Banking-System

This project simulates a banking system. There is support for various types of customers - either personal or commercial as well as support for multiple types of accounts - either checking or savings. Furthermore, a bank branch is represented by a collection of accounts.

What I Learned

How to represent a one to many relationship between classes
Inheritance and using the super keyword in Java
Constructor chaining to invoke all superclasses' constructors
How to call superclass methods from a subclass
How to override superclass methods
Polymorphism, dynamic binding, and generic programming
How to explicitly cast an object from a superclass to a subclass
How to chain toString() methods so a single call displays all of the relevant details/attributes of an entire object

The Problem:

Consider the following problem specification:

A bank system needs to store information about bank Accounts and Customers. The bank supports two different types of accounts (Checking and Savings). All bank accounts have account Number, balance, and date opened. Two Operations are defined for all accounts, makeDeposit() and makeWithdrawal(). Checking accounts have additional attribute for check style and minimum balance. Saving accounts have additional attribute for interest rate and an operation for calculateInterest(). All customers have a name, an address, and a phone number. In addition, a customer can have as many accounts as he needs.

The following is a class diagram for the Bank system described above:

The above specifications have been expanded with new requirements as follows:

There are two special types of customers (Personal and Commercial). Commercial customers have additional attributes for credit rating, contact person, and contact person phone. Personal customers have attributes for home phone and work phone. Moreover, expand the model to show that the bank has multiple branches, and each account is serviced by one branch. Naturally, each branch has many accounts.

The Task:

Create a simple test program (no need for using GUI or Exception Handling, just make it very simple). The name of this test program is Bank.java, it should make use of the above classes. Bank.java should declare an ArrayList to hold all bank accounts. The test program should utilize the system capabilities; The following are sample operations that demonstrate the systems capabilities:
- Create a Checking account for a commercial customer in Kokomo’s branch and add it to the array list
- Create a separate method to display the customer information and account balance. Call the method on behalf of the customer you created in the previous step.
- Deposit a $100 into the account you created in ‘a’, and then display the new info.
- Create a Savings account for an individual customer in some branch with initial balance of $100 and interest rate of 10% and add it to the array list.
- Display the savings account information
- Make a $100 deposit to the savings account, calculate the interest, then display the information
- Implement other operations of your choice!
BONUS: In your second test code, declare an ArrayList of Customers, where each customer will have multiple accounts(one saving and one checking account) in the bank application.
- Insert 8 different customers in the Customers ArrayList.
- Deposit an arbitrary balance for each customer’s checking account.
- Transfer half of the checking balance to saving account of each customer.
- Print out the bank statement of each customer.

UML Diagram

Assumptions

The creditRating within the CommercialCustomer was assumed to be a credit score rather than a credit line. Furthermore, the phoneNumber within the Account class was assumed to represent a PersonalCustomer homePhone or a CommercialCustomer mainline

Notes:

Task 1 has been commented out of the main method. This is so only Task 2 executes when run.
The account numbers within Task 2 for the customers are sequential (1-8 for checking, and 10001-10008 for savings).

zspatter / banking-system