implemented `hashcode`, `equals` for data classes

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

@@ -1,25 +1,20 @@
 package me.teridax.jcash.banking;
 
+import java.util.Objects;
+
 @SuppressWarnings("unused")
 public abstract class Account {
 
-    private int iban;
-    private int pin;
-    private double balance;
+    private final int iban;
+    private final int pin;
+    private final double balance;
 
-    private final Owner owner;
-
-    public Account(int iban, int pin, Owner owner) {
-        this.owner = owner;
+    public Account(int iban, int pin) {
         this.iban = iban;
         this.pin = pin;
         this.balance = 0.0d;
     }
 
-    public Owner getOwner() {
-        return owner;
-    }
-
     public int getIban() {
         return iban;
     }
@@ -31,4 +26,17 @@ public abstract class Account {
     public double getBalance() {
         return balance;
     }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(iban);
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj instanceof Account)
+            return iban == ((Account)obj).iban;
+
+        return false;
+    }
 }

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

@@ -1,26 +1,20 @@
 package me.teridax.jcash.banking;
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Objects;
+import java.util.*;
 
 @SuppressWarnings("unused")
 public final class Bank {
-    private String name;
-    private int blz;
-    private List<Account> accounts;
+    private final String name;
+    private final String blz;
+    private final Map<Owner, Set<Account>> accounts;
 
-    private Bank(int blz, String name) {
+    private Bank(String blz, String name) {
         this.blz = blz;
         this.name = name;
-        this.accounts = new ArrayList<>();
+        this.accounts = new HashMap<>();
     }
 
-    public Account[] getAccounts() {
-        return accounts.toArray(new Account[0]);
-    }
-
-    public int getBlz() {
+    public String getBlz() {
         return blz;
     }
 
@@ -31,20 +25,18 @@ public final class Bank {
     @Override
     public boolean equals(Object obj) {
         if (obj instanceof Bank) {
-            return blz == ((Bank) obj).blz;
+            return Objects.equals(blz, ((Bank) obj).blz);
         }
         return false;
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(blz, name);
+        return Objects.hash(blz);
     }
 
     public Account[] getAccountsOfOwner(Owner owner) {
-        return accounts.stream()
-              .filter(account -> account.getOwner().equals(owner))
-              .toArray(Account[]::new);
+        return accounts.get(owner).toArray(Account[]::new);
     }
 
     private static String validateBlz(String maybeBlz) {

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

@@ -4,14 +4,16 @@ import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 public final class BankingManagementSystem {
 
-    private List<Bank> banks;
+    private final Set<Bank> banks;
 
-    private BankingManagementSystem(List<Bank> banks) {
-        this.banks = banks;
+    private BankingManagementSystem() {
+        this.banks = new HashSet<>();
     }
 
     public static BankingManagementSystem loadFromCsv(File file) {

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

@@ -2,10 +2,10 @@ package me.teridax.jcash.banking;
 
 public class Girokonto extends Account {
 
-    private double overdraft;
+    private final double overdraft;
 
-    public Girokonto(int iban, int pin, double overdraft, Owner owner) {
-        super(iban, pin, owner);
+    public Girokonto(int iban, int pin, double overdraft) {
+        super(iban, pin);
         this.overdraft = overdraft;
     }
 

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

@@ -48,7 +48,7 @@ public final class Owner {
 
     @Override
     public int hashCode() {
-        return Objects.hash(uid, familyName, name, zip, city, street);
+        return Objects.hash(uid);
     }
 
     @Override

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

@@ -3,10 +3,10 @@ package me.teridax.jcash.banking;
 @SuppressWarnings("unused")
 public class SavingsAccount extends Account {
 
-    private double interest;
+    private final double interest;
 
-    public SavingsAccount(int iban, int pin, double interest, Owner owner) {
-        super(iban, pin, owner);
+    public SavingsAccount(int iban, int pin, double interest) {
+        super(iban, pin);
         this.interest = interest;
     }