CODEWITHSUNDEEP
javajakarta-eedependency-injectioncdijboss-weld
quartaela
quartaela

Reputation: 2757

Ambiguous dependency while using @Produces annotation

I have been studying @Produces annotation of CDI dependency injection from here. I just created my own same example. However, I am facing with ambiguous dependency.

public interface Bank {

    public void withdrawal();
    public void deposit();
}

public class BankOfAmerica implements Bank {

    @Override
    public void withdrawal() {
        System.out.println("Withdrawal from Bank of America");
    }

    @Override
    public void deposit() {
        System.out.println("Deposit to Bank of America");
    }
}

public class BankFactory {

    @Produces
    public Bank createBank() {
        return new BankOfAmerica();
    }
}

And this is the class which bean is get injected.

public class ProducesExample {

    @Inject
    private Bank bankOfAmerica;

    public void callBanksWithdrawal() {
        bankOfAmerica.withdrawal();
    }
}

I appreciate for any help.

EDIT: I know this a kind of duplicate of this question. However, in the tutorial which I shared, it says it should work. Moreover, there is only one type of bean so no need use @Default or @Alternatives but still get confused about why it is not working.

Upvotes: 0

Views: 1091

Answers (3)

Busterleo
Busterleo

Reputation: 1

You have to add @BankProducer annotation like that :

public class BankFactory {

    @Produces
    @BankProducer
    public Bank createBank() {
        return new BankOfAmerica();
    }

}

Upvotes: 0

Gonçalo
Gonçalo

Reputation: 630

One thing that can be helpful is your beans.xml file.

If you want to have a factory (using @produces) you cannot have the bean-discovery-mode="all". If you have the all option than you will get Ambiguous dependencies exception cause all your implementations will be auto scanned as possible dependencies ( what in my opinion is a bad performance option ).

So put bean-discovery-mode="annotated" , leave your implementations cdi-annotation free and use @Dependent in the factory and @produces in the build method.

Upvotes: 0

Harald Wellmann
Harald Wellmann

Reputation: 12855

The tutorial is a bit ambiguous (pun intended) about which classes should be deployed simulataneously in each step, so I wouldn't worry about that too much.

The answer to the other question you linked does match your case. BankOfAmerica is a bean of type Bank (in CDI 1.0 or in CDI 1.1+ with explicit beans), and your producer method is another bean of the same type, hence the ambiguous resolution.

Upvotes: 1

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