Injecting Objects by Using Producer Methods (original) (raw)
2. Using the Tutorial Examples
3. Getting Started with Web Applications
4. JavaServer Faces Technology
7. Using JavaServer Faces Technology in Web Pages
8. Using Converters, Listeners, and Validators
9. Developing with JavaServer Faces Technology
10. JavaServer Faces Technology: Advanced Concepts
11. Using Ajax with JavaServer Faces Technology
12. Composite Components: Advanced Topics and Example
13. Creating Custom UI Components and Other Custom Objects
14. Configuring JavaServer Faces Applications
16. Uploading Files with Java Servlet Technology
17. Internationalizing and Localizing Web Applications
18. Introduction to Web Services
19. Building Web Services with JAX-WS
20. Building RESTful Web Services with JAX-RS
21. JAX-RS: Advanced Topics and Example
23. Getting Started with Enterprise Beans
24. Running the Enterprise Bean Examples
25. A Message-Driven Bean Example
26. Using the Embedded Enterprise Bean Container
27. Using Asynchronous Method Invocation in Session Beans
Part V Contexts and Dependency Injection for the Java EE Platform
28. Introduction to Contexts and Dependency Injection for the Java EE Platform
Overriding the Scope of a Bean at the Point of Injection
Adding Setter and Getter Methods
Using a Managed Bean in a Facelets Page
Using the @PostConstruct and @PreDestroy Annotations With CDI Managed Bean Classes
To Initialize a Managed Bean Using the @PostConstruct Annotation
To Prepare for the Destruction of a Managed Bean Using the @PreDestroy Annotation
29. Running the Basic Contexts and Dependency Injection Examples
30. Contexts and Dependency Injection for the Java EE Platform: Advanced Topics
31. Running the Advanced Contexts and Dependency Injection Examples
32. Introduction to the Java Persistence API
33. Running the Persistence Examples
34. The Java Persistence Query Language
35. Using the Criteria API to Create Queries
36. Creating and Using String-Based Criteria Queries
37. Controlling Concurrent Access to Entity Data with Locking
38. Using a Second-Level Cache with Java Persistence API Applications
39. Introduction to Security in the Java EE Platform
40. Getting Started Securing Web Applications
41. Getting Started Securing Enterprise Applications
42. Java EE Security: Advanced Topics
Part VIII Java EE Supporting Technologies
43. Introduction to Java EE Supporting Technologies
45. Resources and Resource Adapters
46. The Resource Adapter Example
47. Java Message Service Concepts
48. Java Message Service Examples
49. Bean Validation: Advanced Topics
50. Using Java EE Interceptors
51. Duke's Bookstore Case Study Example
52. Duke's Tutoring Case Study Example
53. Duke's Forest Case Study Example
Producer methods provide a way to inject objects that are not beans, objects whose values may vary at runtime, and objects that require custom initialization. For example, if you want to initialize a numeric value defined by a qualifier named @MaxNumber, you can define the value in a managed bean and then define a producer method, getMaxNumber, for it:
private int maxNumber = 100; ... @Produces @MaxNumber int getMaxNumber() { return maxNumber; }
When you inject the object in another managed bean, the container automatically invokes the producer method, initializing the value to 100:
@Inject @MaxNumber private int maxNumber;
If the value can vary at runtime, the process is slightly different. For example, the following code defines a producer method that generates a random number defined by a qualifier called @Random:
private java.util.Random random = new java.util.Random( System.currentTimeMillis() );
java.util.Random getRandom() { return random; }
@Produces @Random int next() { return getRandom().nextInt(maxNumber); }
When you inject this object in another managed bean, you declare a contextual instance of the object:
@Inject @Random Instance randomInt;
You then call the get method of the Instance:
this.number = randomInt.get();
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