JCash.iml

@@ -7,5 +7,15 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library">
+      <library name="JUnit4">
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/junit/junit/4.13.1/junit-4.13.1.jar!/" />
+          <root url="jar://$MAVEN_REPOSITORY$/org/hamcrest/hamcrest-core/1.3/hamcrest-core-1.3.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
   </component>
 </module>

src/Main.java

@@ -1,5 +0,0 @@
-public class Main {
-    public static void main(String[] args) {
-        System.out.println("Hello world!");
-    }
-}

src/me/teridax/jcash/Main.java

@@ -0,0 +1,92 @@
+package me.teridax.jcash;
+
+import me.teridax.jcash.gui.Loader;
+import me.teridax.jcash.gui.account.AccountController;
+import me.teridax.jcash.gui.login.LoginController;
+
+import javax.swing.*;
+
+public final class Main {
+
+    /**
+     * Main instance of this program. Contains the primary window.
+     */
+    private static Main instance;
+
+    /**
+     * Primary window of this program
+     */
+    private final JFrame window;
+
+    private Main() {
+        // create main window and set defaults
+        this.window = new JFrame();
+        this.window.setTitle("Bankautomat");
+        this.window.setLocationByPlatform(true);
+        this.window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+    }
+
+    public static void main(String[] args) {
+        // create main instance and show the login screen
+        instance();
+        getInstance().showLoginScreen();
+    }
+
+    public static Main getInstance() {
+        return instance;
+    }
+
+    /**
+     * Attempts to create a new instance of the singleton class Main.
+     * This method throws an exception if the class is already instantiated.
+     * @throws IllegalStateException if the class is already instantiated
+     * @pre the static instance of this class should be null.
+     * @post the static instance of this class will be set
+     */
+    public static void instance() {
+        if (null != instance)
+            throw new IllegalStateException(Main.class.getName() + " is already initialized");
+
+        Main.instance = new Main();
+    }
+
+    /**
+     * Shows the open dialog for selecting a database file. After selection, it then proceeds to prompt login.
+     * Afterward the selected account can be managed.
+     * This method is non-blocking and all work described is performed asynchronously on the AWT Event dispatcher.
+     */
+    public void showLoginScreen() {
+        SwingUtilities.invokeLater(() -> {
+            try {
+                // select db file
+                var path = Loader.load();
+                // read database and login
+                var login = new LoginController(path);
+
+                // when we have logged in set the account viewer as window content
+                login.addAccountSelectionListener(account -> {
+                    var profileCont = new AccountController(account);
+                    this.window.setContentPane(profileCont.getView());
+                    this.window.revalidate();
+                    this.window.repaint();
+                });
+
+                // we are not logged in yet, so show the login prompt on the main window
+                this.window.setContentPane(login.getView());
+                this.window.setSize(800, 600);
+                this.window.setVisible(true);
+
+            } catch (IllegalStateException e) {
+                System.out.println("no file selected. goodbye");
+            }
+        });
+    }
+
+    /**
+     * Logs the user out of the database, hiding the main window.
+     */
+    public void logout() {
+        window.setContentPane(new JLabel("you're logged out"));
+        window.setVisible(false);
+    }
+}

src/me/teridax/jcash/banking/Account.java

@@ -1,6 +1,6 @@
 package me.teridax.jcash.banking;
 
-import me.teridax.jcash.decode.Decoder;
+import me.teridax.jcash.decode.StringUtils;
 
 import java.util.Objects;
 
@@ -9,7 +9,7 @@ public abstract class Account {
 
     private final int iban;
     private final int pin;
-    private final double balance;
+    private double balance;
 
     public Account(int iban, int pin, double balance) {
         this.iban = iban;
@@ -20,17 +20,17 @@ public abstract class Account {
     public static Account fromColumns(String[] columns) {
         Objects.requireNonNull(columns);
 
-        var iban = Decoder.decodeUniqueIdentificationNumber(columns[0]);
+        var iban = StringUtils.decodeUniqueIdentificationNumber(columns[0]);
-        var pin = Decoder.decodeUniqueIdentificationNumber(columns[1]);
+        var pin = StringUtils.decodeUniqueIdentificationNumber(columns[1]);
-        var balance = Decoder.decodeCurrency(columns[2]);
+        var balance = StringUtils.decodeCurrency(columns[2]);
-        var type = Decoder.decodeName(columns[3]);
+        var type = StringUtils.decodeName(columns[3]);
 
         try {
             if (type.equals("Sparkonto")) {
-                var interest = Decoder.decodePercent(columns[4]);
+                var interest = StringUtils.decodePercent(columns[4]);
                 return new SavingsAccount(iban, pin, balance, interest);
             } else if (type.equals("Girokonto")) {
-                var overdraft = Decoder.decodeCurrency(columns[5]);
+                var overdraft = StringUtils.decodeCurrency(columns[5]);
                 return new Girokonto(iban, pin, balance, overdraft);
             } else {
                 throw new IllegalArgumentException("Invalid account type: " + type);
@@ -64,4 +64,21 @@ public abstract class Account {
 
         return false;
     }
+
+    public String getDescription() {
+        return String.format("%s (%s)", iban, getClass().getSimpleName());
+    }
+
+    public void deposit(double amount) {
+        this.balance += amount;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("@Account [iban=%d, pin=%d, balance=%.2f]", iban, pin, balance);
+    }
+
+    public void takeoff(double amount) {
+        this.balance = Math.max(0, this.balance - amount);
+    }
 }

src/me/teridax/jcash/banking/Bank.java

@@ -1,6 +1,7 @@
 package me.teridax.jcash.banking;
 
 import java.util.*;
+import java.util.regex.Pattern;
 
 @SuppressWarnings("unused")
 public final class Bank {
@@ -46,14 +47,24 @@ public final class Bank {
     }
 
     public static String validateBlz(String maybeBlz) {
-        var builder = new StringBuilder();
+        var pattern = Pattern.compile("[\\w\\d-_]+");
-        maybeBlz.trim().chars().filter(ch -> Character.isDigit(ch) || Character.isLetter(ch)).forEach(builder::append);
+        var matcher = pattern.matcher(maybeBlz);
-        var blz = builder.toString();
 
-        if (blz.isEmpty()) {
+        if (matcher.find())
-            throw new IllegalArgumentException("Bank Blz must only contain letters and digits");
+            return matcher.group();
+
+        throw new IllegalArgumentException("not a valid BLZ: " + maybeBlz);
     }
 
-        return blz;
+    public Optional<Profile> getAccount(int iban) {
+        for (var owner : this.accounts.entrySet()) {
+            for (var account : owner.getValue()) {
+                var tmp = account.getIban();
+                if (tmp == iban) {
+                    return Optional.of(new Profile(owner.getKey(), this, account, getAccountsOfOwner(owner.getKey())));
+                }
+            }
+        }
+        return Optional.empty();
     }
 }

src/me/teridax/jcash/banking/BankingManagementSystem.java

@@ -1,6 +1,6 @@
 package me.teridax.jcash.banking;
 
-import me.teridax.jcash.decode.Decoder;
+import me.teridax.jcash.decode.StringUtils;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -34,7 +34,7 @@ public final class BankingManagementSystem {
                 var account = Account.fromColumns(tail(columns, 2));
 
                 var blz = Bank.validateBlz(columns[1]);
-                var name = Decoder.decodeName(columns[0]);
+                var name = StringUtils.decodeName(columns[0]);
                 var bankOfLine = new Bank(blz, name);
 
                 var bankOfSet = bms.banks.stream().filter(b -> b.equals(bankOfLine)).findFirst();
@@ -54,4 +54,8 @@ public final class BankingManagementSystem {
             throw new IllegalArgumentException("Could not parse file " + file, e);
         }
     }
+
+    public Optional<Bank> getBank(String blz) {
+        return this.banks.stream().filter(b -> b.getBlz().equals(blz)).findFirst();
+    }
 }

src/me/teridax/jcash/banking/Owner.java

@@ -1,6 +1,6 @@
 package me.teridax.jcash.banking;
 
-import me.teridax.jcash.decode.Decoder;
+import me.teridax.jcash.decode.StringUtils;
 
 import java.util.Objects;
 
@@ -28,12 +28,12 @@ public final class Owner {
         if (columns.length != 6)
             throw new IllegalArgumentException("Invalid number of columns: " + columns.length);
 
-        var uid = Decoder.decodeUniqueIdentificationNumber(columns[0]);
+        var uid = StringUtils.decodeUniqueIdentificationNumber(columns[0]);
-        var familyName = Decoder.decodeName(columns[1]);
+        var familyName = StringUtils.decodeName(columns[1]);
-        var name = Decoder.decodeName(columns[2]);
+        var name = StringUtils.decodeName(columns[2]);
-        var street = Decoder.decodeStreet(columns[3]);
+        var street = StringUtils.decodeStreet(columns[3]);
-        var zip = Decoder.decodeUniqueIdentificationNumber(columns[4]);
+        var zip = StringUtils.decodeUniqueIdentificationNumber(columns[4]);
-        var city = Decoder.decodeName(columns[5]);
+        var city = StringUtils.decodeName(columns[5]);
 
         return new Owner(uid, familyName, name, zip, city, street);
     }

src/me/teridax/jcash/banking/Profile.java

@@ -0,0 +1,41 @@
+package me.teridax.jcash.banking;
+
+public class Profile {
+
+    private Owner owner;
+    private Bank bank;
+    private Account primaryAccount;
+    private Account[] accounts;
+
+    public Profile(Owner owner, Bank bank, Account account, Account[] accounts) {
+        this.owner = owner;
+        this.bank = bank;
+        this.accounts = accounts;
+        this.primaryAccount = account;
+    }
+
+    public Account getPrimaryAccount() {
+        return primaryAccount;
+    }
+
+    public Owner getOwner() {
+        return owner;
+    }
+
+    public Bank getBank() {
+        return bank;
+    }
+
+    public Account[] getAccounts() {
+        return accounts;
+    }
+
+    public void setPrimaryAccount(String description) {
+        for (Account account : accounts) {
+            if (account.getDescription().equals(description)) {
+                this.primaryAccount = account;
+                break;
+            }
+        }
+    }
+}

src/me/teridax/jcash/banking/Tests.java

@@ -4,7 +4,7 @@ import org.junit.Test;
 
 import java.nio.file.Paths;
 
-public class Testing {
+public class Tests {
 
     @Test
     public void test() {

src/me/teridax/jcash/decode/StringUtils.java

@@ -10,11 +10,29 @@ import java.util.regex.Pattern;
 
 import static junit.framework.TestCase.assertEquals;
 
-public class Decoder {
+/**
+ * Utility class for converting various single line strings into a specific data type according
+ * to a format mostly dictated by a locale.
+ */
+public class StringUtils {
 
+    /**
+     * Locale to use when converting strings
+     */
     private static final Locale LOCALE = Locale.GERMANY;
-    private static final NumberFormat LOCAL_NUMBER_FORMAT = NumberFormat.getInstance(LOCALE);
+    /**
+     * NumberFormat to use when converting strings
+     */
+    public static final NumberFormat LOCAL_NUMBER_FORMAT = NumberFormat.getInstance(LOCALE);
 
+    /**
+     * Attempts to convert the given string into a double value representing a percentage.
+     * The percentage is stored in the range [0,1] and can linearly be mapped to [0, 100] by multiplying with 100.
+     * @param number the string to convert
+     * @return the double value
+     * @throws IllegalArgumentException when the format is invalid
+     * @throws NullPointerException when the argument is null
+     */
     public static double decodePercent(String number) throws IllegalArgumentException, NullPointerException {
         Objects.requireNonNull(number);
 
@@ -28,6 +46,13 @@ public class Decoder {
         }
     }
 
+    /**
+     * Attempts to convert the given string into a currency value.
+     * @param currency the string to convert
+     * @return the double value
+     * @throws IllegalArgumentException when the format is invalid
+     * @throws NullPointerException when the argument is null
+     */
     public static double decodeCurrency(String currency) throws IllegalArgumentException, NullPointerException {
         Objects.requireNonNull(currency);
 
@@ -38,6 +63,14 @@ public class Decoder {
         }
     }
 
+    /**
+     * Attempts to convert the given string into universally unique number.
+     * This function does not check for duplicates. The number must be a positive integer.
+     * @param number the string to convert
+     * @return the integer serial number
+     * @throws IllegalArgumentException when the format is invalid
+     * @throws NullPointerException when the argument is null
+     */
     public static int decodeUniqueIdentificationNumber(String number) throws IllegalArgumentException, NullPointerException {
         Objects.requireNonNull(number);
 
@@ -56,6 +89,14 @@ public class Decoder {
         }
     }
 
+    /**
+     * Attempts to convert the given string into a name.
+     * This method performs validation and trimming.
+     * @param name the string to convert
+     * @return the qualified name
+     * @throws IllegalArgumentException when the format is invalid
+     * @throws NullPointerException when the argument is null
+     */
     public static String decodeName(String name) throws IllegalArgumentException, NullPointerException {
         Objects.requireNonNull(name);
 
@@ -70,6 +111,13 @@ public class Decoder {
         }
     }
 
+    /**
+     * Attempts to convert the given string into a street and an optional house address.
+     * @param street the string to convert
+     * @return the address name
+     * @throws IllegalArgumentException when the format is invalid
+     * @throws NullPointerException when the argument is null
+     */
     public static String decodeStreet(String street) throws IllegalArgumentException, NullPointerException {
         Objects.requireNonNull(street);
 

src/me/teridax/jcash/gui/Loader.java

@@ -0,0 +1,49 @@
+package me.teridax.jcash.gui;
+
+import me.teridax.jcash.banking.BankingManagementSystem;
+
+import javax.swing.*;
+import javax.swing.filechooser.FileNameExtensionFilter;
+import java.io.File;
+
+import static javax.swing.JFileChooser.APPROVE_OPTION;
+
+/**
+ * Utility class for loading a BMS configuration from a csv file.
+ */
+public class Loader {
+
+    /**
+     * Filter that only allows for files with *.csv extension
+     */
+    private static final FileNameExtensionFilter FILE_FILTER = new FileNameExtensionFilter("Comma separated value spreadsheet", "csv", "CSV");
+
+    private Loader() {}
+
+    /**
+     * Load a BMS from a csv file. Opens up a dialog which prompts the user to select a single file.
+     * Once the file is selected this function will try to parse the contents to a BMS and return the instance.
+     * @return a valid BMS instance loaded from a file
+     * @throws IllegalStateException When either no file is selected or the selected files content is invalid
+     */
+    public static BankingManagementSystem load() throws IllegalStateException {
+        var fileChooser = new JFileChooser();
+        fileChooser.setMultiSelectionEnabled(false);
+        fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
+        fileChooser.setFileFilter(FILE_FILTER);
+        fileChooser.setDialogType(JFileChooser.OPEN_DIALOG);
+        fileChooser.setAcceptAllFileFilterUsed(false);
+        fileChooser.setCurrentDirectory(new File("/home/teridax/IdeaProjects/JCash/res"));
+
+        if (fileChooser.showDialog(null, "Load database") == APPROVE_OPTION) {
+            // parse file content
+            try {
+                return BankingManagementSystem.loadFromCsv(fileChooser.getSelectedFile().toPath());
+            } catch (Exception e) {
+                throw new IllegalStateException("Unable to load database", e);
+            }
+        }
+
+        throw new IllegalStateException("No file selected");
+    }
+}

src/me/teridax/jcash/gui/account/AccountController.java

@@ -0,0 +1,48 @@
+package me.teridax.jcash.gui.account;
+
+import me.teridax.jcash.Main;
+import me.teridax.jcash.banking.Profile;
+import me.teridax.jcash.gui.deposit.DepositDialog;
+import me.teridax.jcash.gui.takeoff.TakeoffDialog;
+import me.teridax.jcash.gui.transfer.TransferDialog;
+
+public class AccountController {
+
+    private final AccountView view;
+
+    public AccountController(Profile profile) {
+        this.view = new AccountView();
+        this.view.setProfile(profile);
+
+        createListeners(profile);
+    }
+
+    private void createListeners(Profile profile) {
+        this.view.getAccountSelection().addActionListener(e -> {
+            var description = ((String) this.view.getAccountSelection().getSelectedItem());
+            profile.setPrimaryAccount(description);
+            this.view.setProfile(profile);
+        });
+
+        this.view.getLogout().addActionListener(e -> {
+            Main.getInstance().logout();
+            Main.getInstance().showLoginScreen();
+        });
+
+        this.view.getDeposit().addActionListener(e -> {
+            new DepositDialog(profile.getPrimaryAccount(), () -> this.view.setProfile(profile));
+        });
+
+        this.view.getTakeoff().addActionListener(e -> {
+            new TakeoffDialog(profile.getPrimaryAccount(), () -> this.view.setProfile(profile));
+        });
+
+        this.view.getTransfer().addActionListener(e -> {
+            new TransferDialog(profile.getPrimaryAccount(), () -> this.view.setProfile(profile));
+        });
+    }
+
+    public AccountView getView() {
+        return view;
+    }
+}

src/me/teridax/jcash/gui/account/AccountView.java

@@ -0,0 +1,170 @@
+package me.teridax.jcash.gui.account;
+
+import me.teridax.jcash.banking.*;
+import me.teridax.jcash.decode.StringUtils;
+
+import javax.swing.*;
+import java.awt.*;
+
+public class AccountView extends JPanel {
+
+    private JTextField iban;
+    private JTextField name;
+    private JTextField address;
+    private JTextField bankName;
+    private JTextField blz;
+    private JTextField type;
+    private JTextField typeSpecialProperty;
+    private JTextField balance;
+
+    private JLabel typeSpecialLabel;
+
+    private JComboBox<String> accountSelection;
+
+    private JPanel content;
+
+    private JButton logout;
+    private JButton transfer;
+    private JButton deposit;
+    private JButton takeoff;
+
+    public AccountView() {
+        createComponents();
+        createLayout();
+
+        setBorder(BorderFactory.createEmptyBorder(8,8,8,8));
+    }
+
+    public void setProfile(Profile profile) {
+        var bank = profile.getBank();
+        var account = profile.getPrimaryAccount();
+        var owner = profile.getOwner();
+
+        this.blz.setText(bank.getBlz());
+        this.bankName.setText(bank.getName());
+
+        this.iban.setText(String.valueOf(account.getIban()));
+        this.name.setText(owner.getName() + " " + owner.getFamilyName());
+        this.address.setText(owner.getStreet() + " " + owner.getCity());
+
+        this.balance.setText(StringUtils.LOCAL_NUMBER_FORMAT.format(account.getBalance()) + " €");
+
+        this.type.setText(account.getClass().getSimpleName());
+        if (account instanceof Girokonto) {
+            this.typeSpecialLabel.setText("Overdraft");
+            this.typeSpecialProperty.setText( StringUtils.LOCAL_NUMBER_FORMAT.format(((Girokonto) account).getOverdraft()) + " €");
+        } else if (account instanceof SavingsAccount) {
+            this.typeSpecialLabel.setText("Interest rate");
+            this.typeSpecialProperty.setText( ((SavingsAccount) account).getInterest() + " %" );
+        }
+
+        this.accountSelection.removeAllItems();
+
+        for (var otherAccount : profile.getAccounts()) {
+            this.accountSelection.addItem(otherAccount.getDescription());
+        }
+        this.accountSelection.setSelectedItem(account.getDescription());
+    }
+
+    private void createLayout() {
+        setLayout(new BorderLayout(16, 16));
+        add(new JScrollPane(content), BorderLayout.CENTER);
+
+        content.setLayout(new GridBagLayout());
+        var constraints = new GridBagConstraints();
+
+        constraints.gridwidth = 4;
+        constraints.insets = new Insets(12,12,12,12);
+
+        var accountSelectionPanel = new JPanel(new BorderLayout(12, 0));
+        accountSelectionPanel.add(iban, BorderLayout.CENTER);
+        accountSelectionPanel.add(accountSelection, BorderLayout.EAST);
+
+        addInputRow(constraints, content, accountSelectionPanel, 1, new JLabel("IBAN", SwingConstants.RIGHT));
+        addInputRow(constraints, content, name, 2, new JLabel("Name/Family-name", SwingConstants.RIGHT));
+        addInputRow(constraints, content, address, 3, new JLabel("Address", SwingConstants.RIGHT));
+        addInputRow(constraints, content, bankName, 4, new JLabel("Bank", SwingConstants.RIGHT));
+        addInputRow(constraints, content, blz, 5, new JLabel("BLZ", SwingConstants.RIGHT));
+        addInputRow(constraints, content, type, 6, new JLabel("Account", SwingConstants.RIGHT));
+        addInputRow(constraints, content, typeSpecialProperty, 7, typeSpecialLabel);
+        addInputRow(constraints, content, balance, 8, new JLabel("Balance", SwingConstants.RIGHT));
+
+        var buttonPanel = Box.createHorizontalBox();
+        buttonPanel.add(Box.createHorizontalStrut(4));
+        buttonPanel.add(logout);
+        buttonPanel.add(Box.createHorizontalStrut(4));
+        buttonPanel.add(Box.createGlue());
+        buttonPanel.add(transfer);
+        buttonPanel.add(Box.createHorizontalStrut(4));
+        buttonPanel.add(deposit);
+        buttonPanel.add(Box.createHorizontalStrut(4));
+        buttonPanel.add(takeoff);
+        add(buttonPanel, BorderLayout.SOUTH);
+    }
+
+    private void createComponents() {
+        this.blz = new JTextField();
+        this.iban = new JTextField();
+        this.address = new JTextField();
+        this.bankName = new JTextField();
+        this.name = new JTextField();
+        this.type = new JTextField();
+        this.balance = new JTextField();
+        this.typeSpecialProperty = new JTextField();
+
+        this.blz.setEditable(false);
+        this.iban.setEditable(false);
+        this.address.setEditable(false);
+        this.bankName.setEditable(false);
+        this.name.setEditable(false);
+        this.type.setEditable(false);
+        this.balance.setEditable(false);
+        this.typeSpecialProperty.setEditable(false);
+
+        this.typeSpecialLabel = new JLabel("", SwingConstants.RIGHT);
+
+        this.accountSelection = new JComboBox<>();
+
+        this.content = new JPanel();
+
+        this.logout = new JButton("Logout");
+        this.transfer = new JButton("Transfer");
+        this.deposit = new JButton("Deposit");
+        this.takeoff = new JButton("Takeoff");
+    }
+
+    private void addInputRow(GridBagConstraints constraints, JComponent target, JComponent comp, int row, JLabel label) {
+        constraints.gridwidth = 1;
+        constraints.gridx = 1;
+        constraints.gridy = row;
+        constraints.weightx = 0;
+        constraints.fill = GridBagConstraints.HORIZONTAL;
+        target.add(label, constraints);
+
+        constraints.gridx = 2;
+        constraints.gridy = row;
+        constraints.weightx = 1;
+        constraints.fill = GridBagConstraints.HORIZONTAL;
+        target.add(comp, constraints);
+    }
+
+    public JComboBox<String> getAccountSelection() {
+        return accountSelection;
+    }
+
+    public JButton getLogout() {
+        return logout;
+    }
+
+    public JButton getTransfer() {
+        return transfer;
+    }
+
+    public JButton getDeposit() {
+        return deposit;
+    }
+
+    public JButton getTakeoff() {
+        return takeoff;
+    }
+}

src/me/teridax/jcash/gui/deposit/DepositDialog.java

@@ -0,0 +1,17 @@
+package me.teridax.jcash.gui.deposit;
+
+import me.teridax.jcash.banking.Account;
+
+public class DepositDialog {
+
+    public DepositDialog(Account account, Runnable onDeposit) {
+        var view = new DepositView(account);
+        view.getDeposit().addActionListener(e -> {
+            account.deposit(view.getAmount());
+            onDeposit.run();
+            view.dispose();
+        });
+        view.getCancel().addActionListener(e -> view.dispose());
+        view.showDialog();
+    }
+}

src/me/teridax/jcash/gui/deposit/DepositView.java

@@ -0,0 +1,115 @@
+package me.teridax.jcash.gui.deposit;
+
+import me.teridax.jcash.banking.Account;
+import me.teridax.jcash.decode.StringUtils;
+
+import javax.swing.*;
+import java.awt.*;
+import java.text.NumberFormat;
+import java.text.ParseException;
+
+public class DepositView {
+
+    private JDialog dialog;
+    private JButton cancel;
+    private JButton deposit;
+    private JFormattedTextField value;
+
+    public DepositView(Account account) {
+        createComponents(account);
+        layoutComponents();
+    }
+
+    public void showDialog() {
+        dialog.setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
+        dialog.setTitle("Deposit money");
+        dialog.pack();
+        dialog.setResizable(false);
+        dialog.setLocationRelativeTo(null);
+        dialog.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
+        dialog.setVisible(true);
+    }
+
+    private void layoutComponents() {
+        dialog.getContentPane().setLayout(new GridBagLayout());
+
+        var c = new GridBagConstraints();
+
+        c.gridx = 0;
+        c.gridy = 0;
+        c.weightx = 1;
+        c.weighty = 1;
+        c.gridwidth = 3;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.CENTER;
+        c.insets = new Insets(4, 4, 4, 4);
+        dialog.getContentPane().add(new JLabel("Deposit money"), c);
+
+        c.gridx = 0;
+        c.gridy = 1;
+        c.gridwidth = 1;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("Value", SwingConstants.RIGHT), c);
+
+        c.gridx = 1;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0.5;
+        dialog.getContentPane().add(value, c);
+
+        c.gridx = 2;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LINE_START;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("€"), c);
+
+        var buttonPanel = new JPanel(new FlowLayout(FlowLayout.TRAILING));
+        buttonPanel.add(cancel);
+        buttonPanel.add(deposit);
+
+        c.gridx = 0;
+        c.gridy = 2;
+        c.gridwidth = 3;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.insets = new Insets(10, 10, 10, 10);
+        dialog.getContentPane().add(buttonPanel, c);
+    }
+
+    private void createComponents(Account account) {
+        this.dialog = new JDialog();
+
+        this.cancel = new JButton("Cancel");
+        this.deposit = new JButton("Deposit");
+        this.value = new JFormattedTextField(StringUtils.LOCAL_NUMBER_FORMAT);
+
+        this.dialog.setContentPane(new JPanel(new GridBagLayout()));
+    }
+
+    public double getAmount() {
+        if (value.getText().isBlank())
+            return 0;
+
+        try {
+            return NumberFormat.getNumberInstance().parse(value.getText()).doubleValue();
+        } catch (ParseException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public JButton getCancel() {
+        return cancel;
+    }
+
+    public JButton getDeposit() {
+        return deposit;
+    }
+
+    public void dispose() {
+        this.dialog.dispose();
+    }
+}

src/me/teridax/jcash/gui/login/AccountSelectionListener.java

@@ -0,0 +1,8 @@
+package me.teridax.jcash.gui.login;
+
+import me.teridax.jcash.banking.Profile;
+
+public interface AccountSelectionListener {
+
+    void onAccountSelected(Profile account);
+}

src/me/teridax/jcash/gui/login/LoginController.java

@@ -0,0 +1,73 @@
+package me.teridax.jcash.gui.login;
+
+import me.teridax.jcash.banking.BankingManagementSystem;
+
+import javax.swing.*;
+import java.awt.event.ActionEvent;
+import java.util.Optional;
+
+public class LoginController {
+
+    private final LoginView view;
+    private final LoginData data;
+
+    private AccountSelectionListener listener;
+
+    public LoginController(BankingManagementSystem bms) {
+        this.view = new LoginView();
+        this.data = new LoginData(bms);
+
+        addActionListeners();
+    }
+
+    private void addActionListeners() {
+        this.view.getLogin().addActionListener(this::login);
+    }
+
+    private Optional<Integer> getIban() {
+        try {
+            var iban = this.view.getIban().getText();
+            return Optional.of(Integer.parseUnsignedInt(iban));
+        } catch (NumberFormatException e) {
+            return Optional.empty();
+        }
+    }
+
+    private Optional<Integer> getPin() {
+        try {
+            var iban = this.view.getPin().getPassword();
+            return Optional.of(Integer.parseUnsignedInt(new String(iban)));
+        } catch (NumberFormatException e) {
+            return Optional.empty();
+        }
+    }
+
+    private void login(ActionEvent ignored) {
+        var blz = this.view.getBlz().getText();
+        var iban = this.getIban();
+        if (iban.isEmpty()) {
+            JOptionPane.showMessageDialog(null, "invalid IBAN", "Faulty login attempt", JOptionPane.ERROR_MESSAGE);
+            return;
+        }
+        var pin = this.getPin();
+        if (pin.isEmpty()) {
+            JOptionPane.showMessageDialog(null, "invalid pin", "Faulty login attempt", JOptionPane.ERROR_MESSAGE);
+            return;
+        }
+
+        var account = this.data.authenticateAccount(blz, iban.get(), pin.get());
+        if (account.isPresent()) {
+            this.listener.onAccountSelected(account.get());
+        } else {
+            JOptionPane.showMessageDialog(null, "invalid login credentials", "Faulty login attempt", JOptionPane.ERROR_MESSAGE);
+        }
+    }
+
+    public void addAccountSelectionListener(AccountSelectionListener listener) {
+        this.listener = listener;
+    }
+
+    public LoginView getView() {
+        return view;
+    }
+}

src/me/teridax/jcash/gui/login/LoginData.java

@@ -0,0 +1,24 @@
+package me.teridax.jcash.gui.login;
+
+import me.teridax.jcash.banking.BankingManagementSystem;
+import me.teridax.jcash.banking.Profile;
+
+import java.util.Optional;
+
+public class LoginData {
+
+    private final BankingManagementSystem bms;
+
+    public LoginData(BankingManagementSystem bms) {
+        this.bms = bms;
+    }
+
+    public Optional<Profile> authenticateAccount(String blz, int iban, int pin) {
+        var optionalBank = bms.getBank(blz);
+        if (optionalBank.isEmpty())
+            return Optional.empty();
+
+        var profile = optionalBank.get().getAccount(iban);
+        return profile.filter(value -> value.getPrimaryAccount().getPin() == pin);
+    }
+}

src/me/teridax/jcash/gui/login/LoginView.java

@@ -0,0 +1,90 @@
+package me.teridax.jcash.gui.login;
+
+import javax.swing.*;
+import javax.swing.text.NumberFormatter;
+import java.awt.*;
+import java.text.NumberFormat;
+
+public class LoginView extends JPanel {
+
+    private final JFormattedTextField blz;
+    private final JFormattedTextField iban;
+    private final JPasswordField pin;
+    private final JButton login;
+
+    public LoginView() {
+        this.blz = new JFormattedTextField("MA2424");
+        this.iban = new JFormattedTextField(getNumberFormat());
+        this.iban.setText("4711");
+        this.pin = new JPasswordField("1234");
+        this.login = new JButton("Login");
+
+        setLayout(new BorderLayout(16, 16));
+        var content = new JPanel();
+        this.setBorder(BorderFactory.createEmptyBorder(8,8,8,8));
+        add(new JScrollPane(content), BorderLayout.CENTER);
+        add(new JLabel("Bankautomat"), BorderLayout.NORTH);
+
+        var layout = new GridBagLayout();
+        var constraints = new GridBagConstraints();
+        content.setLayout(layout);
+
+        constraints.gridwidth = 4;
+        constraints.insets = new Insets(12,12,12,12);
+
+        addInputRow(constraints, content, blz, 1, "BLZ");
+        addInputRow(constraints, content, iban, 2, "Kontonummer");
+        addInputRow(constraints, content, pin, 3, "Passwort");
+
+        constraints.gridy = 4;
+        constraints.anchor = GridBagConstraints.PAGE_END;
+        constraints.weightx = 0;
+        constraints.fill = GridBagConstraints.NONE;
+        constraints.insets = new Insets(12,12,12,12);
+        content.add(login, constraints);
+    }
+
+    private NumberFormatter getNumberFormat() {
+        var format = NumberFormat.getIntegerInstance();
+        format.setGroupingUsed(false);
+
+        var formatter = new NumberFormatter(format);
+        formatter.setValueClass(Integer.class);
+        formatter.setMinimum(0);
+        formatter.setMaximum(Integer.MAX_VALUE);
+        formatter.setAllowsInvalid(false);
+
+        return formatter;
+    }
+
+    private void addInputRow(GridBagConstraints constraints, JComponent target, JComponent comp, int row, String name) {
+        constraints.gridwidth = 1;
+        constraints.gridx = 1;
+        constraints.gridy = row;
+        constraints.weightx = 0;
+        constraints.fill = GridBagConstraints.HORIZONTAL;
+        target.add(new JLabel(name, SwingConstants.RIGHT), constraints);
+
+        constraints.gridx = 2;
+        constraints.gridy = row;
+        constraints.weightx = 1;
+        constraints.fill = GridBagConstraints.HORIZONTAL;
+        target.add(comp, constraints);
+    }
+
+    public JTextField getBlz() {
+        return blz;
+    }
+
+    public JTextField getIban() {
+        return iban;
+    }
+
+    public JPasswordField getPin() {
+        return pin;
+    }
+
+    public JButton getLogin() {
+        return login;
+    }
+}

src/me/teridax/jcash/gui/takeoff/TakeoffDialog.java

@@ -0,0 +1,17 @@
+package me.teridax.jcash.gui.takeoff;
+
+import me.teridax.jcash.banking.Account;
+
+public class TakeoffDialog {
+
+    public TakeoffDialog(Account account, Runnable onTakeoff) {
+        var view = new TakeoffView(account);
+        view.getTakeoff().addActionListener(e -> {
+            account.takeoff(view.getAmount());
+            onTakeoff.run();
+            view.dispose();
+        });
+        view.getCancel().addActionListener(e -> view.dispose());
+        view.showDialog();
+    }
+}

src/me/teridax/jcash/gui/takeoff/TakeoffView.java

@@ -0,0 +1,118 @@
+package me.teridax.jcash.gui.takeoff;
+
+import me.teridax.jcash.banking.Account;
+import me.teridax.jcash.decode.StringUtils;
+
+import javax.swing.*;
+import java.awt.*;
+import java.text.NumberFormat;
+import java.text.ParseException;
+
+import static javax.swing.JOptionPane.ERROR_MESSAGE;
+import static javax.swing.JOptionPane.showMessageDialog;
+
+public class TakeoffView {
+
+    private JDialog dialog;
+    private JButton cancel;
+    private JButton takeoff;
+    private JFormattedTextField value;
+
+    public TakeoffView(Account account) {
+        createComponents(account);
+        layoutComponents();
+    }
+
+    public void showDialog() {
+        dialog.setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
+        dialog.setTitle("Takeoff money");
+        dialog.pack();
+        dialog.setResizable(false);
+        dialog.setLocationRelativeTo(null);
+        dialog.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
+        dialog.setVisible(true);
+    }
+
+    private void layoutComponents() {
+        var c = new GridBagConstraints();
+
+        c.gridx = 0;
+        c.gridy = 0;
+        c.weightx = 1;
+        c.weighty = 1;
+        c.gridwidth = 3;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.CENTER;
+        c.insets = new Insets(4, 4, 4, 4);
+        dialog.getContentPane().add(new JLabel("Takeoff money"), c);
+
+        c.gridx = 0;
+        c.gridy = 1;
+        c.gridwidth = 1;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("Value", SwingConstants.RIGHT), c);
+
+        c.gridx = 1;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0.5;
+        dialog.getContentPane().add(value, c);
+
+        c.gridx = 2;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LINE_START;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("€"), c);
+
+        var buttonPanel = new JPanel(new FlowLayout(FlowLayout.TRAILING));
+        buttonPanel.add(cancel);
+        buttonPanel.add(takeoff);
+
+        c.gridx = 0;
+        c.gridy = 2;
+        c.gridwidth = 3;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.insets = new Insets(10, 10, 10, 10);
+        dialog.getContentPane().add(buttonPanel, c);
+    }
+
+    private void createComponents(Account account) {
+        this.dialog = new JDialog();
+
+        this.cancel = new JButton("Cancel");
+        this.takeoff = new JButton("Takeoff");
+        this.value = new JFormattedTextField(StringUtils.LOCAL_NUMBER_FORMAT);
+
+        this.dialog.setContentPane(new JPanel(new GridBagLayout()));
+    }
+
+    public double getAmount() {
+        if (value.getText().isBlank()) {
+            showMessageDialog(null, "invalid amount", "currency must not be blank", ERROR_MESSAGE);
+            return 0;
+        }
+
+        try {
+            return NumberFormat.getNumberInstance().parse(value.getText()).doubleValue();
+        } catch (ParseException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public JButton getCancel() {
+        return cancel;
+    }
+
+    public JButton getTakeoff() {
+        return takeoff;
+    }
+
+    public void dispose() {
+        this.dialog.dispose();
+    }
+}

src/me/teridax/jcash/gui/transfer/TransferDialog.java

@@ -0,0 +1,17 @@
+package me.teridax.jcash.gui.transfer;
+
+import me.teridax.jcash.banking.Account;
+
+public class TransferDialog {
+
+    public TransferDialog(Account account, Runnable onDeposit) {
+        var view = new TransferView(account);
+        view.getTransfer().addActionListener(e -> {
+            account.takeoff(view.getAmount());
+            onDeposit.run();
+            view.dispose();
+        });
+        view.getCancel().addActionListener(e -> view.dispose());
+        view.showDialog();
+    }
+}

src/me/teridax/jcash/gui/transfer/TransferView.java

@@ -0,0 +1,144 @@
+package me.teridax.jcash.gui.transfer;
+
+import me.teridax.jcash.banking.Account;
+import me.teridax.jcash.decode.StringUtils;
+
+import javax.swing.*;
+import java.awt.*;
+import java.text.NumberFormat;
+import java.text.ParseException;
+
+import static javax.swing.JOptionPane.ERROR_MESSAGE;
+import static javax.swing.JOptionPane.showMessageDialog;
+
+public class TransferView {
+
+    private JDialog dialog;
+    private JButton cancel;
+    private JButton transfer;
+    private JFormattedTextField iban;
+    private JFormattedTextField blz;
+    private JFormattedTextField value;
+
+    public TransferView(Account account) {
+        createComponents(account);
+        layoutComponents();
+    }
+
+    public void showDialog() {
+        dialog.setModalityType(Dialog.ModalityType.APPLICATION_MODAL);
+        dialog.setTitle("Transfer money");
+        dialog.pack();
+        dialog.setSize(dialog.getWidth() * 2, dialog.getHeight());
+        dialog.setResizable(false);
+        dialog.setLocationRelativeTo(null);
+        dialog.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
+        dialog.setVisible(true);
+    }
+
+    private void layoutComponents() {
+        var c = new GridBagConstraints();
+
+        c.gridx = 0;
+        c.gridy = 0;
+        c.weightx = 1;
+        c.weighty = 1;
+        c.gridwidth = 3;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.CENTER;
+        c.insets = new Insets(4, 4, 4, 4);
+        dialog.getContentPane().add(new JLabel("Transfer money"), c);
+
+        c.gridx = 0;
+        c.gridy = 1;
+        c.gridwidth = 1;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("BLZ", SwingConstants.RIGHT), c);
+
+        c.gridx = 1;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0.5;
+        dialog.getContentPane().add(blz, c);
+
+        c.gridx = 2;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("IBAN", SwingConstants.RIGHT), c);
+
+        c.gridx = 3;
+        c.gridy = 1;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 1;
+        dialog.getContentPane().add(iban, c);
+
+        c.gridx = 0;
+        c.gridy = 2;
+        c.fill = GridBagConstraints.NONE;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0;
+        dialog.getContentPane().add(new JLabel("Betrag", SwingConstants.RIGHT), c);
+
+        c.gridx = 1;
+        c.gridy = 2;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.weightx = 0.5;
+        dialog.getContentPane().add(value, c);
+
+        var buttonPanel = new JPanel(new FlowLayout(FlowLayout.TRAILING));
+        buttonPanel.add(cancel);
+        buttonPanel.add(transfer);
+
+        c.gridx = 0;
+        c.gridy = 3;
+        c.gridwidth = 4;
+        c.fill = GridBagConstraints.HORIZONTAL;
+        c.anchor = GridBagConstraints.LAST_LINE_END;
+        c.insets = new Insets(10, 10, 10, 10);
+        dialog.getContentPane().add(buttonPanel, c);
+    }
+
+    private void createComponents(Account account) {
+        this.dialog = new JDialog();
+
+        this.cancel = new JButton("Cancel");
+        this.transfer = new JButton("Transfer");
+        this.value = new JFormattedTextField(StringUtils.LOCAL_NUMBER_FORMAT);
+        this.iban = new JFormattedTextField();
+        this.blz = new JFormattedTextField();
+
+        this.dialog.setContentPane(new JPanel(new GridBagLayout()));
+    }
+
+    public double getAmount() {
+        if (value.getText().isBlank()) {
+            showMessageDialog(null, "invalid amount", "currency must not be blank", ERROR_MESSAGE);
+            return 0;
+        }
+
+        try {
+            return NumberFormat.getNumberInstance().parse(value.getText()).doubleValue();
+        } catch (ParseException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public JButton getCancel() {
+        return cancel;
+    }
+
+    public JButton getTransfer() {
+        return transfer;
+    }
+
+    public void dispose() {
+        this.dialog.dispose();
+    }
+}