Lab for Objects and Classes

Go to this URL to accept the lab and create your repository: https://classroom.github.com/a/ubpc4JQ8

Clone the repository to your workspace. The command is similar to this:

cmd> git clone https://github.com/OOP2018/objectslab-yourname.git objectslab

Do the problems. Test and review your code. “Review” means carefully read it from start to end.

Commit to your local repository and push to Github:

cmd> git status
cmd> git add src/banking/BankTest.java
cmd> git add src/banking/BankAccountTest.java
cmd> etc.
cmd> git commit -m "Finished the lab"
cmd> git push

Problems

There are 4 problems. The classes and packages are:

Problem	Package	Files to complete
1. Person	`person`	`Person.java` `Main.java`
	(none)	`README.md` - answer the question
2. BankAccount	`banking`	`BankAccount.java` and `BankAccountTest.java`
3. Bank	`banking`	`Bank.java` and `BankTest.java`
4. BankApp	`banking`	`BankApp.java`

Problem 1. Write a Person class and create Person objects

1.1 Write a Person class in the person package, with these attributes and methods:

String name	person's name, private
String email	person's email, private
Person(String name)	constructor that initializes a person's name. email is empty string (not null)
String getName() void setName(String newname)	Getter and Setter for Person's name
String getEmail() void setEmail(String email)	Getter and Setter for Person's email
String toString()	Return string description such as: "Bill Gates <bill@msft.com>".

package person;
/**
 * Write a description of Person.
 * @author your name
 */
public class Person {
    //TODO declare the attributes

    /** initialize a new person with a name */
    public Person(String name) {
        //TODO write the constructor
    }

1.2 Write a Main class in the person package to test the Person class. In the main method, ask for the name and email of 2-3 friends. Save them in an ArrayList (ok to use array if stuck on ArrayList), and then print each person using System.out.println. Note the println(person) will invoke person.toString().

Example of running Main:

Input friend name (blank line to end): Bill Gates
Email: bill@msft.com
Input friend name (blank line to end): Donald Trump
Email: [ENTER]
Input friend name (blank line to end): Harry Hacker
Email: hacker@blackhat.org
Input friend name (blank line to end): [ENTER]  <-- blank input to exit loop

Your friends are:
Bill Gates <bill@msft.com>
Donald Trump
Harry Hacker <hacker@blackhat.org>

Hint: Use scanner.nextLine() to read entire line and string.trim() to remove leading/trailing spaces.

1.3 Modify Person to make the name attribute be static, like this:

public class Person {
    private static String name;

Run Main again. Explain why the output is different. Write your answer is README.md and submit README.md with your code.

Eclipse and Netbeans give a warning about accessing static attributes through instance references – its legal but usually not what you want.

1.4 Fix the code. Make name be an instance attribute again.

Problem 2. BankAccount and BankAccountTest

Use the package banking for Problems 2-4.

2.1 Create a BankAccount class in banking package with these attributes, constructor, and methods. The attributes should be private.

Member	Description
Long accountNumber	the bank account number
String accountName	the account name. Usually a person's name.
double balance	account balance, initially 0.0.
BankAccount(String name)	constructor with a bank account name. The balance is 0. Get an accountNumber from the Bank (use starter code) like this: `accountNumber = Bank.getNextAccountNumber();`
BankAccount(String name, long accountNum)	constructor for BankAccount with a specified account name and account number (don’t get accountNumber from Bank).
String getName() void setName(String newname)	Getter and Setter for the account name
double getAccountNumber()	Get the account number. No setAccountNumber method. (You can't change a bank account number.)
double getBalance()	Return the balance. No setBalance method.
void deposit(double amount)	Deposit money to account. amount must be positive.
boolean withdraw(double amount)	Withdraw money from account. amount must be postive and not exceed the balance. Return true if withdraw succeeds, false if not allowed (amount not valid).
String toString()	Return description of account in the format: "[1234567890] Bill Gates, balance: 2,000,000,000.00 Bt"

2.2 BankAccountTest class: Design and code this class yourself.

You should test all the BankAccount methods and show results. It can be interactive (prompt for input) or just run fixed code. Example:

Enter Account name:  Taksin
Enter Account number: 1234567890
  Created new account. 
  toString(): [1234567890] Taksin, balance: 0.00 Bt
  getBalance(): 0.00
Deposit (+) or withdraw (-): +1000000000
  Deposit 1,000,000,000.00 Bt
  toString(): [1234567890] Taksin, balance: 1,000,000,000.00 Bt
  getBalance(): 1,000,000,000.00
Deposit (+) or withdraw (-): +5.99
  Deposit 5.99 Bt
  toString(): [1234567890] Taksin, balance: 1,000,000,005.99 Bt
  getBalance(): 1,000,000,005.99
Deposit (+) or withdraw (-): -999000000
  withdraw 999,999,999.00 Bt succeeded
  toString(): [1234567890] Taksin, balance: 1,000,005.99 Bt
  getBalance(): 1,000,005.99
Deposit (+) or withdraw (-): -2000000
  withdraw 2,000,000.00 Bt failed
  toString(): [1234567890] Taksin, balance: 1,000,005.99 Bt
  getBalance(): 1,000,005.99
Deposit (+) or withdraw (-): -1000005.99    (try to withdraw everything)
  withdraw 1,000.005.99 Bt succeeded
  toString(): [1234567890] Taksin, balance: 0.00 Bt
  getBalance(): 0.00

Problem 3. Bank and BankTest

The Bank is responsible for knowing about all bank accounts, adding accounts, finding accounts, and assigning account numbers. Starter code is provided.

There should only be one Bank. So, let the Bank behavior be static.

Member	Description
static long nextAccountNumber	the next available account number.
static List<BankAccount> accounts	all the bank accounts
private Bank()	private constructor to guarantee that no other code creates Bank objects. (Try it! In another class try to write `new Bank()`.)
static long getNextAccountNumber()	return the next available account number, and then increment it by 1.
static void addAccount(BankAccount acct)	Add a new bank account to List of accounts. If another account with same account number is already in List, then don't add it! (Account numbers should be unique.)
static BankAccount getAccount(long accountNumber)	Find a BankAccount with the requested account number and return it. If no account with requested accountNumber, return null.
static List<BankAccount> getAccounts()	Return List of all the bank accounts.

Note: We could design the Bank without using static. Its called the Singleton Pattern (allows you to create only 1 object of a class). You’ll learn that later.

3.2 BankTest: Write a BankTest class with a main method to test the Bank. Starter code is provided, but you must write more tests. Test every Bank method:

Bank.getNextAccountNumber() always increases by 1
Bank.addAccount( bankAccount ) really adds accounts
Bank.addAccount( bankAccount ) won’t let you add same account twice, or 2 accounts with same account number.
Bank.getAccount(number) returns the correct account, or null if no such account number.
Bank.getAccounts() returns all the BankAccounts

Problem 4. BankApp

An “application class” that simulates a banking operation. It interacts with the user and uses BankAccount and Bank. Starter code is provided, but you need to complete several methods.

Please see the TODO comments in code.

This class won’t compile until you complete BankAccount and Bank.

Sample run:

Input one of the following:
n              - (new) create a new bank account
d              - deposit to an account
w              - withdraw from an account
l              - list all accounts with balances
p acctNumber   - print info for one account (e.g. p 123456)
q              - quit
?              - print this menu again

Input: n
Create a new account
Enter account name: Bill Gates
Created new account no. 100, name "Bill Gates".
Input: d
Please enter account number: 100
Account [100] Bill Gates
Amount to deposit: 500000
Deposited 500,000 Bt. Balance is 500,000 Bt.
Input: w
Please enter account number: 100
Account [100] Bill Gates
Amount to withdraw: 200000
Withdrew 200,000 Bt. Balance is 300,000 Bt.
Input: n
Create a new account
Enter account name: George Bush
Created new account no. 101, name "George Bush".
Input: d
Please enter account number: 101
Account [101] George Bush
Amount to deposit: 1000000
Deposited 1,000,000 Bt. Balance is 1,000,000 Bt.
Input: l
Acct No.   Name           Balance
  100      Bill Gates      300,000.00
  101      George Bush   1,000,000.00
Input: 