This 15 minutes talk focuses on Dependency Injection with CDI

1. Injection in CDI
in 15 minutes
by antonio goncalves
@agoncal

2. Antonio Goncalves
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3. History of CDI

4. antonio goncalves
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5. History of CDI
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6. @Inject

7. Dependency Injection
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8. Attributes
@Path("/items")
public class ItemRestService {
@Inject
private IsbnGenerator numberGenerator;
@Inject
private ItemEJB itemEJB;
// ...
}
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9. Constructor
@Path("/items")
public class ItemRestService {
private IsbnGenerator numberGenerator;
private ItemEJB itemEJB;
@Inject
public ItemRestService(IsbnGenerator numberGenerator,
ItemEJB itemEJB) {
this.numberGenerator = numberGenerator;
this.itemEJB = itemEJB;
}
// ...
}
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10. Setter
@Path("/items")
public class ItemRestService {
private IsbnGenerator numberGenerator;
private ItemEJB itemEJB;
@Inject
public void setNumberGenerator(IsbnGenerator gen) {
this.numberGenerator = gen;
}
@Inject
public void setItemEJB(ItemEJB itemEJB) {
this.itemEJB = itemEJB;
}
// ...
}
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11. Ambiguous Dependency Injection
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12. Ambiguous Dependency Injection
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13. Qualifiers

14. Type Safe Dependency Injection
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15. Qualifier
@Path("/items")
public class ItemRestService {
@Inject @ThirteenDigits
private NumberGenerator numberGenerator;
@Inject
private ItemEJB itemEJB;
// ...
}
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16. Qualifier and Bean
@Qualifier
@Retention(RUNTIME)
@Target({FIELD, TYPE, METHOD, PARAMETER})
public @interface ThirteenDigits { }
@ThirteenDigits
public class IsbnGenerator implements NumberGenerator {
@Override
public String generateNumber() {
return "13-" + Math.abs(new Random().nextInt());
}
}
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17. Qualifier with Attributes
@Path("/items")
public class ItemRestService {
@Inject @NumberDigits(Digits.Thirteen, true)
private NumberGenerator numberGenerator;
@Inject
private ItemEJB itemEJB;
// ...
}
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18. Multiple Qualifiers
@Path("/items")
public class ItemRestService {
@Inject @ThirteenDigits @Odd
private NumberGenerator numberGenerator;
@Inject
private ItemEJB itemEJB;
// ...
}
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19. Qualifier and Bean
@Qualifier
@Retention(RUNTIME)
@Target({FIELD, TYPE, METHOD, PARAMETER})
public @interface Odd { }
@ThirteenDigits @Odd
public class IsbnGenerator implements NumberGenerator {
@Override
public String generateNumber() {
return "13-" + Math.abs(new Random().nextInt());
}
}
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20. @Default
@Any
@Named

21. Programmatic Lookup
@Path("/items")
public class ItemRestService {
@Inject @ThirteenDigits
private Instance<NumberGenerator> numberGenerator;
@Inject
private ItemEJB itemEJB;
public String getISBN() {
return numberGenerator.get().generateNumber();
}
// ...
}
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22. Programmatic Lookup
@Path("/items")
public class ItemRestService {
@Inject @Any
private Instance<NumberGenerator> numberGenerators;
@Inject
private ItemEJB itemEJB;
public void generateNumbers() {
for(NumberGenerator generator: numberGenerators) {
display(generator.generateNumber());
}
}
// ...
}
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23. Producers

24. Injectable ?
@Path("/items")
public class ItemRestService {
@PersistenceContext(unitName = "myPU")
private EntityManager em;
// ...
}
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25. Injectable ?
@Path("/items")
public class ItemRestService {
@Inject(unitName = "myPU")
private EntityManager em;
// ...
}
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26. Injectable ?
@Path("/items")
public class ItemRestService {
@Inject(unitName = "myPU")
private EntityManager em;
// ...
}
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27. Inject with Qualifier
@Path("/items")
public class ItemRestService {
@Inject @Item
private EntityManager em;
// ...
}
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28. Produce it
@Path("/items")
public class ItemRestService {
@Inject @Item
private EntityManager em;
// ...
}
public class DatabaseProducer {
@Produces
@PersistenceContext(unitName = "myPU")
@Item
private EntityManager em;
}
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29. Strong Typing
Loose coupling

30. </>

31. CDI is Much More !
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32. Thanks
www.antoniogoncalves.org
antonio.goncalves@gmail.com
@agoncal
@devoxxfr
@lescastcodeurs

33. Q&A

34. Creative Commons
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