How to increase the number in a class variable in Java every time I make a new object?-CodePudding

I have a class of Orders and it has the number of the order, and it has to increase by 1 every time a new order is created.

I tried to use static but it changed the number of all the orders

Any help?

CodePudding user response：

If it is ID generator you need, there is simple solution with combination of static instance variable

public class Order {
  private static volatile long nextId = 0L;
  private long id;

  public Order (){
    id = nextId  ;
  }
}

EDIT

CodePudding user response：

maybe like that?

public class Order {
  private long id;

  public Order (long lastId){
    id = lastId  ;
  }
}

so, when you create a new you do Order order = new Order(otherOrder);