Thomas Wiik

classDiagram.puml

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+@startuml
+
+Class Customer {
+- accounts : ArrayList<Account>
++ accountType: enum
++ createAccount(type: AccountType, branch: Branch): void
+}
+
+Class Account {
+- transactionHistory: ArrayList<Transaction>
+- canOverdraft: boolean
+- overdraftRequested: boolean
+- ownerBranch: Branch
+- maxOverdraft: int
+
++ deposit(amount: int): void
++ withdraw(amount: int): boolean
+
++ calculateBalanceFromTransactionHistory(): int
++ generateBankStatement(): void
++ printBankStatement(list: ArrayList<String>): void
+
++ requestOverdraft(): void
++ rejectOverdraftRequest(): void
++ acceptOverdraftRequest(): void
+}
+
+Class Savings extends Account {
+}
+
+Class Current extends Account {
+}
+
+Class Transaction {
+- date: String
+- amount: int
+- currentBalance: int
+}
+
+Class Branch {
+- name: String
+}
+@enduml

domainModel.md

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+# Domain model
+
+## User stories
+### 1
+```
+As a customer,
+So I can safely store and use my money,
+I want to create a current account.
+```
+
+### 2 
+```
+As a customer,
+So I can save for a rainy day,
+I want to create a savings account.
+```
+
+### 3 
+```
+As a customer,
+So I can keep a record of my finances,
+I want to generate bank statements with transaction dates, amounts, and balance at the time of transaction.
+```
+
+### 4 
+```
+As a customer,
+So I can use my account,
+I want to deposit and withdraw funds.
+```
+
+### 5 
+```
+As an engineer,
+So I don't need to keep track of state,
+I want account balances to be calculated based on transaction history instead of stored in memory.
+```
+
+### 6
+```
+As a bank manager,
+So I can expand,
+I want accounts to be associated with specific branches.
+```
+
+### 7
+```
+As a customer,
+So I have an emergency fund,
+I want to be able to request an overdraft on my account.
+```
+
+### 8
+```
+As a bank manager,
+So I can safeguard our funds,
+I want to approve or reject overdraft requests.
+```
+
+### 9
+```
+As a customer,
+So I can stay up to date,
+I want statements to be sent as messages to my phone.
+```
+
+## Classes
+`Construcors, getters and setters have been omitted from the model.`
+
+### Customer Class
+| Variables                     | Description                                                 |
+|-------------------------------|-------------------------------------------------------------|
+| `ArrayList<Account> accounts` | List of all the accounts belonging to a specific customer.  |
+
+| Methods                                                      | Scenario                             | Outputs |
+|--------------------------------------------------------------|--------------------------------------|---------|
+| `void createAccount(AccountType accountType, Branch branch)` | Customer wants to create an account. | -       |
+
+
+### Account Abstract Class
+| Variables                                   | Description                                                                        |
+|---------------------------------------------|------------------------------------------------------------------------------------|
+| `ArrayList<Transaction> transactionHistory` | Contains the history of transactions.                                              |
+| `boolean canOverdraft`                      | Decides if customer can overdraft account.                                         |
+| `boolean overdraftRequested`                | Contains information whether overdrafted has been requested for the given account. |
+| `Branch ownerBranch`                        | Branch associated with account.                                                    |
+| `int maxOverdraft`                          | Max amount the can be overdrafted from the account.                                |
+
+| Methods                                        | Scenario                                                                                       | Outputs                                                                                          |
+|------------------------------------------------|------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------|
+| `void deposit(int amount)`                     | Customer wants to deposit money into the account.                                              | -                                                                                                |
+| `boolean withdraw(int amount)`                 | Customer wants to withdraw money from the account.                                             | If customer has sufficient money in account, or overdraft has been accepted.                     |
+|                                                |                                                                                                | False if customer does not have sufficient money in account and overdraft has not been accepted. |
+| `void generateBankStatement()`                 | Creates list of transactions, including dates, amounts and balance.                            | -                                                                                                |
+| `void printBankStatement()`                    | Prints the bank statement.                                                                     | -                                                                                                |
+| `int calculateBalanceFromTransactionHistory()` | Customer wants account balance to be based on transaction history instead of stored in memory. | -                                                                                                |
+| `void printBankStatement()`                    | Prints either of the aforementioned bank statements.                                           |                                                                                                  |
+| `void requestOverdraft()`                      | Customer wants to be allowed to overdraft the account.                                         | -                                                                                                |
+| `void rejectOverdraftRequest()`                | The manager wants to reject an overdraft request.                                              | -                                                                                                |
+| `void acceptOverdraftRequest()`                | The manager wants to accept an overdraft request.                                              ||
+
+### SavingsAccount extends Account Class
+
+
+### CurrentAccount extends Account Class
+
+### Transaction 
+| Variables            | Description                                      |
+|----------------------|--------------------------------------------------|
+| `String date`        | Contains the date of the transaction.            |
+| `int amount`         | Contains the amount of the transaction.          |
+| `int currentBalance` | Contains the balance at the time of transaction. | 
+
+### Branch Class
+| Variables     | Description                      |
+|---------------|----------------------------------|
+| `String name` | Contains the name of the branch. |
+

src/main/java/com/booleanuk/core/Account.java

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+package com.booleanuk.core;
+
+import java.util.ArrayList;
+
+public abstract class Account {
+    protected ArrayList<Transaction> transactionHistory;
+    protected boolean canOverdraft;
+    protected boolean overdraftRequested;
+    protected Branch ownerBranch;
+    protected int maxOverdraft;
+
+    public Account(Branch branch){
+        this.ownerBranch = branch;
+        this.transactionHistory = new ArrayList<>();
+        this.canOverdraft = false;
+        this.maxOverdraft = -500;
+    }
+
+    public ArrayList<Transaction> getTransactionHistory(){ return this.transactionHistory; }
+    public Branch getOwnerBranch(){ return this.ownerBranch; }
+
+    public void deposit(int amount){
+        if (amount < 1){
+            System.out.println("Invalid amount.");
+            return;
+        }
+
+        int currentBalance = calculateCurrentBalanceFromTransactionHistory();
+        Transaction t = new Transaction(amount, currentBalance);
+        this.transactionHistory.add(t);
+    }
+
+    public boolean withdraw(int amount){
+        if (amount < 1){
+            System.out.println("Invalid amount.");
+            return false;
+        }
+
+        int currentBalance = calculateCurrentBalanceFromTransactionHistory();
+        if (currentBalance < amount){
+            if (!canOverdraft){
+                System.out.println("Insufficient funds.");
+                return false;
+            }
+
+            else if (currentBalance - amount < maxOverdraft){
+                    System.out.println("Exceeding available overdraft.");
+                    return false;
+            }
+        }
+
+        Transaction t = new Transaction(-amount, currentBalance);
+        this.transactionHistory.add(t);
+        System.out.println("Withdrawal successful.");
+        return true;
+    }
+
+    public int calculateCurrentBalanceFromTransactionHistory(){
+        int currentBalance = 0;
+
+        for (Transaction t : this.transactionHistory){
+            currentBalance += t.getAmount();
+        }
+        return currentBalance;
+    }
+
+    public void generateBankStatement(){
+        ArrayList<String> statement = new ArrayList<>();
+        String  s = String.format("%-10s %2s %-10s %2s %-10s %2s %-10s", "date", "||", "credit", "||", "debit", "||", "balance");
+        statement.add(s);
+
+        for (Transaction t : this.transactionHistory){
+            if (0 < t.getAmount()){
+                s = String.format("%-10s %2s %-10s %2s %-10s %2s %-10s", t.getDate(), "||", t.getAmount() + ".00", "||", " ", "||", t.getCurrentBalance() + ".00");
+            } else {
+                s = String.format("%-10s %2s %-10s %2s %-10s %2s %-10s", t.getDate(), "||", " ", "||", -t.getAmount() + ".00", "||", t.getCurrentBalance() + ".00");
+            }
+            statement.add(s);
+        }
+        printBankStatement(statement);
+    }
+
+    private void printBankStatement(ArrayList<String> list){
+        for (String s : list){
+            System.out.println(s);
+        }
+    }
+
+    public void requestOverdraft(){
+        if (!this.overdraftRequested) {
+            this.overdraftRequested = true;
+            System.out.println("Overdraft requested.");
+        } else {
+            System.out.println("Overdraft has already been requested.");
+        }
+    }
+
+    /*
+    The following functionality is meant for the manager only.
+     */
+    public void rejectOverdraftRequest(){
+        if (overdraftRequested) { this.canOverdraft = false; }
+    }
+
+    public void acceptOverdraftRequest(){
+        if (overdraftRequested) { this.canOverdraft = true; }
+    }
+}

src/main/java/com/booleanuk/core/Branch.java

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+package com.booleanuk.core;
+
+public class Branch {
+    private final String name;
+
+    public Branch(String name){
+        this.name = name;
+    }
+
+    public String getName(){
+        return this.name;
+    }
+}

src/main/java/com/booleanuk/core/CurrentAccount.java

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+package com.booleanuk.core;
+
+public class CurrentAccount extends Account{
+    public CurrentAccount(Branch branch){
+        super(branch);
+    }
+}

src/main/java/com/booleanuk/core/Customer.java

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+package com.booleanuk.core;
+
+import java.util.ArrayList;
+
+public class Customer {
+    private final ArrayList<Account> accounts;
+
+    public enum AccountType {
+        SAVINGS,
+        CURRENT
+    }
+
+    public Customer(){
+        this.accounts = new ArrayList<>();
+    }
+
+    public ArrayList<Account> getAccounts(){
+        return this.accounts;
+    }
+
+    public void createAccount(AccountType type, Branch branch){
+        if (type == AccountType.CURRENT) {
+            accounts.add(new CurrentAccount(branch));
+        } else {
+            accounts.add(new SavingsAccount(branch));
+        }
+    }
+}

src/main/java/com/booleanuk/core/Main.java

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+package com.booleanuk.core;
+
+public class Main {
+    public static void main(String[] args){
+        Customer c = new Customer();
+        c.createAccount(Customer.AccountType.CURRENT, new Branch("Oslo"));
+
+        Account account = c.getAccounts().getFirst();
+
+        int deposit = 20;
+
+        int withdraw = 15;
+
+        account.deposit(deposit);
+        account.withdraw(withdraw);
+        account.generateBankStatement();
+    }
+}

src/main/java/com/booleanuk/core/SavingsAccount.java

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+package com.booleanuk.core;
+
+public class SavingsAccount extends Account{
+    public SavingsAccount(Branch branch){
+        super(branch);
+    }
+
+    @Override
+    public void requestOverdraft(){
+        System.out.println("Overdrafting a savings account is not allowed.");
+    }
+
+    /*
+    The following functionality is meant for the manager only.
+     */
+
+    @Override
+    public void rejectOverdraftRequest(){
+        System.out.println("Overdrafting a savings account is not allowed.");
+    }
+
+    @Override
+    public void acceptOverdraftRequest(){
+        System.out.println("Overdrafting a savings account is not allowed.");
+    }
+}