CDI

CDI  @inject  :

Bu su demek :      INFERFACE ‘e uygun classi otomatik bulup, impelements edip,  CONTROLLER OLUSTURUYOR.

NAMED dersen,  senin ismini verdigin   CLASSi  impelements ediyor.

Ref : buraktas.com

Named is CALLED if there are “more than one implementation for an interface.”

 

 

Impelement edilebilir CLASS’larin basina,     @Default.  @Alternative  koyabilirsin. !

From Another  Person :  buraktas.com/create-qualifiers-cdi-beans/

Java CDI Dependency Injection Example

CDI (Context and Dependency Injection) is a specification defined in JSR-299. Major aim is loose coupling by dependency injection.In this tutorial we will see how to use CDI Dependency Injection in java with three different ways;

  • Field injection
  • Constructor injection
  • Setter method injection

We are going to use @Inject alongside @Named annotations from CDI of Java EE. @Named annotation is used for giving names for classes which implements the interface, and it is optional. Otherwise, we can specify alternatives and a default bean by @Alternative, and @Default annotations. However, I am going to show them in this tutorial. Moreover, these are the example interface and implementation classes we are going to use.

Notes:

  • @Named annotation is commonly used if there are more than one implementation for an interface. Thus, it provides to give and inject by their names.
  • If there is only one implementation of an interface and @Named annotation is used, then the name of the bean is determined as camelCase style of class name.
  • We can use @Default and @Alternative annotations instead of giving names to them.
  • If there is only one implementation of an interface, compiler will inject it as the default one. So, there is no need to use @Named, @Default or @Alternative annotations.

Important

We have to create an empty beans.xml file in src/main/resources/META-INF if it is a jar application or src/main/webapp/WEB-INF if it is a war application.
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AutoService.java

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BMWAutoService.java
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FordAutoService.java
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HondaAutoService.java
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AutoServiceCaller.java
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1. Injection Through Fields

Beans are injected through fields.
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2. Injection Through Setter Methods

We can also inject our beans via setters
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3. Injection Through Constructor

Finally, beans can be injected through the constructor of the class.
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