Reduce to the Max: Lightweight Java EE

Java

Reduce to the MaxLightway Enterprise Java

Lars Röwekamp | open knowledge GmbH

@mobileLarson@_openknowledge

„Weniger ist mehr!“

„Java EE ermöglicht - dank EE Web

Profile - extrem elegante und

l e i c h t g e w i c h t i g e E n t e r p r i s e

Anwendungen“

Was sie mitnehmen sollten ...JSF & CDI Lightway Java EE

Der KlassikerJSF & CDI Lightway Java EE


TX

Ok, wo liegt das Problem?

Heterogene Lösungen


eigene DI, Validierung, LifeCycle



Technology drivesBusiness


TX

UC: „User“ anzeigen/ändern


TX

Einen JSF ManagedBean

Controller, bitte.

Und für mich einen EJB Service.

Entity X mit ID Y,wenn möglich.

UC: „User“ anzeigen/ändern


TX

Einen JSF ManagedBean

Controller, bitte.

Und für mich einen EJB Service.

Entity X mit ID Y,wenn möglich.

Hey, ich will doch nur den Current User!


@ManagedBean(name=“userController“) @SessionScoped public class UserControllerMB implements Serializable {

private User user; // plus getter and setter

@ManagedProperty(value=“#{authenticationController}“) private authControllerMB AuthenticationController;

@EJB private UserService userService

@EJB private MailService mailService

... // some more services needed public String create() { .. }

public String askForDeleteConfirmation() { ... }

public String deleteAfterConfirmation() { ... }

}










}

Layer Solution










}

String basiertes IoC

Layer Solution










}


Infrastrutur Injection

Layer Solution










}



Technology Injection

Layer Solution










}



String basierte Navi

Technology Injection

Layer Solution



...

public String create() { if (user.getUsername() == user.getPassword()) { ... // create faces messages return USERNAME_SHOULD_NOT_EQUAL_PASSSWORD; // createUser.xhtml } else if (userService.checkForFreeUsername(user.getUsername())) { userService.create(user); mailService.sendWelcomeMail(user); SystemUser loggedInUser = authenticationController.getLoggedInUser(); if (Role.ROLE_TRAINEE.equals(loggedInUser.getRole()) { trackingService.trackAction(TrackAction.USER_CREATED, user); } return “USER_CREATED“; // or userOverview.xhtml } else { ... // create faces messages return “DUPLICATE_USERNAME“; // or createUser.xhtml } } }



...


Monster UseCase



...


Monster UseCase

Cross Validation


@ManagedBean(name=“userController“) @SessionScoped public class UserControllerMB implements Serializable{

private User user;

... public String askForDeleteConfirmation(User userToDelete) { user = userToDelete; return “USER_READY_FOR_DELETE“; // userDeleteConfirmation.xhtml }

public String deleteAfterConfirmation() { userService.delete(user); ... // do some more stuff, e.g. sending an email, tracking, ... user = null; return “USER_DELETED“; // userSuccessfulDeleted.xhtml }

}


@ManagedBean(name=“userController“) @SessionScoped public class UserControllerMB implements Serializable{

private User user;



}

Session statt „Wizard“

Scope Mismatch

Java

U are here!

Java

„We want a typesafe and modern lightway

Enterprise Achritecture.“

Refactoringis needed

Der Klassiker - revistedJSF & CDI Lightway Java EE

Java

„Get ride of all the JSF specific Managed

Beans and Scopes.“

RefactoringStep 1

Refactoring - Step 1 JSF & CDI Lightway Java EE

@javax.faces.bean.ManagedBean(name=“userController“) @javax.faces.bean.SessionScoped public class UserControllerMB implements Serializable {


@javax.faces.ManagedProperty(value=“#{authenticationController}“) private authControllerMB AuthenticationController;



... }


@javax.inject.Named(“userController“) @javax.enterprise.context.SessionScoped public class UserControllerMB implements Serializable {


@javax.inject.Inject private authControllerMB AuthenticationController;



... }


@javax.inject.Named(“userController“) @javax.enterprise.context.SessionScoped public class UserControllerMB implements Serializable {


@javax.inject.Inject private authControllerMB AuthenticationController;

@javax.inject.Inject private UserService userService

@javax.inject.Inject private MailService mailService

... }


@SessionScopedclass MyBeanA

Proxy forclass MyModel

@Inject

@RequestScopedclass MyModel

Injection Target Contextual Reference Contextual Instance

businessMethod() Lookup or create

return

businessMethod()

returnreturn

Spezialfall

Java

„Use Business Injection instead of

Infrastructure Injection.“

RefactoringStep 2


@Named(“userController“) @SessionScoped public class UserControllerMB implements Serializable {

@Inject private AuthControllerMB authenticationController;



... }



@Inject private SystemUser loggedInUser;



... }



@Inject private SystemUser loggedInUser;



... }

@Current


@SessionScoped public class AuthenticationController

implements Serializable {

private SystemUser authenticatedUser;

public String authenticate() { ... }

public SystemUser getAuthenticatedUser() { return authenticatedUser; }

}







}

@Produces @Current







}

@Produces @Current

@Inject @Current SystemUser







}

@Produces @Current


@Named(“loggedInUser“)

#{loggedInUser}







}

@Produces @Current


@Named(“loggedInUser“)

#{loggedInUser}

@RequestScoped


@Qualifier@Target({FIELD, PARAMETER, METHOD, TYPE})@Retention(RUNTIME)public @interface Current { }


@Qualifier@Target({FIELD, PARAMETER, METHOD, TYPE})@Retention(RUNTIME)public @interface Current { }

Self-made Qualifier

Java

„Split Monster Use Case into its

logical & modular Parts.“

RefactoringStep 3



...

public String create() { if (user.getUsername() == user.getPassword()) { ... // create faces messages return USERNAME_SHOULD_NOT_EQUAL_PASSSWORD; // createUser.xhtml } else if (userService.checkForFreeUsername(user.getUsername())) { userService.create(user); mailService.sendWelcomeMail(user); User loggedInUser = authenticationController.getLoggedInUser(); if (Role.ROLE_TRAINEE.equals(loggedInUser.getRole()) { trackingService.trackAction(TrackAction.USER_CREATED, user); } return “USER_CREATED“; // or userOverview.xhtml } else { ... // create faces messages return “DUPLICATE_USERNAME“; // or createUser.xhtml } } }

JSF & CDI Lightway Java EE

@Named(“userController“) @SessionScoped public class UserController implements Serializable {

...

private User user; ... public String create() { userService.create(user); // main use case ... return “USER_CREATED“; // navigation } }

Refactoring - Step 3



@Inject @Created Event<User> userCreatedEventSource;

private User user; ... public String create() { userService.create(user); // main use case userCreatedEventSource.fire(user); // sub use cases return “USER_CREATED“; // navigation } }




@Inject @Created Event<User> userCreatedEventSource;

private User user; ... public String create() { userService.create(user); // main use case userCreatedEventSource.fire(user); // sub use cases return “USER_CREATED“; // navigation } }

Refactoring - Step 3 Loosly coupled

via CDI Event


@ApplicationScoped public class MailService {

public void sendWelcomeMail(@Observes @Created User createdUser) {

... // do some work with createdUser }

... }


Event Consumer I


@ApplicationScoped public class TrackingService {

@Inject @Current User loggedInUser;

public void trackUserCreated(@Observes @Created User newUser) { if (User.ROLE_TRAINEE.equals(loggedInUser.getRole()) { this.trackAction(TrackAction.USER_CREATED, newUser); } } ... }


Event Consumer II


@ApplicationScoped public class TrackingService {

@Inject @Current User loggedInUser;

public void trackUserCreated(@Observes(during == AFTER_SUCCESS) @Created User newUser) { if (User.ROLE_TRAINEE.equals(loggedInUser.getRole()) { this.trackAction(TrackAction.USER_CREATED, newUser); } } ... }


Event Consumer II


@ApplicationScoped public class GlobalCache {

public void insertIntoCache(@Observes(receice == IF_EXISTS, during == AFTER_SUCCESS) @Created User newUser) { ... // do some work } ... public void deleteFromCache(@Observes(receice == IF_EXISTS, during == AFTER_SUCCESS) @Deleted User deletedUser) { ... // do some other work }

}


Event Consumer II

Java

„Validate once and only once -

not once per layer.“

RefactoringStep 4



*many thanks to irian.at



<html xmlns=“http://www.w3.org/1999/xhtml” ...

<h:form id=“createUserForm”> <h:outputLabel for=“firstName“ value=“Vorname:“ <h:inputText id=“firstName“ value=“#{userController.user.firstName}“> <f:validateRequired /> <f:validateLenght minimum=“8“ /> </h:inputText> ... </h:form> ...

<h:messages globalOnly=“true” /></html>

http://www.w3.org/1999/xhtml


JSF & CDI

Und wo ist das Problem?

‣Cross Side Validation‣Cross Layer Validation‣Cross Component Validation

Migration GuideRefactoring - Step 4

JSF & CDI

Cross Side/Layer Validation

‣ Bean Validation 1.0 (JSR 303)‣ @nnotation basiert

‣ Validierung des Domain Models‣ JSF 2 supported‣ eigene Constraints möglich


JSF & CDI Migration Guide


public class User {

@Birthday private Date dateOfBirth; @Min(value = 0) private Integer children;

@NotNull private String firstName; @NotNull private String lastName;

...}

Validator Interface

JSF & CDI

Cross Component Validation

‣ JSF Events ermöglichen das gezielte Aufrufen einer via <f:event> Tag angegebenen Methode als direkte Reaktion auf ein Component Event

‣ JSF Events sind u.a. ‣ preValidate‣ postValidate




public class ChangePasswordBean { ...

public void validate(ComonentSystemEvent event) { UIForm form = (UIForm)e.getComponent(); UIInput oldPwdInput = (UIInput)form.findComponent(“oldPwd”); String oldPwd = (String)oldPwdInput.value(); ... if (oldPwd.equals(newPwd)) { // 1. set faces error messgage // 2. render response ... } }}

Java

„Make Transactions where you want - not

where Technology.“

RefactoringStep 5


TX




...

public String create() { userService.create(user); // main use case userCreatedEventSource.fire(user); // Created Event return “USER_CREATED“; // Navigation } }




...



Transactional Use Case



...



Transactional Use Case

* JTA 1.2 oder DeltaSpike oder Self-Made

@Transactional


@InterceptorBinding @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.METHOD, ElementType.TYPE}) public @interface Transactional { @NonBinding public TransactionalType value() ! default TransactionalType.REQUIRED; }



@InterceptorBinding @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.METHOD, ElementType.TYPE}) public @interface Transactional { @NonBinding public TransactionalType value() ! default TransactionalType.REQUIRED; }


Transactional Annotation


@Transactional @Interceptor public class TransactionInterceptor {

@Inject private UserTransaction utx;

@AroundInvoke public Object applyTransaction(InvocationContext ic) throws Throwable {

... // implement utx.begin() ic.proceed(); // call original method ... // implement utx.commit()

} }


* XML Konfiguration


@Transactional @Interceptor public class TransactionInterceptor {

@Inject private UserTransaction utx;

@AroundInvoke public Object applyTransaction(InvocationContext ic) throws Throwable {

... // implement utx.begin() ic.proceed(); // call original method ... // implement utx.commit()

} }


* XML Konfiguration

Transactional Interceptor

Java

„Use corresponding Scopes - not too short

and not too long“

RefactoringStep 6



private User user;



}


@RequestScopedclass MyBeanA

@ConversationSopedclass MyWizard

@Inject Conversation conv; // inside „start“ Methode conv.begin();

// inside „end“ Methode conv.end();

@RequestScopedclass MyBeanB

@Inject

@Inject


@Named(“userController“) @ConversationScoped public class UserControllerMB implements Serializable {

private User user;

@Inject Conversation conversation; ... public String askForDeleteConfirmation(User userToDelete) { conversation.begin(); user = userToDelete; return “USER_READY_FOR_DELETE“; // userDeleteConfirmation.xhtml }


}


@Named(“userController“) @ConversationScoped public class UserControllerMB implements Serializable{

private User user;

@Inject Conversation conversation; ... public String askForDeleteConfirmation(User userToDelete) { ... }

public String deleteAfterConfirmation() { conversation.end(); userService.delete(user); ... // do some more stuff, e.g. sending an email, tracking, ... user = null; return “USER_DELETED“; // or userSuccessfulDeleted.xhtml }

}

Java

„The Spec is kind of slow when it

comes to evolution.“

The MissingPieces

EE Web Profile - Missing PiecesJSF & CDI Lightway Java EE

Bessere Conversationen

Built-in Transaktionen

weitere Scopes

typesafe Navigation

und vieles mehr ...

EE Web Profile - Missing PiecesJSF & CDI Lightway Java EE

JSF & CDI

Lightway Enterprise Java

‣mit CDI

‣ typensicher ‣ schichtenneutral‣ fachliche und technologische Injection ‣ eventgetriebene Entwicklung

FazitMigration Guide

Java

Reduce to the MaxLightway Enterprise Java

Lars Röwekamp | open knowledge GmbH

@mobileLarson@_openknowledge

Reduce to the Max: Lightweight Java EE

Technology

Transcript of Reduce to the Max: Lightweight Java EE