How to use PicoContainer for a constructor with paramenter

Question

I am using PicoContainer and I have to add a component which has a constructor with paramenter. So I have

public abstract class IA {

   @Inject
   protected B b;

   public void useB(){
        b.useSomeMethodOfB();
   }
}

public interface IC{}

public class C implements IC{}

public class A extends IA{

     private IC mSomeOtherComponent;

     public A(IC someOtherComponent){
         mSomeOtherComponent = someOtherComponent
     }
}

Now to instatiate this component I have:

MutablePicoContainer context = new PicoBuilder().withAnnotatedFieldInjection().withCaching().build();

then

contex.addComponent(A.class, new A(new C()));

but when I call useB() method in the abstract class it returns null, it doesn't inject anything. I think it's not right the way I added the component. I also tried;

ComponentParameter pr = new ComponentParameter(new C());
context.addComponent(IA.class, A.class, pr);

and

 ComponentParameter pr = new ComponentParameter(new C());
 context.addComponent(A.class, A.class, pr);

but it says that "A has unsatisfied dependency for fields B.

How could I solve it?

`contex.addComponent(B.class, new A(new C()));`? (I have heard of PicoContainer, but still not used it.) — Joop Eggen, Nov 28 '14 at 10:04
I am new with it, as I told I don't think it's the right way to do it. — Shilaghae, Nov 28 '14 at 10:15

score 0 · Answer 1 · answered Nov 28 '14 at 10:21

It's not so intuitive

public interface ThreadPool {  
 void setSize(int);  
}  

public class MyComp {  
 private ThreadPool threadPool;
 public MyComp(ThreadPool pool) {  
    threadPool = pool;  
    threadPool.setSize(size);  
 }  
}

In order to invoke the MyComp(ThreadPool pool) constructor you've to do the following :

DefaultPicoContainer pico = new DefaultPicoContainer();  
pico.addComponent(ThreadPool.class, DefaultThreadPool.class);  
pico.addComponent(MyComp.class, MyComp.class);

MyComp myComp = (MyComp)pico.getInstance(MyComp.class);

As you notice, the fact that you registred ThreadPool before instantiating MyComp, that will satisfy "greediest" condition to let PicoContainer invoke the parametrized constructor instead of the default one.

more information here

Cheers

I hope I understood what you mean, you can see how I did it in one of the answers before, please check if it is what you meant. — Shilaghae, Dec 01 '14 at 09:46

score 0 · Answer 2 · answered Nov 29 '14 at 15:27

0

Do you have B in the container? If you can't inject it in the constructor you can use http://picocontainer.codehaus.org/multi-injection.html to inject both field and constructor

answered Nov 29 '14 at 15:27

xeye

1,250
10
15

Shilaghae · Answer 3 · 2014-12-01T09:49:22.447

0

I ended up injecting the constructor

    context.addComponent(IC.class, C.class);

    context.addComponent(A.class, A.class);

and in class A I injected the constructor so:

    @Inject
    private IC c;

So now depending on what I need I can add to the context whatever implementation of C class I need.

edited Dec 01 '14 at 09:49

answered Dec 01 '14 at 09:43

Shilaghae

957
12
22

Hi but doing like that didn't work either, because it kept saying that B has not initialized... :/ – Shilaghae Dec 01 '14 at 11:32

How to use PicoContainer for a constructor with paramenter

3 Answers3