371
Ivar Grimstad
Principal Consultant for
Cybercom Sweden
JSR 371 Expert Group Member

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#Devoxx #JSR371
René Gielen
Independent Software
Craftsman, Consultant, Trainer
Apache Struts PMC Chair

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#Devoxx #JSR371

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#Devoxx #JSR371
Front Controller

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#Devoxx #JSR371
Action

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Request

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Response

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#Devoxx #JSR371
Serious Business

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#Devoxx #JSR371

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#Devoxx #JSR371
Action vs. Component
Component based
Complex Stateful Components
Abstract away Request-Response
Action based
Abstract away Technical Details of HTTP
Stateless
Embrace Request-Response

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#Devoxx #JSR371

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#Devoxx #JSR371
Introduction to JSR 371

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#Devoxx #JSR371
Why?

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#Devoxx #JSR371
https://java.net/downloads/javaee-spec/JavaEE8_Community_Survey_Results.pdf

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#Devoxx #JSR371
http://glassﬁsh.org/survey

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#Devoxx #JSR371
Action-based MVC

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#Devoxx #JSR371
Existing Java EE Technologies

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JSR 371 Expert Group

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Key Decisions

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#Devoxx #JSR371
Build MVC 1.0 on top of JAX-RS

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#Devoxx #JSR371
Show me the CODE !

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#Devoxx #JSR371
Controllers

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#Devoxx #JSR371
public class HelloController {
}
Controller

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#Devoxx #JSR371
@Path(“hello”)
}
Controller

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@Controller
@Path(“hello”)
}
Controller

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#Devoxx #JSR371
Views

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#Devoxx #JSR371
@Controller
@Path(“hello”)
}
View

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@GET
public String hello() {
return “hello.jsp”;
}
}
View

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@GET
public Viewable hello() {
return new Viewable(“hello.jsp”);
}
}
View

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@GET
public Response hello() {
return Response.status(OK).entity(“hello.jsp”).build();
}
}
View

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@View(“hello.jsp”)
@GET
public void hello() {
}
}
View

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@GET
}
}
View

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#Devoxx #JSR371
Models

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@GET
}
}
Model

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@Named(“greeting”)
@RequestScoped
public class Greeting {
private String message;
public void setMessate(String message) {
this.message = message;
}
public void getMessage() { return message; }
}
Model

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@Inject
private Greeting greeting;
@GET
greeting.setMessage(“Hello Devoxx!”);
}
}
Model

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#Devoxx #JSR371
pageEncoding="UTF-8"%>

MVC 1.0 Hello Demo

Hello ${greeting.message}

Model

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@GET
}
}
Model

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#Devoxx #JSR371
@Controller
@Path(“hello”)
@Inject
private Models model;
@GET
model.put(“message”, “Hello Devoxx!”);
}
}
Model

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#Devoxx #JSR371
pageEncoding="UTF-8"%>

MVC 1.0 Hello Demo

Hello ${message}

Model

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#Devoxx #JSR371
View Engines

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#Devoxx #JSR371
Bring Your Own View Engine
BYOVE

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#Devoxx #JSR371
public interface ViewEngine {
boolean supports(String view);
void processView(ViewEngineContext context)
throws ViewEngineException;
}
ViewEngine

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#Devoxx #JSR371
@Priority(OUTRAGEOSLY_HIGH) 
@ApplicationScoped 
public class FreemarkerViewEngine extends ViewEngineBase {
…
}
View Engine Conﬂicts

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#Devoxx #JSR371
Validation

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#Devoxx #JSR371
@Controller
@Path("form")
public class FormController {
@POST
public Response formPost(@Valid @BeanParam FormDataBean f) {
return Response.status(OK).entity(“data.jsp”).build();
}
}
Validation
ConstraintValidationException
@Min, @NotNull
etc.

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#Devoxx #JSR371
public class FormViolationMapper implements
ExceptionMapper {
public Response toResponse(ConstraintViolationException e) {
Set> s =e.getConstraintViolations();
// process violations ...
return Response.status(BAD_REQUEST)
.entity(“error.jsp”).build();
}
}
Validation

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#Devoxx #JSR371
@Controller
@Path("form")
public class FormController {
@Inject private BindingResult br;
@POST
public Response formPost(@Valid @BeanParam FormDataBean f) {
if (br.isFailed()) {
return Response.status(BAD_REQUEST)
.entity(“error.jsp”).build();
}
return Response.status(OK).entity(“data.jsp”).build();
}
}
Validation
Allows for MVC Error Handling

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#Devoxx #JSR371
Scopes

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#Devoxx #JSR371
@Named(“greeting”)
@RedirectScoped
public class Greeting {
private String message;
public void setMessate(String message) {
this.message = message;
}
public void getMessage() { return message; }
}
@RedirectScoped

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#Devoxx #JSR371
@Controller
@Inject
@POST
@Path(“from”)
greeting.setMessage(“Hello Devoxx!”);
return “redirect:/to“;
}
}
@RedirectScoped
@RedirectScoped
@RequestScoped

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#Devoxx #JSR371
@Controller
@Inject
@POST
@Path(“to”)
return “here.jsp“;
}
}
@RedirectScoped
Same Bean

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#Devoxx #JSR371
Security

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@Controller
@Path(“csrf”)
@CsrfValid
@POST
public Response post(@FormParam(“greeting") String greet {
}
}
Cross Site Request Forgery

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#Devoxx #JSR371

MVC 1.0 Hello Demo

value="${mvc.csrf.token}"/>

Cross Site Request Forgery

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#Devoxx #JSR371
Events

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#Devoxx #JSR371
BeforeControllerEvent
AfterControllerEvent
BeforeProcessViewEvent
AfterProcessViewEvent
ControllerRedirectEvent
Currently Supported Events

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#Devoxx #JSR371
@ApplicationScoped
public class EventObserver {
void onBeforeController(@Observes BeforeControllerEvent e) {
println("URI: " + e.getUriInfo().getRequestURI());
}
void onAfterController(@Observes AfterControllerEvent e) {
println("Controller: " +
e.getResourceInfo().getResourceMethod());
}
}
Events Example

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#Devoxx #JSR371
Summary

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Project Page
https://java.net/projects/mvc-spec
Mailing List
[email protected]
Reference Implementation
https://ozark.java.net

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#Devoxx #JSR371
JSR 371 - Test Drive

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How about Real World?

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Real World - Key Questions
Common Problems Solved for Real World?
On Par with comparable Servlet-based Frameworks?

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#Devoxx #JSR371
Comparable Frameworks
Spring MVC
around since 2005
“Real World” since 2008 (Spring 2.5 onward)
today’s leader in Action-Land
Struts 2
around since 2004 (WebWork 2)
“Real World” since 2007 (Struts 2.0.9 onward)
still widely adopted

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#Devoxx #JSR371
Comparable Frameworks
Spring MVC
around since 2005
“Real World” since 2008 (Spring 2.5 onward)
today’s leader in Action-Land
Struts 2
around since 2004 (WebWork 2)
“Real World” since 2007 (Struts 2.0.9 onward)
still widely adopted
3 Years till getting Real!

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#Devoxx #JSR371

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#Devoxx #JSR371
Let’s relax a bit…
JSR 371: „Standing on the Shoulder of Giants“
JAX-RS / Jersey
CDI
Bean Validation
Interceptors
Facelets, Thymeleaf, Freemarker, Velocity
Adds on Top
Lightweight Top Layer
Extension Points

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#Devoxx #JSR371
So - what are these
“Common Problems“?

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#Devoxx #JSR371
“Hello MVC”
is not enough!

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#Devoxx #JSR371
Common Real World Needs
Scoped DI
Controller Decoupling
Controller Testability
View Technology Flexibility
VDL Expressiveness
i18n / l10n
Form Binding
Type Conversion
Declarative Validation
Message Passing to View
Post-Redirect-Get
File Upload
UI Controls and Theming
AJAX Support
Decorator Support
Cross Cutting Concerns

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#Devoxx #JSR371
Scoped Dependency Injection
Spring MVC
Spring DI
Struts 2
Supported
Containers
Supported Scopes EJB Support
Spring MVC Spring DI
Application, Session,
Request, Redirect,
Custom
Yes (Adapter
Framework)
Struts 2
Spring DI, Guice,
CDI
Application, Session,
Request, Redirect,
Custom
Yes (CDI)
JSR 371 / Ozark CDI
Application,
Session, Request,
Redirect, Custom
Yes

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#Devoxx #JSR371
Controller Decoupling
Spring MVC
Spring DI
Struts 2
Controllers as
POJOs
Coupling to
Servlet API
required
Coupling to
Servlet API
supported
Model
Abstraction
Spring MVC Yes No Yes
Model
Container,
Return value
Struts 2 Yes No Yes
Controller
Instance, Value
Stack
JSR 371 / Ozark Yes No Yes
Scoped CDI
Beans, Model
Container

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#Devoxx #JSR371
Controller Testing Support
Spring MVC
Spring DI
Struts 2
Unit Testing Mocking Support
Integration
Test Framework
Spring MVC Easy Easy Spring Test MVC
Struts 2 Easy Easy
Struts 2 Test
Framework
JSR 371 / Ozark Easy Easy
No / presumably
Jersey Test
Framework

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#Devoxx #JSR371
Supported View Technologies
Spring MVC
Spring DI
Struts 2
JSP Templating
DHTML
Integration
Others
Spring MVC Yes
Thymeleaf,
Freemarker,
Velocity, GSP
Various 3rd
Party
Contributions
JSON, XML,
JasperReports
Struts 2 Yes
Freemarker,
Velocity,
Thymeleaf
jQuery,
Bootstrap, YUI
AngularJS
JSON, XML,
JasperReports
JSR 371 / Ozark Yes
Facelets,
Freemarker,
Velocity,
Thymeleaf
Handlebars,
Mustache
JSON + XML
(JAX-RS),
AsciiDoc

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#Devoxx #JSR371
Real Code

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#Devoxx #JSR371
Wrap-up: State of MVC
Lightweight Layer on Top of well established Technologies
Easy to extend
Addresses most Common Needs
Some Gaps and Glitches
most can easily addressed by Implementations and Extensions
some might be gone in the ﬁnal Speciﬁcations

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#Devoxx #JSR371
Q & A

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MVC 1.0 - by Example @ Devoxx Belgium 2015

MVC 1.0 - by Example @ Devoxx Belgium 2015

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