如何避免编写许多非常相似的setter方法？

Question

I am working on a piece of code where the following applies:

1. I need to instanciate a lot of similar objects within an instance of Class A

2. Each of these objects will then get their own setter in Class B, which corresponds 1:1 to the objects created in the instance of Class A ie In class A:

     B b = new B(); final SomethingA somethingA1 = new SomethingA("input1"); b.setSomethingA(); ... final SomethingB somethingB15 = new SomethingB("input15"); b.setSomethingB15(); ... final SomethingA somethingA23 = new SomethingA("input23"); b.setSomethingA23(); 

Where all "somethings" inherit from the same class.

3. The setter does nothing but:

    public void setSomethingX(somethingX){ this.somethingX = somethingX; } 

I really do not want to write 23 setters that all do almost the same. Is there something like a multi-purpose setter?

The context of this is preparing an HTTP response in a very specific context and using some very specific frameworks. Apparently, this way of doing saves lot of work somewhere else (that I have no influence on). Also, as you can probably tell I am a novice developer.

Answer 1

I'd use Lombok setter/getter for this.

A single annotation that would trigger the creation of those methods. The source code in your IDE will not be polluted with those setters and a lot easier to read.

There is a proposal for data classes, but not yet implemented FYI.

Answer 2

There are couple technics to reduce setters:

1) Create constructor with B as parameter

class A {

    private B b;

    public A(B b) {
        this.b = b;
    }    
}  

A a = new A(new B());

2) Use builder pattern (with lombok will be easy to implement):

@Builder // lombok annotation
class A {
    private B b;
}

A a = A.builder().withB(b).build();

3) Use factory method:

class A {

    private B b;

    public static A newInstance(B b) {
        A a = new A();
        a.b = b;
        return a;
    }

}

A a = A.newInstance(new B());