[Ch15] Version of Ryan and Monica that uses a list.

package ch15.ryanmonica;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

import java.util.concurrent.TimeUnit;

public class RyanAndMonicaStatementTest {

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

    BankAccountStatement account = new BankAccountStatement();

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

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

    ExecutorService executor = Executors.newFixedThreadPool(2);

    executor.execute(ryan);

    executor.execute(monica);

    executor.shutdown();

    executor.awaitTermination(1, TimeUnit.MINUTES);

  }

}

class RyanAndMonicaStatementJob implements Runnable {

  private final String name;

  private final BankAccountStatement account;

  RyanAndMonicaStatementJob(String name, BankAccountStatement account) {

    this.name = name;

    this.account = account;

  }

  public void run() {

    for (int i = 0; i < 10; i++) {

      account.makeWithdrawal(10, name);

      if (account.getBalance() < 0) {

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

      }

    }

  }

}

class BankAccountStatement {

  private final List<Withdrawal> statement = new ArrayList<>();

  public BankAccountStatement() {

    statement.add(new Withdrawal("Initial Balance", 0, 100));

  }

  public int getBalance() {

    int lastEntry = statement.size() - 1;

    return statement.get(lastEntry).getCurrentBalance();

  }

  public void makeWithdrawal(int amount, String name) {

    if (getBalance() >= amount) {

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

      try {

        System.out.println(name + " is going to sleep");

        Thread.sleep(500);

      } catch (InterruptedException ex) {ex.printStackTrace();}

      System.out.println(name + " woke up.");

      withdraw(name, amount);

      System.out.println(name + " completes the withdrawal");

    } else {

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

    }

  }

  private void withdraw(String name, int amount) {

    int newBalance = getBalance() - amount;

    Withdrawal withdrawal = new Withdrawal(name, amount, newBalance);

    statement.add(withdrawal);

  }

}

class Withdrawal {

  private final String name;

  private final int amount;

  private final int currentBalance;

  Withdrawal(String name, int amount, int currentBalance) {

    this.name = name;

    this.amount = amount;

    this.currentBalance = currentBalance;

  }

  public String getName() {

    return name;

  }

  public int getAmount() {

    return amount;

  }

  public int getCurrentBalance() {

    return currentBalance;

  }

}