MVC 1.0 - by Example @ GIDS 2016

Model-view-controller, or MVC for short, is a common pattern in web frameworks. MVC frameworks can be categorized as action-based or component-based. In a component-based framework, the HTTP requests are grouped and typically handled by framework components with little or no interaction with application code. In an action-based framework, on the other hand, the HTTP requests are routed to controllers and turned into actions by application code.

The Java EE platform does not currently have support for action based MVC, but this is about to change. MVC 1.0, as specified by JSR 371, is targeted for the upcoming Java EE 8 release.

This session provides an introduction to the action-based MVC 1.0 API and will include lots of code samples and tips to where to get started using this awesome technology.

Transcript

1. MVC 1.0 - by Example
   Ivar Grimstad
   Principal Consultant, Cybercom Sweden
   JCP Expert Group Member (JSRs 368, 371, 375)
   

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2. @ivar_grimstad
   https://github.com/ivargrimstad
   https://www.linkedin.com/in/ivargrimstad
   http://lanyrd.com/profile/ivargrimstad/
   

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3. MVC
   

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4. Why?
   

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5. https://java.net/downloads/javaee-spec/JavaEE8_Community_Survey_Results.pdf
   

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6. http://glassfish.org/survey
   

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7. JSR 371 - MVC 1.0
   

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8. JSR 371 Expert Group
   

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9. Action-based MVC
   

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10. Controller
    Model View
    Request
    Update
    Update
    Get
    

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11. Controller
    Model View
    Request
    Update
    Update
    Get
    Component-based MVC
    

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12. Controller
    Model View
    Request
    Update
    Update
    Get
    Action-based MVC
    

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13. 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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14. Existing Java EE
    Technologies
    

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15. Key Decisions
    

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16. Key Decisions
    

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17. Build MVC 1.0 on top of
    JAX-RS
    

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18. Controllers
    

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19. public class HelloController {
    }
    Controller
    

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20. @Path(“hello”)
    public class HelloController {
    }
    Controller
    

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21. @Controller
    @Path(“hello”)
    public class HelloController {
    }
    Controller
    

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22. Views
    

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23. @Controller
    @Path(“hello”)
    public class HelloController {
    }
    View
    

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24. @Controller
    @Path(“hello”)
    public class HelloController {
    @GET
    public String hello() {
    return “hello.jsp”;
    }
    }
    View
    

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25. @Controller
    @Path(“hello”)
    public class HelloController {
    @GET
    public Viewable hello() {
    return new Viewable(“hello.jsp”);
    }
    }
    View
    

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26. @Controller
    @Path(“hello”)
    public class HelloController {
    @GET
    public Response hello() {
    return Response.status(OK).entity(“hello.jsp”).build();
    }
    }
    View
    

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27. @Controller
    @Path(“hello”)
    public class HelloController {
    @View(“hello.jsp”)
    @GET
    public void hello() {
    }
    }
    View
    

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28. @View(“hello.jsp”)
    @Controller
    @Path(“hello”)
    public class HelloController {
    @GET
    public void hello() {
    }
    }
    View
    

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29. Models
    

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

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31. @View(“hello.jsp”)
    @Controller
    @Path(“hello”)
    public class HelloController {
    @GET
    public void hello() {
    }
    }
    Model
    

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32. @View(“hello.jsp”)
    @Controller
    @Path(“hello”)
    public class HelloController {
    @Inject
    private Greeting greeting;
    @GET
    public void hello() {
    greeting.setMessage(“Hello GIDS 2016!”);
    }
    }
    Model
    

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33. <%@page contentType=“text/html" pageEncoding="UTF-8"%>
    
    
    
    MVC 1.0 Hello Demo
    
    
    Hello ${greeting.message}
    
    
    Model
    

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34. @View(“hello.jsp”)
    @Controller
    @Path(“hello”)
    public class HelloController {
    @GET
    public void hello() {
    }
    }
    Model
    

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35. @View(“hello.jsp”)
    @Controller
    @Path(“hello”)
    public class HelloController {
    @Inject
    private Models model;
    @GET
    public void hello() {
    model.put(“message”, “Hello GIDS 2016!”);
    }
    }
    Model
    

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36. <%@page contentType=“text/html" pageEncoding="UTF-8"%>
    
    
    
    MVC 1.0 Hello Demo
    
    
    Hello ${message}
    
    
    Model
    

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37. Validation
    

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

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39. public class FormViolationMapper implements
    ExceptionMapper
    {
    public Response toResponse(ConstraintViolationException e) {
    // process violations …
    return Response.status(BAD_REQUEST)
    .entity(“error.jsp”).build();
    }
    }
    Validation
    

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40. @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();
    }
    }
    Allows for MVC Error Handling
    Validation
    

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41. Security
    

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

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43. <%@page contentType=“text/html" pageEncoding="UTF-8"%>
    
    
    
    MVC 1.0 Hello Demo
    
    
    charset="utf-8">
    
    value="${mvc.csrf.token}"/>
    
    
    
    Cross Site Request Forgery
    

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44. Scopes
    

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45. @Named(“greeting”)
    @RedirectScoped
    public class Greeting {
    private String message;
    public void setMessage(String message) {
    this.message = message;
    }
    public void getMessage() { return message; }
    }
    @RedirectScoped
    

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46. @Controller
    public class HelloController {
    @Inject
    private Greeting greeting;
    @POST
    @Path(“from”)
    public String hello() {
    greeting.setMessage(“Hello GIDS 2016!”);
    return “redirect:to“;
    }
    }
    @RedirectScoped
    @RequestScoped
    @RedirectScoped
    

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47. @Controller
    public class HelloController {
    @Inject
    private Greeting greeting;
    @POST
    @Path(“to”)
    public String hello() {
    return “here.jsp“;
    }
    }
    Same Bean
    @RedirectScoped
    

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48. Tired of slides?
    

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49. Show me the real
    CODE !
    

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50. Model
    ReservationCtl
    Update
    confirmation
    reservation
    OK
    Browser
    POST
    

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51. Model
    ReservationCtl
    Access
    Update
    ConfirmationC
    tl
    GET
    confirmation
    reservation
    OK
    Redirect
    Browser
    POST
    

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52. View Engines
    

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53. Bring Your Own View
    Engine
    

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54. public interface ViewEngine {
    boolean supports(String view);
    void processView(ViewEngineContext context)
    throws ViewEngineException;
    }
    ViewEngine
    

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55. @Priority(OUTRAGEOSLY_HIGH)

    @ApplicationScoped

    public class FreemarkerViewEngine extends ViewEngineBase {
    …
    }
    ViewEngine
    

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56. Events
    

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57. BeforeControllerEvent
    AfterControllerEvent
    BeforeProcessViewEvent
    AfterProcessViewEvent
    ControllerRedirectEvent
    

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58. @ApplicationScoped
    public class EventObserver {
    void onBeforeController(@Observes BeforeControllerEvent e) {
    }
    void onAfterController(@Observes AfterControllerEvent e) {
    }
    }
    Events Example
    

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59. Tool Support
    

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60. JPA Modeler
    http://jpamodeler.github.io/
    Gaurav Gupta
    @jGauravGupta
    

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61. Summary
    

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62. Action-based MVC
    

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63. Existing Java EE
    Technologies
    

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64. Build MVC 1.0 on top of
    JAX-RS
    

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65. Project Page
    https://java.net/projects/mvc-spec
    GitHub
    https://github.com/mvc-spec
    Reference Implementation
    https://ozark.java.net
    

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66. Samples
    https://github.com/ivargrimstad/mvc-samples
    Blog
    http://www.agilejava.eu/
    

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67. @ivar_grimstad
    @greatindiandev #GIDS2016
    cybercom.com
    

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