[Ch15] Ryan and Monica solution in BankAccount

package ch15.ryanmonica;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

public class RyanAndMonicaBankChecksTest {

  public static void main(String[] args) throws InterruptedException {

    BankAccountChecks account = new BankAccountChecks();

    RyanAndMonicaBankChecksJob ryan = new RyanAndMonicaBankChecksJob("Ryan", account);

    RyanAndMonicaBankChecksJob monica = new RyanAndMonicaBankChecksJob("Monica", account);

    ExecutorService executor = Executors.newFixedThreadPool(2);

    executor.execute(ryan);

    executor.execute(monica);

    executor.shutdown();

  }

}

class RyanAndMonicaBankChecksJob implements Runnable {

  private final String name;

  private final BankAccountChecks account;

  RyanAndMonicaBankChecksJob(String name, BankAccountChecks account) {

    this.name = name;

    this.account = account;

  }

  public void run() {

    for (int i = 0; i < 5; i++) {

      goShopping(10);

    }

  }

  private void goShopping(int amount) {

    System.out.println(name + " is about to spend");

    account.spend(name, amount);

    System.out.println(name + " finishes spending");

  }

}

class BankAccountChecks {

  private int balance = 50;

  public int getBalance() {

    return balance;

  }

  public synchronized void spend(String name, int amount) {

    if (getBalance() >= amount) {

      balance = balance - amount;

      if (balance < 0) {

        System.out.println("Overdrawn!");

      }

    } else {

      System.out.println("Sorry, not enough for " + name);

    }

  }

}