CODEWITHSUNDEEP
javaswingdependency-injection
HastEd
HastEd

Reputation: 35

Double dependencies injection and good practices

Im trying to code an apps in java and i would like to know something about the injections.

I have a class A that inherits from JFrame :

public class A extends JFrame {

public A(CModel model){

    B classB = new B(model);
  }
}

a class B that inherits from JPanel :

public class B extends JPanel {

public CModel model;

public B(CModel model){

    this.model = model;
  }
}

For injecting my Model into my B class, i have to inject it into my A class. Can i do that or is it considered bad practice ? Do i have other choices?

Thanks in advance

Upvotes: 1

Views: 200

Answers (1)

Ian Mc
Ian Mc

Reputation: 5829

In your design, class B requires a CModel (good practice is to make model 'final').

Class A encapsulates B; so while you could first construct B, and inject B into A, there is no good reason to do this. The user who creates A does not need to know about B.

Since B requires a CModel, it follows that A requires a CModel.

The way you have done it best describes A because the only 'state' that is required to construct A is the state required by B.

Upvotes: 1

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