62 lines
1.8 KiB
Java
62 lines
1.8 KiB
Java
// generics/BankTeller.java
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// (c)2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
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// A very simple bank teller simulation.
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import java.util.*;
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import java.util.function.*;
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class Customer {
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private static long counter = 1;
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private final long id = counter++;
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private Customer() {}
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@Override
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public String toString() { return "Customer " + id; }
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// A method to produce Supplier objects:
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public static Supplier<Customer> generator() {
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return Customer::new; // Constructor reference
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}
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}
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class Teller {
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private static long counter = 1;
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private final long id = counter++;
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private Teller() {}
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@Override
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public String toString() { return "Teller " + id; }
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// A single Supplier object:
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public static Supplier<Teller> generator = Teller::new;
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}
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public class BankTeller {
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public static void serve(Teller t, Customer c) {
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System.out.println(t + " serves " + c);
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}
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public static void main(String[] args) {
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Random rand = new Random(47);
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Queue<Customer> line = new LinkedList<>();
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Suppliers.fill(line, Customer.generator(), 15);
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List<Teller> tellers = new ArrayList<>();
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Suppliers.fill(tellers, Teller.generator, 4);
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for(Customer c : line)
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serve(tellers.get(rand.nextInt(tellers.size())), c);
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}
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}
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/* Output:
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Teller 3 serves Customer 1
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Teller 2 serves Customer 2
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Teller 3 serves Customer 3
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Teller 1 serves Customer 4
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Teller 1 serves Customer 5
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Teller 3 serves Customer 6
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Teller 1 serves Customer 7
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Teller 2 serves Customer 8
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Teller 3 serves Customer 9
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Teller 3 serves Customer 10
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Teller 2 serves Customer 11
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Teller 4 serves Customer 12
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Teller 2 serves Customer 13
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Teller 1 serves Customer 14
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Teller 1 serves Customer 15
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*/
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