Die Bordmittel von Java EE ermöglichen Architekturen, von denen man vor wenigen Jahren nur träumen durfte. Nahezu losgelöst von technologischen und schichtenbedingten Restriktionen kommen dank CDI und Co. völlig neue Patterns zum Tragen. Im Gegenzug dazu kann auf „lieb gewonnene“ Workarounds verzichtet werden. Die Session gibt einen Einblick in die vielfältigen Möglichkeiten, die einem der aktuelle Java-Enterprise-Standard bietet, und möchte so zu neuen Denkmustern im Java-EE-Architekturdesign anregen.

1. #WISSENTEILEN
No-Tier Applications
Lars Röwekamp | CIO New Technologies
#WISSENTEILEN
@mobileLarson
@_openknowledge

2. #WISSENTEILEN
ÜBER OPEN KNOWLEDGE
Branchenneutrale Softwareentwicklung & IT-Beratung

3. #WISSENTEILEN
ÜBER MICH
Wer bin ich - und wenn ja, wie viele?
• CIO New Technologies
• Enterprise & Mobile
• Autor, Speaker, Coach & Mentor
• Snowboard & MTB Enthusiast
Lars Röwekamp (a.k.a. @mobileLarson)
LR

4. #WISSENTEILEN
„May I submit my billing info to your
merchant account via your payment
gateway?“

5. #WISSENTEILEN
Die gute „alte“ Schichtenarchitektur
Fachliche Injection
Fachliche Transaktionen
Fachliche Scopes
Fachliche Methoden
No-Tier Applications

6. #WISSENTEILEN
Die gute „alte“
Schichtenarchitektur
(Quelle: https://www.bettycrocker.com/recipes/rainbow-layer-cake/)

7. #WISSENTEILEN
Die Use Cases
Call Center Anwendung
• Kunde neu erfassen und speichern
• Kunde löschen mit Bestätigung

8. #WISSENTEILEN
„Create“

9. #WISSENTEILEN
Der Use Case
UC-001: „create Customer“
• Kunde neu erfassen und speichern
• Call Center Agent als Audit-Info speichern
• Begrüßungs-Mail an Neukunden versenden

10. #WISSENTEILEN
Der Use Case
UC-001: „create Customer“
• Kunde neu erfassen und speichern
• Call Center Agent als Audit-Info speichern
• btw: wenn CC Agent Trainee, dann Tracing
• Begrüßungs-Mail an Neukunden versenden
• btw: nur wenn Kunde eMail hinterlegt hat

11. #WISSENTEILEN
Der Use Case
UC-001: „create Customer“
• (JSF) View ruft UI Controller via U-EL
• UI Controller ruft CustomerService EJB/CDI
• UI Controller ruft MailService EJB/CDI

12. #WISSENTEILEN
„Create v2“

13. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private CustomerService customerService;
@Inject
private MailService mailService;
private Customer customer;
public Outcome createCustomer() {
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
…
}
Und was ist mit dem
Call Center Agent?

14. #WISSENTEILEN
Der Use Case
UC-001: „create Customer“
• (JSF) View ruft UI Controller via U-EL
• UI Controller ruft CustomerService EJB/CDI
• UI Controller ruft MailService EJB/CDI
• UI Controller ruft AuthenticationController

15. #WISSENTEILEN
„Create v3“

16. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private AuthenticationController authController;
...
public Outcome createCustomer() {
CallCenterAgent callCenterAgent = authController.getAuthenticatedUser();
customer.updateAuditInformation(callCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}
Ist der Call Center
Agent ein Trainee?
Hat der Kunde
eine eMail?

17. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerBean {
@Inject
private CustomerService customerService;
@Inject
private MailService mailService;
@Inject
private TrackService trackService;
@Inject
private AuthenticationController authenController;
private Customer customer;
public Outcome createCustomer() {
// get logged in call center agent for auditing
CrmUser callCenterAgent = authController.getAuthenticatedUser();
// set audit information
currentCustomer.updateAuditInformation(callCenterAgent);
// track call center activity, if trainee
if (callCenterAgent.isTrainee()) {
TrackAction trackAction = TrackAction.ADD_CUSTOMER;
List<TrackParameter> trackParameters = new ArrayList<TrackParameter>();
TrackParameter trackParameter = new TrackParameter(TrackParameterKey.CALL_CENTER_AGENT, callCenterAgent);
trackParameters.add(trackParameter);
trackService.track(trackAction, trackParameters);
}
// add customer to db via customer service
customerService.createCustomer(customer);
// send welcome mail, if customer has an email address
if (customer.getEmail() != null
&& customer.getEmail().length() > 0) {
mailService.sendMail("Welcome", "Welcome to jeeCRM“, customer.getEmail());
}
return Outcome.SUCCESS;
}
}

18. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private AuthenticationController authController;
...
public Outcome createCustomer() {
CallCenterAgent callCenterAgent = authController.getAuthenticatedUser();
customer.updateAuditInformation(callCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}
Wie steht‘s eigentlich
mit Transaktionen?

19. #WISSENTEILEN
Der Use Case
UC-001: „create Customer“
• (JSF) View ruft UI Controller via U-EL
• UI Controller ruft AuthenticationController
• UI Controller ruft CustomerFacade EJB
• Delegate EJB ruft CustomerService EJB/CDI
• Delegate EJB ruft MailService EJB/CDI

20. #WISSENTEILEN
„Create v4“

21. #WISSENTEILEN
„Create v4“
TX

22. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@EJB
private CustomerFacade customerFacade;
@Inject
private AuthenticationController authController;
...
public Outcome createCustomer() {
CallCenterAgent callCenterAgent = authController.getAuthenticatedUser();
customerFacade.createCustomer(customer, callCenterAgent);
return Outcome.SUCCESS;
}
...
}

23. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@EJB
private CustomerFacade customerFacade;
@Inject
private AuthenticationController authController;
...
public Outcome createCustomer() {
CallCenterAgent callCenterAgent = authController.getAuthenticatedUser();
customerFacade.createCustomer(customer, callCenterAgent);
return Outcome.SUCCESS;
}
...
}

24. #WISSENTEILEN
@Stateless
public class CustomerFacade {
@Inject
private CustomerService customerService;
@Inject
private MailService mailService;
private Customer customer;
public void createCustomer(Customer customer,
CallCenterAgentz callCenterAgent) {
customer.updateAuditInformation(callCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
}
…
}
Fühlt sich „fachlich“
nicht wirklich gut an!
Alternativen?

25. #WISSENTEILEN
„Create v5“
TX

26. #WISSENTEILEN
„Delete“

27. #WISSENTEILEN
Der Use Case
UC-002: „delete Customer“
• (JSF) View ruft UI Controller via U-EL
• UI Controller „merkt“ sich Kunde in Session
• UI Controller navigiert zu Bestätigungsseite
• UI Controller bekommt Bestätigung
• …

28. #WISSENTEILEN
„Delete“

29. #WISSENTEILEN
@Named("deleteCustomerController")
@SessionScoped
public class DeleteCustomerController implements Serializable {
@Inject
private CustomerService customerService;
private Customer customer;
public Outcome askForDeletion(Customer aCustomer) {
customer = aCustomer;
return Outcome.SUCCESS;
}
public Outcome deleteCustomer() {
customerService.deleteCustomer(customer);
return Outcome.SUCCESS;
}
}
Wie kommt der Kunde
aus der Session raus?

30. #WISSENTEILEN
Tech
drives
Business

31. #WISSENTEILEN

32. #WISSENTEILEN
TX

33. #WISSENTEILEN
Problemkind Schichtenmodell
• UI Controller via CDI Managed Beans
• Service Facade und Services via EJB/CDI
• Persistenz via EntityManager und Entities
• Alles nur Infrastruktur!
• Wo steckt eigentlich die fachliche Domain?

34. #WISSENTEILEN
TX

35. #WISSENTEILEN
TX

36. #WISSENTEILEN
Refactoring

37. #WISSENTEILEN
Die bessere „neue“
Domänenarchitektur
(Quelle: https://www.bettycrocker.com/recipes/rainbow-surprise-inside-cake/)

38. #WISSENTEILEN
Fachliche Injection

39. #WISSENTEILEN
Fachliche Injection
CDI Producer Methods & Fields
• Factory Method Pattern für fachliche Objekte
• @Produces als Mittel zum Zweck
• @Qualifier als Mittel zur fachlichen Qualifizierung

40. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private AuthenticationController authController;
...
public Outcome createCustomer() {
CallCenterAgent callCenterAgent = authController.getAuthenticatedUser();
customer.updateAuditInformation(callCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}

41. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private AuthenticationController authController;
...
public Outcome createCustomer() {
CallCenterAgent callCenterAgent = authController.getAuthenticatedUser();
customer.updateAuditInformation(callCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}

42. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject ...
private CallCenterAgent callCenterAgent;
...
public Outcome createCustomer() {
customer.updateAuditInformation(callCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}

43. #WISSENTEILEN
@Named("authenticationController")
@SessionScoped
public class AuthenticationController implements Serializable {
@Inject
private UserService UserService;
private CallCenterAgent authenticatedCallCenterAgent;
@Produces ...
public CallCenterAgent getAuthenticatedCallCenterAgent() {
return authenticatedCrmUser;
}
// call center authentication
public String authenticate(...) {
...
}
}
@Inject CallCenterAgent

44. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
public Outcome createCustomer() {
customer.updateAuditInformation(currentCallCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}
Der aktuell angemeldete …

45. #WISSENTEILEN
@Named("authenticationController")
@SessionScoped
public class AuthenticationController implements Serializable {
@Inject
private UserService UserService;
private CallCenterAgent authenticatedCallCenterAgent;
@Produces @Current @RequestScoped
public CallCenterAgent getAuthenticatedCallCenterAgent() {
return authenticatedCrmUser;
}
// call center authentication
public String authenticate(...) {
...
}
}
@Inject @Current CallCenterAgent

46. #WISSENTEILEN
package de.openknowledge.fullstack.jeecrm.annotation;
import …
@Qualifier
@Target({TYPE, METHOD, PARAMETER, FIELD })
@Retention(RUNTIME)
public @interface Current {
// no implementation by default
}

47. #WISSENTEILEN
Fachliche Injection V2

48. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
public Outcome createCustomer() {
customer.updateAuditInformation(currentCallCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}
Cool, oder?

49. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
public Outcome createCustomer() {
customer.updateAuditInformation(currentCallCenterAgent);
customerService.createCustomer(customer);
mailService.sendMail("Welcome", "Welcome to jeeCRM", customer.getEmail());
return Outcome.SUCCESS;
}
...
}
Cool, oder?

50. #WISSENTEILEN
@Stateless
public class CustomerService {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
@PersistenceContext
private EntityManager em;
// transactional by default
public void createCustomer(Customer customer) {
customer.updateAuditInformation(currentCallCenterAgent);
em.persist(customer);
}
...
}
Das ist cool!

51. #WISSENTEILEN
@Stateless
public class CustomerService {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
@PersistenceContext
private EntityManager em;
// transactional by default
public void createCustomer(Customer customer) {
customer.updateAuditInformation(currentCallCenterAgent);
em.persist(customer);
}
...
}
Das ist cool!

52. #WISSENTEILEN
Fachliche Transaktionen

53. #WISSENTEILEN
// Customer Service EJB
@Stateless
public class CustomerService {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
@PersistenceContext
private EntityManager em;
// transactional by default
public void createCustomer(Customer customer) {
customer.updateAuditInformation(currentCallCenterAgent);
em.persist(customer);
}
...
}
Warum EJB?

54. #WISSENTEILEN
// Customer Service CDI ManagedBean
@ApplicationScoped
public class CustomerService {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
@PersistenceContext
private EntityManager em;
// transactional by default
public void createCustomer(Customer customer) {
customer.updateAuditInformation(currentCallCenterAgent);
em.persist(customer);
}
...
} Ok, aber wo bekommen wir
jetzt die Transaktion her?

55. #WISSENTEILEN
// Customer Service CDI ManagedBean
@ApplicationScoped
public class CustomerService {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
...
@PersistenceContext
private EntityManager em;
@javax.transaction.Transactional // JTA 1.2 – TxType.REQUIRED by default
public void createCustomer(Customer customer) {
customer.updateAuditInformation(currentCallCenterAgent);
em.persist(customer);
}
...
}

56. #WISSENTEILEN
TX

57. #WISSENTEILEN
TX

58. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private CustomerService customerService;
...
@Transactional
public Outcome createCustomer() {
customerService.createCustomer(customer);
... // some additional „tx“ related work at use case level
return Outcome.SUCCESS;
}
...
}

59. #WISSENTEILEN
Fachlicher Scope

60. #WISSENTEILEN
Fachlicher Scope
UC-002: „delete Customer“
• Kunde-Löschen-Wizard:
• Kunde zum Löschen aus Tabelle auswählen
• Löschwunsch bestätigen*
• erfolgreiche Löschung anzeigen*
*auf Folgeseite

61. #WISSENTEILEN
Fachlicher Scope
Anti-Pattern „pumped up Session“
• RequestScoped ist zu kurz
• ViewScoped passt irgendwie auch nicht
• SessionScoped aus Mangel an Alternativen

62. #WISSENTEILEN
Fachlicher Scope
Anti-Pattern „pumped up Session“
• RequestScoped ist zu kurz
• ViewScoped passt irgendwie auch nicht
• SessionScoped aus Mangel an Alternativen
• FlowScoped (ab Java EE 7) als Lösung?

63. #WISSENTEILEN
@Named("deleteCustomerController")
@SessionScoped
public class DeleteCustomerController implements Serializable {
@Inject
private CustomerService customerService;
private Customer customer;
public Outcome askForDeletion(Customer aCustomer) {
customer = aCustomer;
return Outcome.SUCCESS;
}
public Outcome deleteCustomer() {
customerService.deleteCustomer(customer);
return Outcome.SUCCESS;
}
}

64. #WISSENTEILEN
Session
Scope

65. #WISSENTEILEN
@RequestScoped
class MyBeanA
@ConversationSoped
class MyWizard
@Inject Conversation conv;
// inside „start“ Methode
conv.begin();
// inside „end“ Methode
conv.end();
@RequestScoped
class MyBeanB
@Inject
@Inject
Conversation
Scope

66. #WISSENTEILEN
@Named("deleteCustomerController")
@ConversationScoped
public class DeleteCustomerController implements Serializable {
@Inject
private Conversation customerDeleteConversation;
...
public Outcome askForDeletion(Customer aCustomer) {
customerDeleteConversation.begin();
customerToDelete = aCustomer;
return Outcome.SUCCESS;
}
@Transactional
public Outcome deleteCustomer() {
... // call backend services
customerDeleteConversation.end();
return Outcome.SUCCESS;
}
}

67. #WISSENTEILEN
@Named("deleteCustomerController")
@ConversationScoped
public class DeleteCustomerController implements Serializable {
@Inject
private Conversation customerDeleteConversation;
...
public Outcome askForDeletion(Customer aCustomer) {
customerDeleteConversation.begin();
customerToDelete = aCustomer;
return Outcome.SUCCESS;
}
@Transactional
public Outcome deleteCustomer() {
... // call backend services
customerDeleteConversation.end();
return Outcome.SUCCESS;
}
}
Was ist, wenn
Conversation schon
aktiv?
Was ist, wenn
Conversation noch
aktiv?

68. #WISSENTEILEN
@Named("deleteCustomerController")
@ConversationScoped
public class DeleteCustomerController implements Serializable {
@Inject
private Conversation customerDeleteConversation;
...
public Outcome askForDeletion(Customer aCustomer) {
if (customerDeleteConversation.isTransient()) {
customerDeleteConversation.begin();
}
customerToDelete = aCustomer;
return Outcome.SUCCESS;
}
...
}

69. #WISSENTEILEN
@Named("deleteCustomerController")
@ConversationScoped
public class DeleteCustomerController implements Serializable {
@Inject
private Conversation customerDeleteConversation;
...
public Outcome cancelDeletion() {
// make sure to end a long-running transaction
if (!conversation.isTransient()) {
conversation.end();
}
return Outcome.SUCCESS;
}
}

70. #WISSENTEILEN
Fachlicher Scope
Conversation eXtended via DeltaSpike
• Normal Conversations
• Grouped Conversations
• Sub Conversations

71. #WISSENTEILEN
Fachliche Methoden

72. #WISSENTEILEN
Fachliche Methoden
a.k.a. „no more doAll(…)-Methods“
• Primärer Use Case: create Customer
• Sekundärer Use Case: send Welcome Mail
• Sekundärer Use Case: trace Trainee Audit Info
• Sekundärer Use Case: if tenant X …

73. #WISSENTEILEN
Fachliche Methoden
Idee der Domänen-Events
• Primärer Use Case löst Event aus
• Sekundäre Use Cases reagieren auf Event

74. #WISSENTEILEN

75. #WISSENTEILEN

76. #WISSENTEILEN
Fachliche Methoden
CDI Events zur losen Kopplung
• Event Object & Event Producer
• Observer Methoden

77. #WISSENTEILEN
Fachliche Methoden
CDI Events zur losen Kopplung
• schichtenneutral für POJOs
• ggf. transaktionsgebunden
• (a)synchrone Interaktion

78. #WISSENTEILEN
Fachliche Methoden
CDI Events? Klingt super, aber ….
• Wie sieht ein solches Event aus?
• Wie fange ich es ab?
• Und vor allem: wie löse ich es aus?

79. #WISSENTEILEN
// event to indicate that a new customer was created
public class CustomerCreatedEvent {
private Customer customer;
public CustomerCreatedEvent(Customer customer) {
this.customer = customer;
}
public Customer getCustomer() {
return this.customer;
}
}

80. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private Event<CustomerCreatedEvent> customerCreatedEventSource;
@Inject
private CustomerService customerService;
private Customer currentCustomer;
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
customerCreatedEventSource.fire(new CustomerCreatedEvent(currentCustomer));
return Outcome.SUCCESS;
} …
}

81. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private Event<CustomerCreatedEvent> customerCreatedEventSource;
@Inject
private CustomerService customerService;
private Customer currentCustomer;
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
customerCreatedEventSource.fire(new CustomerCreatedEvent(currentCustomer));
return Outcome.SUCCESS;
} …
}

82. #WISSENTEILEN
@ApplicationScoped
public class Mailer implements Serializable {
@Inject
private MailService mailService;
public void sendWelcomeMail(@Observes CustomerCreatedEvent event) {
// send welcome mail, if customer has an email address
Customer customer = event.getCustomer();
if (customer.getEmail() != null) {
mailService.sendMail(...);
}
}
public void sendGoodbyeMail(@Observes CustomerDeletedEvent event) {
...
}
}

83. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private Event<CustomerCreatedEvent> eventSource;
@Inject
private CustomerService customerService;
private Customer currentCustomer;
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.fire(new CustomerCreatedEvent(currentCustomer));
return Outcome.SUCCESS;
} …
}
Infrastruktur vs
Fachlichkeit?

84. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Created
private Event<Customer> eventSource;
@Inject
private CustomerService customerService;
private Customer currentCustomer;
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.fire(currentCustomer));
return Outcome.SUCCESS;
} …
}

85. #WISSENTEILEN
@ApplicationScoped
public class Mailer implements Serializable {
@Inject
MailService mailService;
public void sendWelcomeMail(@Observes @Created Customer customer) {
// send welcome mail, if customer has an email address
if (customer.getEmail() != null) {
mailService.sendMail(...);
}
}
public void sendGoodbyeMail(@Observes @Deleted Customer customer) {
...
}
}

86. #WISSENTEILEN
@ApplicationScoped
public class TrackingService implements Serializable {
@Inject @Current
private CallCenterAgent currentCallCenterAgent;
// conditional observer method that takes into account:
// - Transaction status, e.g. AFTER_SUCCESS, AFTER_FAILURE
public void trackCustomerCreated(@Observes(during=AFTER_SUCCESS)
@Created Customer newCustomer) {
// track only if agent is in role TRAINEE
if (Role.TRAINEE.equals(currentCallCenterAgent.getRole()){
this.trackAction(TrackAction.CUSTOMER_CREATED, newCustomer)
}
}
...
}

87. #WISSENTEILEN
@ApplicationScoped
public class GlobalCache implements Serializable {
// conditional observer method that takes into account:
// - Bean instance status: ALLWAYS or IF_EXISTS
// - Transaction status, e.g. AFTER_SUCCESS, AFTER_FAILURE
public void insertIntoCache(@Observes(receive=IF_EXISTS,
during=AFTER=SUCCESS)
@Created Customer newCustomer) { ... }
// conditional observer method that takes into account:
// - Bean instance status: ALLWAYS or IF_EXISTS
// - Transaction status, e.g. AFTER_SUCCESS, AFTER_FAILURE
public void insertIntoCache(@Observes(receive=IF_EXISTS,
during=AFTER=SUCCESS)
@Deleted Customer deletedCustomer) { ... }
...
}

88. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Created
private Event<Customer> eventSource;
...
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.fire(currentCustomer));
return Outcome.SUCCESS;
} …
}
synchronous vs.
asynchronous?

89. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Created
private Event<Customer> eventSource;
...
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.fireAsync(currentCustomer));
return Outcome.SUCCESS;
} …
}
btw: returns a
CompletableStage

90. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Created
private Event<Customer> eventSource;
...
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.fireAsync(currentCustomer)
.whenComplete((event, throwable) -> {
if (throwable != null) { ... } else { ... }
});
return Outcome.SUCCESS;
} …
}
allows beeing
reactive ;-)

91. #WISSENTEILEN
@ApplicationScoped
public class Mailer implements Serializable {
@Inject
private MailService mailService;
public void sendWelcomeMail(@ObservesAsync
@Customer Customer customer) {
...
}
public void sendGoodbyeMail(@ObservesAsync
@Customer Customer customer) {
...
}
}

92. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Created
private Event<Customer> eventSource;
...
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.fire(currentCustomer));
return Outcome.SUCCESS;
} …
}
statische vs. dynamische Qualifier?

93. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject @Created
private Event<Customer> eventSource;
@Inject @TenantId // e.g. @TenantId(“4711“) for tenant „4711“
private String tenantId;
...
// fire event: @Created @Tenant(“4711“) currentCustomer
@Transactional
public Outcome addCustomer() {
// add customer to db via customer service
customerService.createCustomer(currentCustomer);
eventSource.select(new TenantQualifier(tenantId)).fire(currentCustomer));
return Outcome.SUCCESS;
} …
}

94. #WISSENTEILEN
@ApplicationScoped
public class SpecialMailerFor4711 implements Serializable {
@Inject
private MailService mailService;
public void sendWelcomeMail(@Observes @TenantId(“4711“)
@Customer Customer customer) {
...
}
public void sendGoodbyeMail(@Observes @TenantId(“4711“)
@Customer Customer customer) {
...
}
}

95. #WISSENTEILEN
Résumé

96. #WISSENTEILEN
X-Tier Application
a.k.a. Infrastructure-driven Architecture
• technische Injection
• technische Transaktionen
• technische Scopes
• technische Methoden

97. #WISSENTEILEN
TX

98. #WISSENTEILEN
No-Tier Application
a.k.a. Business-driven Architecture
• fachliche Injection
• fachliche Transaktionen
• fachliche Scopes
• fachliche Methoden

99. #WISSENTEILEN
TX

100. #WISSENTEILEN
TX

101. #WISSENTEILEN
Bonus
Material

102. #WISSENTEILEN
TX

103. #WISSENTEILEN
TX

104. #WISSENTEILEN
Fachliche UI Injection

105. #WISSENTEILEN
Fachliche Injection in Views
Views sind nach wie vor ein Problem
• Injection via U-EL
• fachliche von UI Controllern

106. #WISSENTEILEN
<html ...>
<h:body>
<h:form>
Vorname: <h:inputText
value=“#{createCustomerController.customer.firstname}"/>
Name: <h:inputText
value=“#{createCustomerController.customer.lastname}"/>
</h:form>
</h:body>
</html>

107. #WISSENTEILEN
<html ...>
<h:body>
<h:form>
Vorname: <h:inputText
value=“#{customerToCreate.firstname}"/>
Name: <h:inputText
value=“#{customerToCreate.lastname}"/>
</h:form>
</h:body>
</html>

108. #WISSENTEILEN
@Named("createCustomerController")
@RequestScoped
public class CreateCustomerController {
@Inject
private CustomerService customerService;
private Customer customerToCreate;
@Produces
@Named(“customerToCreate“)
public Customer getCustomer () {
return customerToCreate;
}
...
}

109. #WISSENTEILEN
@Named(“customerController")
@RequestScoped
public class CustomerController {
@Inject
private CustomerService customerService;
@Produces
@Named(“customers“)
public Collection<Customer> getAllCustomers() {
return customerService.findAll();
}
@Produces
@Named(“prospects“)
public Collection<Customer> getAllProspects () {
return customerService.findAllOf(CustomerType.PROSPECT);
}
...
}
Infrastructure vs.
Fachlichkeit

110. #WISSENTEILEN
public class CustomerRepository {
@PersistenceContext
private EntityManager em;
@Produces
@Named(“customers“)
public Collection<Customer> findAll() {
return em.createNamedQuery(“customer.findAll“, Customer.class)
.getResultList();
}
@Produces
@Named(“prospects“)
public Collection<Customer> findAllProspects () {
return em.createNamedQuery(“customer.findProspects“, Customer.class)
.getResultList();
}
...
}

111. #WISSENTEILEN
? ? ?

112. #WISSENTEILEN
Kontakt
LARS RÖWEKAMP
CIO NEW TECHNOLOGIES
lars.roewekamp@openknowledge.de
+49 (0)441 4082 – 0
@mobileLarson
@_openknowledge
OFFENKUNDIGGUT

113. #WISSENTEILEN
Bildnachweise
#04 © syda Productions – shutterstock.com
#30 © Dim Tik – shutterstock.com
#36 © Leonova Iuliia – shutterstock.com
#38 © print10 – istockphoto.com
#96 © Liliya Kandrashevich – shutterstock.com
All other pictures inside this presentation orginate
from pixabay.com or were created by my own.