Reputation:
I have 2 classes Mother and Child
Class Mother :
public class Mother {
private int id;
private String name;
private int age;
public Mother(int id, String name, int age) {
super();
this.id = id;
this.name = name;
this.age = age;
}
Class NewBorn :
public class NewBorn {
private int id;
private String c_daughter;
private String s_son;
private String name;
private int birthdate;
private int weight;
private int height;
private int motherId;
public NewBorn(int id, String c_daughter, String s_son, String name, int birthdate, int weight, int height,int motherId) {
this.id = id;
this.c_daughter = c_daughter;
this.s_son = s_son;
this.name = name;
this.birthdate = birthdate;
this.weight = weight;
this.height = height;
this.motherId = motherId;
}
Of course I have Constructor, setters-getters and to string
I find it not easy to understand this. I do just need to extend one class to another ? like (extend Mother in the NewBorn class?) Can someone please explain how I can implement bidirectional full relation between two objects so further one I can say that (Mother may have many children, children has exactly one mother).
Upvotes: 1
Views: 134
Reputation: 866
To have a full bidirectional relationship, a simplest form should be represented like this:
Class Mother
class Mother {
private Set<Child> children;
// getters, setters, constructors, rest of props
}
Class Child
class Child {
private Mother mother;
// getters, setters, constructors, rest of props
}
You can read more about it here.
Upvotes: 2