How to do Spring Lookup Method Injection with Annotations?

Question

Is there any way to use Lookup Method Injection using annotations?

Given the following class:

@Service
public abstract class A {


    protected abstract createB();

}

In order to get it to work I have to declare in spring applicationContext.xml the following:

<bean id="b" class="com.xyz.B">
</bean>

<bean id="a" class="com.xyz.A">
    <lookup-method name="createB" bean="b"/>
</bean>

Even though I am using <context:component-scan base> I have to declare it also in the XML. Not a good approach I think.

How to do it with annotations?

score 29 · Accepted Answer · answered May 23 '13 at 13:15

29

It is possible to use javax.inject.Provider. All thanks go to Phil Webb.

public class MySingleton {

  @Autowired
  private Provider<MyPrototype> myPrototype;

  public void operation() {
    MyPrototype instance = myPrototype.get();
    // do something with the instance
  }

}

answered May 23 '13 at 13:15

Andrej Herich

3,246
27
14

1

Please also note the answer about @Lookup below - it's possible with Spring 4.1 ot later to use the annotation. Even though I think the Provider is much cleaner and less confusing while reading the code. – Tarion Sep 25 '15 at 08:35

score 17 · Answer 2 · answered Sep 04 '13 at 00:06

It is also possible with org.springframework.beans.factory.ObjectFactory if you want to keep up with Spring API

public class MySingleton {

  @Autowired
  private ObjectFactory<MyPrototype> myPrototypeFactory;

  public void operation() {
    MyPrototype instance = myPrototypeFactory.getObject();
    // do something with the instance
  }
}

you can read more in the documentation.

Bence Olah · Answer 3 · 2014-12-15T17:56:59.707

13

It is implemented only with Spring >= 4.1 See the ticket.

edited Dec 15 '14 at 17:56

answered Jan 05 '11 at 15:28

Bence Olah

644
6
10

1

In Spring Framework 4.1 it is available as the \@Lookup annotation. See @Danny-Dan's answer. – HairOfTheDog Dec 09 '14 at 19:40
Thanks, udpated my answer accordingly – Bence Olah Dec 15 '14 at 17:57

score 10 · Answer 4 · edited May 23 '17 at 12:00

10

Finally introduced as @Lookup annotation. Here is discussion on how to use it.

edited May 23 '17 at 12:00

Community

1
1

answered Nov 18 '14 at 10:09

Danny Dan

1,215
1
16
32

The @Lookup annotation requires Spring 4.1 or later – HairOfTheDog Dec 09 '14 at 19:35

How to do Spring Lookup Method Injection with Annotations?

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