Vorschau auf Webanwendungen mit MVC 1.0 und Eclipse Krazo

Seit Jahren wird die Java Enterprise Welt von zwei Frontends beherrscht: Java Server Pages (JSP) und Java Server Faces (JSF). Beide Technologien sind mittlerweile sehr alt und können die Anforderungen an moderne und verteilte Systeme kaum erfüllen. Mit der MVC API 1.0 soll dieses Problem gelöst werden.

Der Vortrag geht zuerst auf die Grundlagen der API und ihren Platz in der Java Enterprise Welt ein. Danach wird anhand eines durchgängigen Beispiels gezeigt, wie MVC Ressourcen angelegt und verschiedene Use-Cases damit implementiert werden.

Transcript

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3. FacesServlet
   

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6. •
   •
   •
   •
   

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7. •
   •
   • JSP und Facelets müssen
   grundsätzlich unterstützt werden
   • diverse Krazo-Extensions existieren
   schon (eingeschränkte Features)
   •
   •
   •
   

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9. plugins {
   id 'java'
   id 'war'
   }
   repositories {
   jcenter()
   mavenCentral()
   maven {
   url "https://oss.sonatype.org/content/repositories/snapshots"
   }
   }
   dependencies {
   //…
   implementation 'javax.mvc:javax.mvc-api:1.0-pfd‘
   implementation 'org.eclipse.krazo:krazo-resteasy:1.0.0-SNAPSHOT‘
   // implementation 'org.eclipse.krazo.ext:krazo-thymeleaf:1.0.0-SNAPSHOT'
   providedCompile 'javax:javaee-api:8.0.1‘
   //…
   }
   

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11. import javax.ws.rs.ApplicationPath;
    import javax.ws.rs.core.Application;
    @ApplicationPath("/mvc")
    public class App extends Application {
    }
    

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12. 
    
    
    
    Hello World
    
    
    Hello World!
    
    
    import javax.mvc.Controller;
    import javax.ws.rs.GET;
    import javax.ws.rs.Path;
    @Path("hello")
    @Controller
    public class
    HelloWorldController {
    @GET
    public String sayHello() {
    return "hello.jsp";
    }
    }
    

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15. @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @Inject
    private Models models;
    @GET
    public String index() {
    final var bookings = bookingService.getAllBookings();
    models.put("bookings", bookings);
    return "index.jsp";
    }
    // ...
    

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16. @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @Inject
    private Models models;
    @GET
    public String showIndex() {
    // ...
    models.put("bookings", bookings);
    return "index.jsp";
    }
    // ...
    }
    
    
    ${booking.bookingNumber}
    ${booking.name}
    …
    
    

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17. @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @Inject
    private Models models;
    @GET
    public String showIndex() {
    final var bookings =
    bookingService.getAllBookings();
    models.put("bookings", bookings);
    return "index.jsp";
    }
    // ...
    }
    

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18. @Inject
    private Models models;
    
    
    ${booking.bookingNumber}
    ${booking.name}
    …
    
    @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @Inject
    private Models models;
    @GET
    public String showIndex() {
    // ...
    return "index.jsp";
    }
    // ...
    }
    

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20. @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @GET
    @Path("/{bookingNumber}")
    public Response showDetailsOfBooking(@PathParam("bookingNumber") final UUID bookingNumber) {
    final var booking = bookingService.findBookingForBookingNumber(bookingNumber);
    if (booking.isPresent()) {
    models.put("booking", booking.get());
    return Response.ok("details.jsp").build();
    } else {
    models.put("bookingNumber", bookingNumber);
    return Response.status(Response.Status.NOT_FOUND).entity("404.jsp").build();
    }
    }
    // ...
    

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21. @GET
    @Path("/{bookingNumber}")
    public Response showDetailsOfBooking(
    @PathParam("bookingNumber") final UUID bookingNumber) {
    // ...
    if (booking.isPresent()) {
    models.put("booking", booking.get());
    return Response.ok("details.jsp").build();
    } else {
    // ...
    }
    }
    

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22. @GET
    @Path("/{bookingNumber}")
    public Response showDetailsOfBooking(
    @PathParam("bookingNumber") final UUID bookingNumber) {
    // ...
    if (booking.isPresent()) {
    // ...
    } else {
    models.put("bookingNumber", bookingNumber);
    return Response
    .status(Response.Status.NOT_FOUND)
    .entity("404.jsp")
    .build();
    }
    }
    

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24. href="/bookings/${booking.bookingNumber}">
    Details
    
    

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25. href="/bookings/${booking.bookingNumber}">
    Details
    
    

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26. href="/bookings/${booking.bookingNumber}">
    Details
    
    

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27. href="${mvc.uriBuilder('BookingController#showDetailsOfBooking').build(booking.bookingNumber)}">
    Details
    
    

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28. href="${mvc.uriBuilder('BookingController#showDetailsOfBooking').build(booking.bookingNumber)}">
    Details
    
    @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @GET
    @Path("/{bookingNumber}")
    public String showDetailsOfBooking(@PathParam("bookingNumber") final UUID bookingNumber) {
    // ...
    }
    // ...
    

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29. →
    
    Details
    
    

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30. href="${mvc.uriBuilder('showBookingDetails').build(booking.bookingNumber)}">Details
    
    @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @GET
    @Path("/{bookingNumber}")
    @UriRef("showBookingDetails")
    public String showDetailsOfBooking(@PathParam("bookingNumber") final UUID bookingNumber) {
    // ...
    }
    // ...
    

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31. →
    
    Details
    
    

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33. @Path("/bookings")
    @Controller
    public class BookingController {
    // ...
    @GET
    @Path("/new")
    public String showNewBookingForm() {
    return "form.jsp";
    }
    // ...
    }
    

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34. 
    
    
    Name
    
    
    
    
    
    Save
    
    
    
    

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35. // ...
    @Inject private BindingResult bindingResult;
    @POST
    public String createNewBooking(@MvcBinding @FormParam("name")
    @NotBlank @Size(min = 5, max = 255) final String name) {
    if (bindingResult.isFailed()) {
    models.put("errors", new ArrayList<>(bindingResult.getAllErrors()));
    return "form.jsp";
    }
    final var booking = bookingService.createNewBooking(name);
    return "redirect:/bookings/" + booking.getBookingNumber();
    }
    // ...
    placeholder="Name of booking" required>
    

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36. 
    
    
    ${msg.get("form.label.name")}
    
    
    
    
    
    
    
    
    ${error.getParamName()}: ${error.getMessage()}
    
    
    
    
    
    
    
    ${msg.get("form.btn.save")}
    
    
    
    

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38. // ...
    @DELETE
    @Path("/{bookingNumber}")
    public String cancelBooking(@PathParam("bookingNumber") final UUID bookingNumber) {
    final var isCancelled = bookingService.cancelBooking(bookingNumber);
    return isCancelled ? "redirect:/bookings" : "404.jsp";
    }
    // ...
    

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40. action="${mvc.uriBuilder('BookingController#cancelBooking').build(booking.bookingNumber)}"
    onsubmit="return confirm('Do you really want to cancel the booking?');">
    
    Cancel
    
    

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42. /**
    * Locale resolvers are used to determine the locale of the current request and are
    * discovered using CDI.
    *
    *
    * …
    */
    public interface LocaleResolver {
    /**
    * Resolve the locale of the current request given a {@linkLocaleResolverContext}.
    *
    * …
    *
    * @param context the context needed for processing.
    * @return The resolved locale or null.
    */
    Locale resolveLocale(LocaleResolverContext context);
    }
    

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43. /**
    * Locale resolvers are used to determine the locale of the current request and are
    * discovered using CDI.
    *
    *
    * …
    */
    public interface LocaleResolver {
    /**
    * Resolve the locale of the current request given a {@linkLocaleResolverContext}.
    *
    * …
    *
    * @param context the context needed for processing.
    * @return The resolved locale or null.
    */
    Locale resolveLocale(LocaleResolverContext context);
    }
    org.eclipse.krazo.locale.LocaleResolverChain
    MvcContext
    

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44. messages
    //messages.properties
    …
    #Index Page
    page.title=My awesome application
    #Hello World
    hello.world=Hello World!
    //messages_fr.properties
    #Hello World
    hello.world=Bonjour le monde!
    //messages_de.properties
    #Hello World
    hello.world=Hallo Welt!
    

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45. @RequestScoped
    @Named("msg")
    public class Messages {
    @Inject
    private MvcContext mvcContext;
    public final String get(final String key) {
    LOGGER.info(String.format("Getting message '%s' for locale '%s'", key,
    mvcContext.getLocale()));
    final var bundle = ResourceBundle.getBundle("messages", mvcContext.getLocale());
    return bundle.containsKey(key) ? bundle.getString(key) : formatUnknownKey(key);
    }
    private static String formatUnknownKey(final String key) {
    return String.format("???%s???", key);
    }
    }
    

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46. <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    
    
    
    ${msg.get("page.title")}
    
    
    ${msg.get("hello.world")}
    
    
    

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47. //messages.properties
    
    
    
    
    My awesome application
    
    
    
    
    Hello World!
    
    
    
    //messages_fr.properties
    
    
    
    
    My awesome application
    
    
    
    
    Bonjour le monde!
    
    
    
    //messages_de.properties
    
    
    
    
    My awesome application
    
    
    
    
    Hallo Welt!
    
    
    
    

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48. ☺
    - Dokumentation für TCK erstellen
    - Lizenzrechtliche Prüfungen durch Oracle bei Krazo
    

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50. - Cookbook: https://www.mvc-spec.org/learn/cookbook/
    

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