OnJava8-Examples/generics/BankTeller.java

// generics/BankTeller.java
// (c)2016 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
// A very simple bank teller simulation
import java.util.*;
import onjava.*;

class Customer {
  private static long counter = 1;
  private final long id = counter++;
  @Override
  public String toString() { return "Customer " + id; }
}

class Teller {
  private static long counter = 1;
  private final long id = counter++;
  @Override
  public String toString() { return "Teller " + id; }
}

class Bank {
  private List<BankTeller> tellers = new ArrayList<>();
  public void put(BankTeller bt) { tellers.add(bt); }
}

public class BankTeller {
  public static void serve(Teller t, Customer c) {
    System.out.println(t + " serves " + c);
  }
  public static void main(String[] args) {
    // Demonstrate create():
    RandomList<Teller> tellers =
      Suppliers.create(RandomList::new, Teller::new, 4);
    // Demonstrate fill():
    List<Customer> customers = Suppliers.fill(
      new ArrayList<>(), Customer::new, 12);
    customers.forEach(c -> serve(tellers.select(), c));
    // Demonstrate assisted latent typing:
    Bank bank = Suppliers.fill(
      new Bank(), Bank::put, BankTeller::new, 3);
    // Can also use second version of fill():
    List<Customer> customers2 = Suppliers.fill(
      new ArrayList<>(), List::add, Customer::new, 12);
  }
}
/* Output:
Teller 3 serves Customer 1
Teller 2 serves Customer 2
Teller 3 serves Customer 3
Teller 1 serves Customer 4
Teller 1 serves Customer 5
Teller 3 serves Customer 6
Teller 1 serves Customer 7
Teller 2 serves Customer 8
Teller 3 serves Customer 9
Teller 3 serves Customer 10
Teller 2 serves Customer 11
Teller 4 serves Customer 12
*/