Association:
- Association is a relationship between two objects.
- It’s denoted by “has-a” relationship.
- In this relationship all objects have their own lifecycle and there is no owner.
- In Association, both object can create and delete independently.
| One to One: One Customer Has One ID One Menu Item has One ID One to Many: One Customer can have number of Menu orders Many to One: One Menu Item can be ordered by any number of Customers Many to Many: N number of customers can order N menu items |
Program implementation for following Has-A relation :
| class Author { String authorName; int age; String place; Author(String name, int age, String place) { this.authorName = name; this.age = age; this.place = place; } } class Book { String name; int price; Author auther; Book(String n, int p, Author auther) { this.name = n; this.price = p; this.auther = auther; } void bookDetails() { System.out.println(“Book Name: ” + this.name); System.out.println(“Book Price: ” + this.price); } void authorDetails() { System.out.println(“Auther Name: ” + this.auther.authorName); System.out.println(“Auther Age: ” + this.auther.age); System.out.println(“Auther place: ” + this.auther.place); } public static void main(String[] args) { Author auther = new Author(“Srinivas”, 33, “INDIA”); Book obj = new Book(“Java-OOPS”, 200, auther); obj.bookDetails(); obj.authorDetails(); } } |