Best way to create a child object from its parent

Question

Which is the best way to create a child given a parent with data? Would it be ok to have a method with all parents values on the child class as:

public class Child extends Person {
  public Child(Parent p) {
    this.setParentField1(p.getParentField1());
    this.setParentField2(p.getParentField2());
    this.setParentField3(p.getParentField3());
    // other parent fields.
  }
}

to copy parent data ti child object?

Child child = new Child(p);

Why does your `Child` need to be passed a `Parent` to be created? — Daniel Kaplan, Aug 19 '13 at 22:54
@tieTYT maybe, just maybe, the person wants an exact child-clone including all his benefits and bad habits =\ — Luiggi Mendoza, Aug 19 '13 at 23:00

score 18 · Answer 1 · edited Jun 30 '17 at 18:23

18

I would recommend creating a constructor in the parent class that accepts an object of type Parent.

public class Child extends Parent {
  public Child(Parent p) {
     super(p);
  }
}

public class Parent {
   public Parent(Parent p){
      //set fields here
   }
}

edited Jun 30 '17 at 18:23

user1766169

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answered Aug 19 '13 at 22:55

Kevin Bowersox

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12

creating a `Person` object from a `Person` object seems somewhat pointless.. – christopher Aug 20 '13 at 13:04
1

That is the whole point of the question i suppose. – Biscuit Coder Nov 28 '16 at 10:37

score 0 · Answer 2 · edited Jul 09 '17 at 23:21

0

Much simpler is

       public class Child extends Parent {
             public Child(Parent p) {
             //Set fields with parent
           }
       }

Your child object always has access to its parent's fields given the appropriate access modifiers are in place.

edited Jul 09 '17 at 23:21

user1766169

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answered Mar 03 '15 at 03:21

F.O.O

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Best way to create a child object from its parent

2 Answers2