From bdcab34d66a187f7dee7bf0b885e99a8b2510e32 Mon Sep 17 00:00:00 2001
From: "github-classroom[bot]"
 <66690702+github-classroom[bot]@users.noreply.github.com>
Date: Mon, 6 Oct 2025 08:58:32 +0000
Subject: [PATCH 01/17] GitHub Classroom Feedback

---
 .github/.keep | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 .github/.keep

diff --git a/.github/.keep b/.github/.keep
new file mode 100644
index 00000000..e69de29b

From baa14eb1ffd66d8930f39a3663074b96ca5af50a Mon Sep 17 00:00:00 2001
From: "github-classroom[bot]"
 <66690702+github-classroom[bot]@users.noreply.github.com>
Date: Mon, 6 Oct 2025 08:58:32 +0000
Subject: [PATCH 02/17] Setting up GitHub Classroom Feedback


From fc4ad1d0278e800b053b2188dd11fca0a7342a42 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Mon, 20 Oct 2025 08:44:58 +0200
Subject: [PATCH 03/17] Initial Commit

---
 src/main/java/com/example/Category.java       | 31 +++++++
 .../java/com/example/ElectronicsProduct.java  | 24 +++++
 src/main/java/com/example/FoodProduct.java    | 48 ++++++++++
 src/main/java/com/example/Perishable.java     | 26 ++++++
 src/main/java/com/example/Perishables.java    | 13 +++
 src/main/java/com/example/Product.java        | 37 ++++++++
 src/main/java/com/example/Shippable.java      |  8 ++
 src/main/java/com/example/Warehouse.java      | 90 +++++++++++++++++++
 .../java/com/example/WarehouseAnalyzer.java   |  3 +
 9 files changed, 280 insertions(+)
 create mode 100644 src/main/java/com/example/Category.java
 create mode 100644 src/main/java/com/example/ElectronicsProduct.java
 create mode 100644 src/main/java/com/example/FoodProduct.java
 create mode 100644 src/main/java/com/example/Perishable.java
 create mode 100644 src/main/java/com/example/Perishables.java
 create mode 100644 src/main/java/com/example/Product.java
 create mode 100644 src/main/java/com/example/Shippable.java
 create mode 100644 src/main/java/com/example/Warehouse.java

diff --git a/src/main/java/com/example/Category.java b/src/main/java/com/example/Category.java
new file mode 100644
index 00000000..d20d772c
--- /dev/null
+++ b/src/main/java/com/example/Category.java
@@ -0,0 +1,31 @@
+package com.example;
+
+public class Category {
+    static String name;
+
+    private Category(String categoryName) {
+
+    }
+
+    public static Category of(String name) {
+        if (name == null || name.isEmpty()) {
+            throw new IllegalArgumentException("Category name cannot be null or empty");
+        }
+        name = name;
+
+        name = name.substring(0, 1).toUpperCase()
+                + name.substring(1).toLowerCase();
+
+        return new Category(name);
+
+    }
+
+    public String getName() {
+        return name;
+    }
+
+}
+
+/*
+Cache/flyweight: return the same instance for the same normalized name.
+ */
diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
new file mode 100644
index 00000000..9b0fb3b8
--- /dev/null
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -0,0 +1,24 @@
+package com.example;
+
+import java.math.BigDecimal;
+import java.util.UUID;
+
+public class ElectronicsProduct extends Product {
+    public ElectronicsProduct(UUID id, String name, Category category, BigDecimal price, int warranty, BigDecimal weight) {
+    }
+
+    @Override
+    public String productDetails() {
+        return "";
+    }
+
+    @Override
+    public BigDecimal getPrice() {
+        return null;
+    }
+
+    @Override
+    public UUID uuid() {
+        return null;
+    }
+}
diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
new file mode 100644
index 00000000..e6ed6b1a
--- /dev/null
+++ b/src/main/java/com/example/FoodProduct.java
@@ -0,0 +1,48 @@
+package com.example;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.util.UUID;
+
+public class FoodProduct extends Product implements Perishables, Shippable {
+    public LocalDate expirationDate;
+    public BigDecimal weight;
+
+    public FoodProduct(UUID id, String name, Category category, BigDecimal price, LocalDate expirationDate, BigDecimal weight) {
+
+    }
+
+
+    @Override
+    public BigDecimal getPrice() {
+        return null;
+    }
+
+    @Override
+    public UUID uuid() {
+        return null;
+    }
+
+    @Override
+    public String productDetails() {
+        return "";
+    }
+
+    @Override
+    public double weight() {
+        return 0;
+    }
+
+    @Override
+    public BigDecimal calculateShippingCost() {
+        return null;
+    }
+}
+
+/*
+Implements Perishable and Shippable.
+Fields: LocalDate expirationDate, BigDecimal weight (kg).
+Validations: negative price -> IllegalArgumentException("Price cannot be negative."); negative weight -> IllegalArgumentException("Weight cannot be negative.").
+productDetails() should look like: "Food: Milk, Expires: 2025-12-24".
+Shipping rule: cost = weight * 50.
+ */
\ No newline at end of file
diff --git a/src/main/java/com/example/Perishable.java b/src/main/java/com/example/Perishable.java
new file mode 100644
index 00000000..e31cc191
--- /dev/null
+++ b/src/main/java/com/example/Perishable.java
@@ -0,0 +1,26 @@
+package com.example;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.util.UUID;
+
+public class Perishable extends Product{
+    public LocalDate expirationDate() {
+        return LocalDate.now();
+    }
+
+    @Override
+    public String productDetails() {
+        return "";
+    }
+
+    @Override
+    public BigDecimal getPrice() {
+        return null;
+    }
+
+    @Override
+    public UUID uuid() {
+        return null;
+    }
+}
diff --git a/src/main/java/com/example/Perishables.java b/src/main/java/com/example/Perishables.java
new file mode 100644
index 00000000..6e5151c1
--- /dev/null
+++ b/src/main/java/com/example/Perishables.java
@@ -0,0 +1,13 @@
+package com.example;
+
+import java.math.BigDecimal;
+import java.time.LocalDate;
+import java.util.UUID;
+
+public interface Perishables {
+    LocalDate expirationDate = null;
+    public BigDecimal getPrice();
+
+
+    UUID uuid();
+}
diff --git a/src/main/java/com/example/Product.java b/src/main/java/com/example/Product.java
new file mode 100644
index 00000000..50adde73
--- /dev/null
+++ b/src/main/java/com/example/Product.java
@@ -0,0 +1,37 @@
+package com.example;
+
+import java.math.BigDecimal;
+import java.util.UUID;
+
+
+
+public abstract class Product implements Perishables {
+    UUID uuid;
+    String name;
+    Category category;
+    BigDecimal price;
+
+
+    public BigDecimal price() {
+        return price;
+    }
+
+    public void setPrice(BigDecimal price) {
+        this.price = price;
+    }
+
+    public UUID uuid() {
+        return uuid;
+    }
+
+    public String name() {
+        return name;
+    }
+
+    public Category category() {
+        return category;
+    }
+
+    public abstract String productDetails();
+
+}
diff --git a/src/main/java/com/example/Shippable.java b/src/main/java/com/example/Shippable.java
new file mode 100644
index 00000000..eb9fd2c4
--- /dev/null
+++ b/src/main/java/com/example/Shippable.java
@@ -0,0 +1,8 @@
+package com.example;
+
+import java.math.BigDecimal;
+
+public interface Shippable {
+    double weight();
+    BigDecimal calculateShippingCost();
+}
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
new file mode 100644
index 00000000..9a69d95f
--- /dev/null
+++ b/src/main/java/com/example/Warehouse.java
@@ -0,0 +1,90 @@
+package com.example;
+
+import java.math.BigDecimal;
+import java.util.*;
+
+public class Warehouse {
+    List<Product> products;
+    List<Shippable> shippables;
+
+    private static Warehouse single_instance = null;
+    public String instanceName;
+
+    public List<Product> getProducts(){
+        return products;
+    }
+
+    public List<Shippable> shippableProducts() {
+        return shippables;
+    }
+
+    public void clearProducts(){
+        products.clear();
+    }
+
+    public boolean isEmpty(){
+        return products.isEmpty();
+    }
+
+    public void addProduct(Product product){
+        products.add(product);
+    }
+
+    public void remove(UUID id){
+        for(Product product : products){
+            if (product.uuid == id)
+                products.remove(product);
+        }
+    }
+
+    public Optional<Product> getProductById(UUID id){
+       var temp = products.stream()
+               .filter(product -> product.uuid == id)
+               .findFirst()
+               .isEmpty();
+
+       if(temp){
+           return Optional.empty();
+       } else {
+           return Optional.empty();
+       }
+    }
+
+    public static synchronized Warehouse getInstance(String string) {
+        if (single_instance == null) {
+            single_instance = new Warehouse();
+        }
+        return single_instance;
+    }
+
+
+    public Map<Product, Category> getProductsGroupedByCategories() {
+        if(products == null || products.isEmpty()){
+            return Collections.emptyMap();
+        }
+       return Collections.emptyMap();
+    }
+
+    public void updateProductPrice(UUID id, BigDecimal newPrice){
+        for(Product product : products){
+            if (product.uuid == id){
+
+            }
+        }
+    }
+
+    public List<Perishable> expiredProducts() {
+        return null;
+    }
+}
+
+/*
+getInstance(String name) returns the same instance per unique name.
+addProduct(Product): throw IllegalArgumentException("Product cannot be null.") if null.
+getProducts(): return an unmodifiable copy.
+getProductById(UUID): return Optional.
+updateProductPrice(UUID, BigDecimal): when not found, throw NoSuchElementException("Product not found with id: "). Also track changed products in getChangedProducts().
+expiredProducts(): return List that are expired.
+shippableProducts(): return List from stored products.
+remove(UUID): remove the matching product if present.
+ */
diff --git a/src/main/java/com/example/WarehouseAnalyzer.java b/src/main/java/com/example/WarehouseAnalyzer.java
index 1779fc33..f975c517 100644
--- a/src/main/java/com/example/WarehouseAnalyzer.java
+++ b/src/main/java/com/example/WarehouseAnalyzer.java
@@ -145,6 +145,9 @@ public Map<Category, BigDecimal> calculateWeightedAveragePriceByCategory() {
      * @param standardDeviations threshold in standard deviations (e.g., 2.0)
      * @return list of products considered outliers
      */
+
+    //Denna är fel ***********************
+
     public List<Product> findPriceOutliers(double standardDeviations) {
         List<Product> products = warehouse.getProducts();
         int n = products.size();

From d7da0be11e299f5c516327986e0d349fed2715ee Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Mon, 20 Oct 2025 10:58:14 +0200
Subject: [PATCH 04/17] Constructed Category

---
 src/main/java/com/example/Category.java | 28 ++++++++++++++-----------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/main/java/com/example/Category.java b/src/main/java/com/example/Category.java
index d20d772c..e326bbf4 100644
--- a/src/main/java/com/example/Category.java
+++ b/src/main/java/com/example/Category.java
@@ -1,31 +1,35 @@
 package com.example;
 
+import java.util.HashMap;
+
 public class Category {
-    static String name;
+    public String name;
+    static HashMap<String, Category> categories = new HashMap<String, Category>();
 
     private Category(String categoryName) {
+        name = categoryName;
+
+        name = name.substring(0, 1).toUpperCase()
+                + name.substring(1).toLowerCase();
 
     }
 
     public static Category of(String name) {
-        if (name == null || name.isEmpty()) {
-            throw new IllegalArgumentException("Category name cannot be null or empty");
-        }
-        name = name;
+        if (name == null) {
+            throw new IllegalArgumentException("Category name can't be null");
+        } else if (name.isBlank())
+            throw new IllegalArgumentException("Category name can't be blank");
 
-        name = name.substring(0, 1).toUpperCase()
-                + name.substring(1).toLowerCase();
+        if (categories.containsKey(name))
+                return categories.get(name);
 
-        return new Category(name);
+        categories.put(name, new Category(name));
+        return categories.get(name);
 
     }
 
     public String getName() {
         return name;
     }
-
 }
 
-/*
-Cache/flyweight: return the same instance for the same normalized name.
- */

From d654187f9aea6570b86bbb8b3970890516345e7f Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Mon, 20 Oct 2025 11:06:51 +0200
Subject: [PATCH 05/17] Constructed ElectronicsProduct and added supers

---
 .../java/com/example/ElectronicsProduct.java     | 16 ++++++++++++++++
 src/main/java/com/example/FoodProduct.java       |  1 +
 src/main/java/com/example/Perishable.java        |  4 ++++
 src/main/java/com/example/Product.java           |  7 +++++++
 4 files changed, 28 insertions(+)

diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
index 9b0fb3b8..72868d99 100644
--- a/src/main/java/com/example/ElectronicsProduct.java
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -3,8 +3,24 @@
 import java.math.BigDecimal;
 import java.util.UUID;
 
+/*
+Implements Shippable.
+productDetails() should look like: "Electronics: Laptop, Warranty: 24 months".
+Shipping rule: base 79, add 49 if weight > 5.0 kg.
+ */
+
 public class ElectronicsProduct extends Product {
+    int warrantyMonths;
+    BigDecimal weight;
+
+
     public ElectronicsProduct(UUID id, String name, Category category, BigDecimal price, int warranty, BigDecimal weight) {
+        super(id, name, category, price);
+        this.warrantyMonths = warranty;
+        if (warrantyMonths < 0)
+            throw new IllegalArgumentException("Warranty months cannot be negative.");
+        this.weight = weight;
+
     }
 
     @Override
diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
index e6ed6b1a..8407e7ad 100644
--- a/src/main/java/com/example/FoodProduct.java
+++ b/src/main/java/com/example/FoodProduct.java
@@ -9,6 +9,7 @@ public class FoodProduct extends Product implements Perishables, Shippable {
     public BigDecimal weight;
 
     public FoodProduct(UUID id, String name, Category category, BigDecimal price, LocalDate expirationDate, BigDecimal weight) {
+        super(id, name, category, price);
 
     }
 
diff --git a/src/main/java/com/example/Perishable.java b/src/main/java/com/example/Perishable.java
index e31cc191..b4bf7ef3 100644
--- a/src/main/java/com/example/Perishable.java
+++ b/src/main/java/com/example/Perishable.java
@@ -5,6 +5,10 @@
 import java.util.UUID;
 
 public class Perishable extends Product{
+    public Perishable(UUID uuid, String name, Category category, BigDecimal price) {
+        super(uuid, name, category, price);
+    }
+
     public LocalDate expirationDate() {
         return LocalDate.now();
     }
diff --git a/src/main/java/com/example/Product.java b/src/main/java/com/example/Product.java
index 50adde73..97529423 100644
--- a/src/main/java/com/example/Product.java
+++ b/src/main/java/com/example/Product.java
@@ -11,6 +11,13 @@ public abstract class Product implements Perishables {
     Category category;
     BigDecimal price;
 
+    public Product(UUID uuid, String name, Category category, BigDecimal price) {
+        this.uuid = uuid;
+        this.name = name;
+        this.category = category;
+        this.price = price;
+    }
+
 
     public BigDecimal price() {
         return price;

From f2054b2084712289db2819087bdbb8cd2d960701 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Mon, 20 Oct 2025 12:38:39 +0200
Subject: [PATCH 06/17] Fully Constructed FoodProduct

---
 src/main/java/com/example/FoodProduct.java | 24 +++++++++-------------
 src/main/java/com/example/Product.java     |  3 +++
 2 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
index 8407e7ad..3647fa0e 100644
--- a/src/main/java/com/example/FoodProduct.java
+++ b/src/main/java/com/example/FoodProduct.java
@@ -10,40 +10,36 @@ public class FoodProduct extends Product implements Perishables, Shippable {
 
     public FoodProduct(UUID id, String name, Category category, BigDecimal price, LocalDate expirationDate, BigDecimal weight) {
         super(id, name, category, price);
+        this.expirationDate = expirationDate;
+        if (weight.compareTo(BigDecimal.ZERO) < 0)
+            throw new IllegalArgumentException("Weight cannot be negative.");
+        this.weight = weight;
 
     }
 
 
     @Override
     public BigDecimal getPrice() {
-        return null;
+        return price;
     }
 
     @Override
     public UUID uuid() {
-        return null;
+        return uuid;
     }
 
     @Override
     public String productDetails() {
-        return "";
+        return "Food: " + category + ", Expires: " + expirationDate;
     }
 
     @Override
     public double weight() {
-        return 0;
+        return weight.doubleValue();
     }
 
     @Override
     public BigDecimal calculateShippingCost() {
-        return null;
+        return weight.multiply(BigDecimal.valueOf(50));
     }
-}
-
-/*
-Implements Perishable and Shippable.
-Fields: LocalDate expirationDate, BigDecimal weight (kg).
-Validations: negative price -> IllegalArgumentException("Price cannot be negative."); negative weight -> IllegalArgumentException("Weight cannot be negative.").
-productDetails() should look like: "Food: Milk, Expires: 2025-12-24".
-Shipping rule: cost = weight * 50.
- */
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/src/main/java/com/example/Product.java b/src/main/java/com/example/Product.java
index 97529423..b80505f4 100644
--- a/src/main/java/com/example/Product.java
+++ b/src/main/java/com/example/Product.java
@@ -15,6 +15,9 @@ public Product(UUID uuid, String name, Category category, BigDecimal price) {
         this.uuid = uuid;
         this.name = name;
         this.category = category;
+        if(price.compareTo(BigDecimal.ZERO) < 0)
+            throw new IllegalArgumentException("Price cannot be negative.");
+
         this.price = price;
     }
 

From f20a2fd44a9d8ecdd19f6080528fc8b8666c843c Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Tue, 21 Oct 2025 09:08:30 +0200
Subject: [PATCH 07/17] Added simpleton constructor for Warehouse

---
 src/main/java/com/example/Warehouse.java | 60 +++++++++++++++---------
 1 file changed, 38 insertions(+), 22 deletions(-)

diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 9a69d95f..28299deb 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -4,11 +4,16 @@
 import java.util.*;
 
 public class Warehouse {
-    List<Product> products;
-    List<Shippable> shippables;
-
-    private static Warehouse single_instance = null;
-    public String instanceName;
+    List<Product> products = new ArrayList<>();
+    List<Shippable> shippables = new ArrayList<>();
+    List<Perishable> perishables = new ArrayList<>();
+    static HashMap<String, Warehouse> warehouses = new HashMap<>();
+
+    private Warehouse() {
+        this.products = new ArrayList<>();
+        this.shippables = new ArrayList<>();
+        this.perishables = new ArrayList<>();
+    }
 
     public List<Product> getProducts(){
         return products;
@@ -27,6 +32,8 @@ public boolean isEmpty(){
     }
 
     public void addProduct(Product product){
+        if (product == null)
+            throw new IllegalArgumentException("Product cannot be null.");
         products.add(product);
     }
 
@@ -38,23 +45,28 @@ public void remove(UUID id){
     }
 
     public Optional<Product> getProductById(UUID id){
-       var temp = products.stream()
-               .filter(product -> product.uuid == id)
-               .findFirst()
-               .isEmpty();
-
-       if(temp){
-           return Optional.empty();
-       } else {
+       if (products.isEmpty())
            return Optional.empty();
-       }
+
+        return products.stream()
+                .filter(p -> p.uuid == id)
+                .findFirst();
+
+
     }
 
     public static synchronized Warehouse getInstance(String string) {
-        if (single_instance == null) {
-            single_instance = new Warehouse();
-        }
-        return single_instance;
+        if (!warehouses.containsKey(string)) {
+            warehouses.put(string, new Warehouse());
+            return warehouses.get(string);
+        }else
+            return warehouses.get(string);
+    }
+
+    public static synchronized Warehouse getInstance() {
+        if(!warehouses.containsKey("default"))
+            warehouses.put("default", new  Warehouse());
+        return warehouses.get("default");
     }
 
 
@@ -66,11 +78,15 @@ public Map<Product, Category> getProductsGroupedByCategories() {
     }
 
     public void updateProductPrice(UUID id, BigDecimal newPrice){
-        for(Product product : products){
-            if (product.uuid == id){
 
-            }
-        }
+        var product = getProductById(id);
+
+        if(product.isPresent())
+            product.get().setPrice(newPrice);
+        else
+            throw new NoSuchElementException("Product not found with id:" + id);
+
+
     }
 
     public List<Perishable> expiredProducts() {

From 9a884661d366eb1c436ecf9d4280ab447a25fee8 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Tue, 21 Oct 2025 12:35:11 +0200
Subject: [PATCH 08/17] Propperly implimented getProductsGroupedByCategories
 for Warehouse, still minor bug

---
 src/main/java/com/example/Warehouse.java | 26 ++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 28299deb..5b4e77b6 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -13,6 +13,7 @@ private Warehouse() {
         this.products = new ArrayList<>();
         this.shippables = new ArrayList<>();
         this.perishables = new ArrayList<>();
+
     }
 
     public List<Product> getProducts(){
@@ -38,10 +39,7 @@ public void addProduct(Product product){
     }
 
     public void remove(UUID id){
-        for(Product product : products){
-            if (product.uuid == id)
-                products.remove(product);
-        }
+        products.removeIf(product -> product.uuid == id);
     }
 
     public Optional<Product> getProductById(UUID id){
@@ -70,11 +68,27 @@ public static synchronized Warehouse getInstance() {
     }
 
 
-    public Map<Product, Category> getProductsGroupedByCategories() {
+    public Map<Category, List<Product>> getProductsGroupedByCategories() {
         if(products == null || products.isEmpty()){
             return Collections.emptyMap();
         }
-       return Collections.emptyMap();
+
+        HashMap<Category, List<Product>> result = new HashMap<>();
+
+        var tempMap = Category.categories.entrySet();
+
+        for(var category : tempMap){
+            List<Product> tempList = new ArrayList<>();
+
+            products.stream()
+                    .filter(element -> element.category.equals(category.getValue()))
+                    .forEach(tempList::add);
+
+            result.put(category.getValue(), tempList);
+        }
+
+        return result;
+
     }
 
     public void updateProductPrice(UUID id, BigDecimal newPrice){

From 3290fa0a9b44e0fc1eb3fa07f3c526aef50b0ad8 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Tue, 21 Oct 2025 13:28:10 +0200
Subject: [PATCH 09/17] Added clearing of the Category cashe clearing products,
 correctly formated productDetails in FoodProduct and ElectronicsProduct

---
 src/main/java/com/example/Category.java           | 4 ++++
 src/main/java/com/example/ElectronicsProduct.java | 2 +-
 src/main/java/com/example/FoodProduct.java        | 2 +-
 src/main/java/com/example/Warehouse.java          | 7 +++++--
 4 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/example/Category.java b/src/main/java/com/example/Category.java
index e326bbf4..2fa3d54d 100644
--- a/src/main/java/com/example/Category.java
+++ b/src/main/java/com/example/Category.java
@@ -28,6 +28,10 @@ public static Category of(String name) {
 
     }
 
+    public void clear(){
+        categories.clear();
+    }
+
     public String getName() {
         return name;
     }
diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
index 72868d99..d62c5451 100644
--- a/src/main/java/com/example/ElectronicsProduct.java
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -25,7 +25,7 @@ public ElectronicsProduct(UUID id, String name, Category category, BigDecimal pr
 
     @Override
     public String productDetails() {
-        return "";
+        return "Electronics: " + name + ", Warranty: " + warrantyMonths + " months";
     }
 
     @Override
diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
index 3647fa0e..6d74c26e 100644
--- a/src/main/java/com/example/FoodProduct.java
+++ b/src/main/java/com/example/FoodProduct.java
@@ -30,7 +30,7 @@ public UUID uuid() {
 
     @Override
     public String productDetails() {
-        return "Food: " + category + ", Expires: " + expirationDate;
+        return "Food: " + name + ", Expires: " + expirationDate;
     }
 
     @Override
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 5b4e77b6..2e0161de 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -17,7 +17,7 @@ private Warehouse() {
     }
 
     public List<Product> getProducts(){
-        return products;
+        return Collections.unmodifiableList(products);
     }
 
     public List<Shippable> shippableProducts() {
@@ -26,6 +26,7 @@ public List<Shippable> shippableProducts() {
 
     public void clearProducts(){
         products.clear();
+        Category.categories.clear();
     }
 
     public boolean isEmpty(){
@@ -35,7 +36,10 @@ public boolean isEmpty(){
     public void addProduct(Product product){
         if (product == null)
             throw new IllegalArgumentException("Product cannot be null.");
+        if (getProductById(product.uuid).isPresent())
+            throw new IllegalArgumentException("Product with that id already exists, use updateProduct for updates.");
         products.add(product);
+
     }
 
     public void remove(UUID id){
@@ -67,7 +71,6 @@ public static synchronized Warehouse getInstance() {
         return warehouses.get("default");
     }
 
-
     public Map<Category, List<Product>> getProductsGroupedByCategories() {
         if(products == null || products.isEmpty()){
             return Collections.emptyMap();

From 15a56b8aeafe5c16b1627757248b0d4ea5d9bedb Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Tue, 21 Oct 2025 15:01:30 +0200
Subject: [PATCH 10/17] Fixed the Perishable and Shippable interface

---
 .../java/com/example/ElectronicsProduct.java  | 19 ++++++++----
 src/main/java/com/example/FoodProduct.java    | 11 +++----
 src/main/java/com/example/Perishable.java     | 26 ++++------------
 .../java/com/example/Perishableclass.java     | 30 +++++++++++++++++++
 src/main/java/com/example/Perishables.java    | 13 --------
 src/main/java/com/example/Product.java        |  2 +-
 src/main/java/com/example/Shippable.java      |  1 +
 src/main/java/com/example/Warehouse.java      | 11 +++++--
 8 files changed, 66 insertions(+), 47 deletions(-)
 create mode 100644 src/main/java/com/example/Perishableclass.java
 delete mode 100644 src/main/java/com/example/Perishables.java

diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
index d62c5451..8171a704 100644
--- a/src/main/java/com/example/ElectronicsProduct.java
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -5,13 +5,14 @@
 
 /*
 Implements Shippable.
-productDetails() should look like: "Electronics: Laptop, Warranty: 24 months".
 Shipping rule: base 79, add 49 if weight > 5.0 kg.
  */
 
-public class ElectronicsProduct extends Product {
+public class ElectronicsProduct extends Product implements Shippable {
     int warrantyMonths;
     BigDecimal weight;
+    BigDecimal basePrice = BigDecimal.valueOf(79);
+    BigDecimal addPrice = BigDecimal.valueOf(49);
 
 
     public ElectronicsProduct(UUID id, String name, Category category, BigDecimal price, int warranty, BigDecimal weight) {
@@ -29,12 +30,20 @@ public String productDetails() {
     }
 
     @Override
-    public BigDecimal getPrice() {
+    public UUID uuid() {
         return null;
     }
 
     @Override
-    public UUID uuid() {
-        return null;
+    public double weight() {
+        return weight.doubleValue();
+    }
+
+    @Override
+    public BigDecimal calculateShippingCost() {
+        if(weight.intValue() >= 5)
+            return basePrice.add(addPrice);
+        else
+            return basePrice;
     }
 }
diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
index 6d74c26e..d03028cc 100644
--- a/src/main/java/com/example/FoodProduct.java
+++ b/src/main/java/com/example/FoodProduct.java
@@ -4,7 +4,7 @@
 import java.time.LocalDate;
 import java.util.UUID;
 
-public class FoodProduct extends Product implements Perishables, Shippable {
+public class FoodProduct extends Product implements Perishable, Shippable {
     public LocalDate expirationDate;
     public BigDecimal weight;
 
@@ -18,16 +18,17 @@ public FoodProduct(UUID id, String name, Category category, BigDecimal price, Lo
     }
 
 
-    @Override
-    public BigDecimal getPrice() {
-        return price;
-    }
 
     @Override
     public UUID uuid() {
         return uuid;
     }
 
+    @Override
+    public LocalDate expirationDate() {
+        return expirationDate;
+    }
+
     @Override
     public String productDetails() {
         return "Food: " + name + ", Expires: " + expirationDate;
diff --git a/src/main/java/com/example/Perishable.java b/src/main/java/com/example/Perishable.java
index b4bf7ef3..ab44bf71 100644
--- a/src/main/java/com/example/Perishable.java
+++ b/src/main/java/com/example/Perishable.java
@@ -1,30 +1,14 @@
 package com.example;
 
-import java.math.BigDecimal;
 import java.time.LocalDate;
 import java.util.UUID;
 
-public class Perishable extends Product{
-    public Perishable(UUID uuid, String name, Category category, BigDecimal price) {
-        super(uuid, name, category, price);
-    }
-
-    public LocalDate expirationDate() {
-        return LocalDate.now();
-    }
+interface Perishable {
+    UUID uuid();
+    LocalDate expirationDate();
 
-    @Override
-    public String productDetails() {
-        return "";
+    default Boolean isExpired(Perishable perishable) {
+        return LocalDate.now().isAfter(perishable.expirationDate());
     }
 
-    @Override
-    public BigDecimal getPrice() {
-        return null;
-    }
-
-    @Override
-    public UUID uuid() {
-        return null;
-    }
 }
diff --git a/src/main/java/com/example/Perishableclass.java b/src/main/java/com/example/Perishableclass.java
new file mode 100644
index 00000000..e120cc59
--- /dev/null
+++ b/src/main/java/com/example/Perishableclass.java
@@ -0,0 +1,30 @@
+//package com.example;
+//
+//import java.math.BigDecimal;
+//import java.time.LocalDate;
+//import java.util.UUID;
+//
+//public class Perishable extends Product{
+//    public Perishable(UUID uuid, String name, Category category, BigDecimal price) {
+//        super(uuid, name, category, price);
+//    }
+//
+//    public LocalDate expirationDate() {
+//        return LocalDate.now();
+//    }
+//
+//    @Override
+//    public String productDetails() {
+//        return "";
+//    }
+//
+//    @Override
+//    public BigDecimal getPrice() {
+//        return null;
+//    }
+//
+//    @Override
+//    public UUID uuid() {
+//        return null;
+//    }
+//}
diff --git a/src/main/java/com/example/Perishables.java b/src/main/java/com/example/Perishables.java
deleted file mode 100644
index 6e5151c1..00000000
--- a/src/main/java/com/example/Perishables.java
+++ /dev/null
@@ -1,13 +0,0 @@
-package com.example;
-
-import java.math.BigDecimal;
-import java.time.LocalDate;
-import java.util.UUID;
-
-public interface Perishables {
-    LocalDate expirationDate = null;
-    public BigDecimal getPrice();
-
-
-    UUID uuid();
-}
diff --git a/src/main/java/com/example/Product.java b/src/main/java/com/example/Product.java
index b80505f4..79f517ba 100644
--- a/src/main/java/com/example/Product.java
+++ b/src/main/java/com/example/Product.java
@@ -5,7 +5,7 @@
 
 
 
-public abstract class Product implements Perishables {
+public abstract class Product {
     UUID uuid;
     String name;
     Category category;
diff --git a/src/main/java/com/example/Shippable.java b/src/main/java/com/example/Shippable.java
index eb9fd2c4..fdd04729 100644
--- a/src/main/java/com/example/Shippable.java
+++ b/src/main/java/com/example/Shippable.java
@@ -5,4 +5,5 @@
 public interface Shippable {
     double weight();
     BigDecimal calculateShippingCost();
+
 }
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 2e0161de..5f3b93dd 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -7,6 +7,7 @@ public class Warehouse {
     List<Product> products = new ArrayList<>();
     List<Shippable> shippables = new ArrayList<>();
     List<Perishable> perishables = new ArrayList<>();
+    List<Perishable> expired = new ArrayList<>();
     static HashMap<String, Warehouse> warehouses = new HashMap<>();
 
     private Warehouse() {
@@ -27,6 +28,7 @@ public List<Shippable> shippableProducts() {
     public void clearProducts(){
         products.clear();
         Category.categories.clear();
+        shippables.clear();
     }
 
     public boolean isEmpty(){
@@ -39,7 +41,10 @@ public void addProduct(Product product){
         if (getProductById(product.uuid).isPresent())
             throw new IllegalArgumentException("Product with that id already exists, use updateProduct for updates.");
         products.add(product);
-
+        if(product instanceof Shippable)
+            shippables.add((Shippable) product);
+        if(product instanceof Perishable)
+            perishables.add((Perishable) product);
     }
 
     public void remove(UUID id){
@@ -107,7 +112,9 @@ public void updateProductPrice(UUID id, BigDecimal newPrice){
     }
 
     public List<Perishable> expiredProducts() {
-        return null;
+        return perishables.stream()
+                .filter(perishable -> perishable.isExpired(perishable))
+                .toList();
     }
 }
 

From fa78ea3c008ce77433ce126b8bad1d75dfaa717c Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Tue, 21 Oct 2025 15:05:07 +0200
Subject: [PATCH 11/17] Cleaned up redundancies.

---
 src/main/java/com/example/Category.java    |  6 +-----
 src/main/java/com/example/FoodProduct.java |  7 -------
 src/main/java/com/example/Perishable.java  |  2 --
 src/main/java/com/example/Warehouse.java   | 12 +++++-------
 4 files changed, 6 insertions(+), 21 deletions(-)

diff --git a/src/main/java/com/example/Category.java b/src/main/java/com/example/Category.java
index 2fa3d54d..8d3b83e4 100644
--- a/src/main/java/com/example/Category.java
+++ b/src/main/java/com/example/Category.java
@@ -4,7 +4,7 @@
 
 public class Category {
     public String name;
-    static HashMap<String, Category> categories = new HashMap<String, Category>();
+    static HashMap<String, Category> categories = new HashMap<>();
 
     private Category(String categoryName) {
         name = categoryName;
@@ -28,10 +28,6 @@ public static Category of(String name) {
 
     }
 
-    public void clear(){
-        categories.clear();
-    }
-
     public String getName() {
         return name;
     }
diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
index d03028cc..17478094 100644
--- a/src/main/java/com/example/FoodProduct.java
+++ b/src/main/java/com/example/FoodProduct.java
@@ -17,13 +17,6 @@ public FoodProduct(UUID id, String name, Category category, BigDecimal price, Lo
 
     }
 
-
-
-    @Override
-    public UUID uuid() {
-        return uuid;
-    }
-
     @Override
     public LocalDate expirationDate() {
         return expirationDate;
diff --git a/src/main/java/com/example/Perishable.java b/src/main/java/com/example/Perishable.java
index ab44bf71..aa87b378 100644
--- a/src/main/java/com/example/Perishable.java
+++ b/src/main/java/com/example/Perishable.java
@@ -1,10 +1,8 @@
 package com.example;
 
 import java.time.LocalDate;
-import java.util.UUID;
 
 interface Perishable {
-    UUID uuid();
     LocalDate expirationDate();
 
     default Boolean isExpired(Perishable perishable) {
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 5f3b93dd..11256752 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -4,10 +4,9 @@
 import java.util.*;
 
 public class Warehouse {
-    List<Product> products = new ArrayList<>();
-    List<Shippable> shippables = new ArrayList<>();
-    List<Perishable> perishables = new ArrayList<>();
-    List<Perishable> expired = new ArrayList<>();
+    List<Product> products;
+    List<Shippable> shippables;
+    List<Perishable> perishables;
     static HashMap<String, Warehouse> warehouses = new HashMap<>();
 
     private Warehouse() {
@@ -65,9 +64,8 @@ public Optional<Product> getProductById(UUID id){
     public static synchronized Warehouse getInstance(String string) {
         if (!warehouses.containsKey(string)) {
             warehouses.put(string, new Warehouse());
-            return warehouses.get(string);
-        }else
-            return warehouses.get(string);
+        }
+        return warehouses.get(string);
     }
 
     public static synchronized Warehouse getInstance() {

From ea7a98a54e0731309856e70b49458d7d08b5a7df Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Thu, 23 Oct 2025 10:52:22 +0200
Subject: [PATCH 12/17] Changed products from a list to a hashmap

---
 .../java/com/example/ElectronicsProduct.java  |  9 ++++----
 src/main/java/com/example/Warehouse.java      | 22 ++++++++-----------
 .../java/com/example/WarehouseAnalyzer.java   |  1 -
 3 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
index 8171a704..d4bc8e15 100644
--- a/src/main/java/com/example/ElectronicsProduct.java
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -24,14 +24,13 @@ public ElectronicsProduct(UUID id, String name, Category category, BigDecimal pr
 
     }
 
-    @Override
-    public String productDetails() {
-        return "Electronics: " + name + ", Warranty: " + warrantyMonths + " months";
+    public int getWarrantyMonths() {
+        return warrantyMonths;
     }
 
     @Override
-    public UUID uuid() {
-        return null;
+    public String productDetails() {
+        return "Electronics: " + name + ", Warranty: " + warrantyMonths + " months";
     }
 
     @Override
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 11256752..b9061e02 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -4,20 +4,19 @@
 import java.util.*;
 
 public class Warehouse {
-    List<Product> products;
+    HashMap<UUID, Product> products;
     List<Shippable> shippables;
     List<Perishable> perishables;
     static HashMap<String, Warehouse> warehouses = new HashMap<>();
 
     private Warehouse() {
-        this.products = new ArrayList<>();
+        this.products = new HashMap<>();
         this.shippables = new ArrayList<>();
         this.perishables = new ArrayList<>();
-
     }
 
     public List<Product> getProducts(){
-        return Collections.unmodifiableList(products);
+        return List.copyOf(products.values());
     }
 
     public List<Shippable> shippableProducts() {
@@ -28,6 +27,7 @@ public void clearProducts(){
         products.clear();
         Category.categories.clear();
         shippables.clear();
+        perishables.clear();
     }
 
     public boolean isEmpty(){
@@ -39,7 +39,7 @@ public void addProduct(Product product){
             throw new IllegalArgumentException("Product cannot be null.");
         if (getProductById(product.uuid).isPresent())
             throw new IllegalArgumentException("Product with that id already exists, use updateProduct for updates.");
-        products.add(product);
+        products.put(product.uuid, product);
         if(product instanceof Shippable)
             shippables.add((Shippable) product);
         if(product instanceof Perishable)
@@ -47,18 +47,13 @@ public void addProduct(Product product){
     }
 
     public void remove(UUID id){
-        products.removeIf(product -> product.uuid == id);
+        products.remove(id);
     }
 
     public Optional<Product> getProductById(UUID id){
        if (products.isEmpty())
            return Optional.empty();
-
-        return products.stream()
-                .filter(p -> p.uuid == id)
-                .findFirst();
-
-
+        return (Optional.ofNullable(products.get(id)));
     }
 
     public static synchronized Warehouse getInstance(String string) {
@@ -82,11 +77,12 @@ public Map<Category, List<Product>> getProductsGroupedByCategories() {
         HashMap<Category, List<Product>> result = new HashMap<>();
 
         var tempMap = Category.categories.entrySet();
+        var productsList = new ArrayList<>(products.values());
 
         for(var category : tempMap){
             List<Product> tempList = new ArrayList<>();
 
-            products.stream()
+            productsList.stream()
                     .filter(element -> element.category.equals(category.getValue()))
                     .forEach(tempList::add);
 
diff --git a/src/main/java/com/example/WarehouseAnalyzer.java b/src/main/java/com/example/WarehouseAnalyzer.java
index f975c517..b6b67a32 100644
--- a/src/main/java/com/example/WarehouseAnalyzer.java
+++ b/src/main/java/com/example/WarehouseAnalyzer.java
@@ -146,7 +146,6 @@ public Map<Category, BigDecimal> calculateWeightedAveragePriceByCategory() {
      * @return list of products considered outliers
      */
 
-    //Denna är fel ***********************
 
     public List<Product> findPriceOutliers(double standardDeviations) {
         List<Product> products = warehouse.getProducts();

From a758d09b8cb9bdc844d256dfbb2b60e8e5ae3bc9 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Thu, 23 Oct 2025 11:24:29 +0200
Subject: [PATCH 13/17] Added getChangedProducts to track changed product
 prices

---
 .../java/com/example/Perishableclass.java     | 30 -------------------
 src/main/java/com/example/Warehouse.java      | 13 ++++++--
 2 files changed, 10 insertions(+), 33 deletions(-)
 delete mode 100644 src/main/java/com/example/Perishableclass.java

diff --git a/src/main/java/com/example/Perishableclass.java b/src/main/java/com/example/Perishableclass.java
deleted file mode 100644
index e120cc59..00000000
--- a/src/main/java/com/example/Perishableclass.java
+++ /dev/null
@@ -1,30 +0,0 @@
-//package com.example;
-//
-//import java.math.BigDecimal;
-//import java.time.LocalDate;
-//import java.util.UUID;
-//
-//public class Perishable extends Product{
-//    public Perishable(UUID uuid, String name, Category category, BigDecimal price) {
-//        super(uuid, name, category, price);
-//    }
-//
-//    public LocalDate expirationDate() {
-//        return LocalDate.now();
-//    }
-//
-//    @Override
-//    public String productDetails() {
-//        return "";
-//    }
-//
-//    @Override
-//    public BigDecimal getPrice() {
-//        return null;
-//    }
-//
-//    @Override
-//    public UUID uuid() {
-//        return null;
-//    }
-//}
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index b9061e02..54213228 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -1,6 +1,7 @@
 package com.example;
 
 import java.math.BigDecimal;
+import java.time.LocalDateTime;
 import java.util.*;
 
 public class Warehouse {
@@ -8,6 +9,7 @@ public class Warehouse {
     List<Shippable> shippables;
     List<Perishable> perishables;
     static HashMap<String, Warehouse> warehouses = new HashMap<>();
+    HashMap<Optional<Product>, HashMap<LocalDateTime, BigDecimal>> changedProducts = new HashMap<>();
 
     private Warehouse() {
         this.products = new HashMap<>();
@@ -94,15 +96,20 @@ public Map<Category, List<Product>> getProductsGroupedByCategories() {
     }
 
     public void updateProductPrice(UUID id, BigDecimal newPrice){
-
         var product = getProductById(id);
-
-        if(product.isPresent())
+        if(product.isPresent()) {
+            var tempMap = new HashMap<LocalDateTime, BigDecimal>();
+            tempMap.put(LocalDateTime.now(), product.get().price);
+            changedProducts.put(product, tempMap);
             product.get().setPrice(newPrice);
+        }
         else
             throw new NoSuchElementException("Product not found with id:" + id);
 
+    }
 
+    public Map<Optional<Product>, HashMap<LocalDateTime, BigDecimal>> getChangedProducts(){
+            return changedProducts;
     }
 
     public List<Perishable> expiredProducts() {

From f2ecb2a0ce3a35caa2fd6176840e40ef04d0f0e7 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Thu, 23 Oct 2025 11:29:19 +0200
Subject: [PATCH 14/17] Fixed calculateShippingCost in ElectronicsProduct

---
 src/main/java/com/example/ElectronicsProduct.java | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
index d4bc8e15..d52f5be8 100644
--- a/src/main/java/com/example/ElectronicsProduct.java
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -40,9 +40,8 @@ public double weight() {
 
     @Override
     public BigDecimal calculateShippingCost() {
-        if(weight.intValue() >= 5)
-            return basePrice.add(addPrice);
-        else
-            return basePrice;
+        return (weight.compareTo(BigDecimal.valueOf(5.0)) >= 0)
+            ? basePrice.add(addPrice)
+            : basePrice;
     }
 }

From 61e66b0871d23e6f85f9e1dac8b19c31e8486242 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Thu, 23 Oct 2025 11:31:21 +0200
Subject: [PATCH 15/17] Simplified isExpired in Perishable

---
 src/main/java/com/example/Perishable.java | 4 ++--
 src/main/java/com/example/Warehouse.java  | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/main/java/com/example/Perishable.java b/src/main/java/com/example/Perishable.java
index aa87b378..09cefc58 100644
--- a/src/main/java/com/example/Perishable.java
+++ b/src/main/java/com/example/Perishable.java
@@ -5,8 +5,8 @@
 interface Perishable {
     LocalDate expirationDate();
 
-    default Boolean isExpired(Perishable perishable) {
-        return LocalDate.now().isAfter(perishable.expirationDate());
+    default boolean isExpired() {
+        return LocalDate.now().isAfter(expirationDate());
     }
 
 }
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 54213228..290a3f28 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -114,7 +114,7 @@ public Map<Optional<Product>, HashMap<LocalDateTime, BigDecimal>> getChangedProd
 
     public List<Perishable> expiredProducts() {
         return perishables.stream()
-                .filter(perishable -> perishable.isExpired(perishable))
+                .filter(Perishable::isExpired)
                 .toList();
     }
 }

From 52c512237367a868067494cbd9f6677c61de3ff3 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Thu, 23 Oct 2025 13:09:15 +0200
Subject: [PATCH 16/17] Reconstructed findPriceOutliers with IQR

---
 .../java/com/example/WarehouseAnalyzer.java   | 46 +++++++++++++------
 1 file changed, 32 insertions(+), 14 deletions(-)

diff --git a/src/main/java/com/example/WarehouseAnalyzer.java b/src/main/java/com/example/WarehouseAnalyzer.java
index b6b67a32..54349ac5 100644
--- a/src/main/java/com/example/WarehouseAnalyzer.java
+++ b/src/main/java/com/example/WarehouseAnalyzer.java
@@ -148,25 +148,43 @@ public Map<Category, BigDecimal> calculateWeightedAveragePriceByCategory() {
 
 
     public List<Product> findPriceOutliers(double standardDeviations) {
-        List<Product> products = warehouse.getProducts();
-        int n = products.size();
-        if (n == 0) return List.of();
-        double sum = products.stream().map(Product::price).mapToDouble(bd -> bd.doubleValue()).sum();
-        double mean = sum / n;
-        double variance = products.stream()
+        List<Product> productList = warehouse.getProducts();
+        List<BigDecimal> products = productList.stream()
                 .map(Product::price)
-                .mapToDouble(bd -> Math.pow(bd.doubleValue() - mean, 2))
-                .sum() / n;
-        double std = Math.sqrt(variance);
-        double threshold = standardDeviations * std;
+                .sorted()
+                .toList();
+
+        var Q1 = getPercentile(products, 25);
+        var Q3 = getPercentile(products, 75);
+
+        var IQR = Q3.doubleValue()-Q1.doubleValue();
+        var lowRange = Q1.doubleValue()-standardDeviations*IQR;
+        var highRange = Q3.doubleValue()+standardDeviations*IQR;
+
         List<Product> outliers = new ArrayList<>();
-        for (Product p : products) {
-            double diff = Math.abs(p.price().doubleValue() - mean);
-            if (diff > threshold) outliers.add(p);
+        for(Product p : productList){
+            if((p.price.doubleValue()>highRange) || (p.price.doubleValue()<lowRange))
+                outliers.add(p);
         }
         return outliers;
     }
-    
+
+
+    static <T extends Comparable<T>> T getPercentile(Collection<T> input, double percentile) {
+        if (input == null || input.isEmpty()) {
+            throw new IllegalArgumentException("The input dataset cannot be null or empty.");
+        }
+        if (percentile < 0 || percentile > 100) {
+            throw new IllegalArgumentException("Percentile must be between 0 and 100 inclusive.");
+        }
+        List<T> sortedList = input.stream()
+                .sorted()
+                .collect(Collectors.toList());
+
+        int rank = percentile == 0 ? 1 : (int) Math.ceil(percentile / 100.0 * input.size());
+        return sortedList.get(rank - 1);
+    }
+
     /**
      * Groups all shippable products into ShippingGroup buckets such that each group's total weight
      * does not exceed the provided maximum. The goal is to minimize the number of groups and/or total

From 6757f3c2ce31f832c99580680852216a42c8e709 Mon Sep 17 00:00:00 2001
From: Samuel Fjellet <229708690+Samuel-Fjellet@users.noreply.github.com>
Date: Thu, 23 Oct 2025 13:28:09 +0200
Subject: [PATCH 17/17] Final cleanup

---
 src/main/java/com/example/Category.java       |  5 ----
 .../java/com/example/ElectronicsProduct.java  |  7 ------
 src/main/java/com/example/FoodProduct.java    |  1 -
 src/main/java/com/example/Perishable.java     |  2 --
 src/main/java/com/example/Product.java        |  5 ----
 src/main/java/com/example/Shippable.java      |  3 +--
 src/main/java/com/example/Warehouse.java      | 23 +++----------------
 7 files changed, 4 insertions(+), 42 deletions(-)

diff --git a/src/main/java/com/example/Category.java b/src/main/java/com/example/Category.java
index 8d3b83e4..6b9632f7 100644
--- a/src/main/java/com/example/Category.java
+++ b/src/main/java/com/example/Category.java
@@ -8,10 +8,8 @@ public class Category {
 
     private Category(String categoryName) {
         name = categoryName;
-
         name = name.substring(0, 1).toUpperCase()
                 + name.substring(1).toLowerCase();
-
     }
 
     public static Category of(String name) {
@@ -19,13 +17,10 @@ public static Category of(String name) {
             throw new IllegalArgumentException("Category name can't be null");
         } else if (name.isBlank())
             throw new IllegalArgumentException("Category name can't be blank");
-
         if (categories.containsKey(name))
                 return categories.get(name);
-
         categories.put(name, new Category(name));
         return categories.get(name);
-
     }
 
     public String getName() {
diff --git a/src/main/java/com/example/ElectronicsProduct.java b/src/main/java/com/example/ElectronicsProduct.java
index d52f5be8..17d36747 100644
--- a/src/main/java/com/example/ElectronicsProduct.java
+++ b/src/main/java/com/example/ElectronicsProduct.java
@@ -3,25 +3,18 @@
 import java.math.BigDecimal;
 import java.util.UUID;
 
-/*
-Implements Shippable.
-Shipping rule: base 79, add 49 if weight > 5.0 kg.
- */
-
 public class ElectronicsProduct extends Product implements Shippable {
     int warrantyMonths;
     BigDecimal weight;
     BigDecimal basePrice = BigDecimal.valueOf(79);
     BigDecimal addPrice = BigDecimal.valueOf(49);
 
-
     public ElectronicsProduct(UUID id, String name, Category category, BigDecimal price, int warranty, BigDecimal weight) {
         super(id, name, category, price);
         this.warrantyMonths = warranty;
         if (warrantyMonths < 0)
             throw new IllegalArgumentException("Warranty months cannot be negative.");
         this.weight = weight;
-
     }
 
     public int getWarrantyMonths() {
diff --git a/src/main/java/com/example/FoodProduct.java b/src/main/java/com/example/FoodProduct.java
index 17478094..c50b8f3a 100644
--- a/src/main/java/com/example/FoodProduct.java
+++ b/src/main/java/com/example/FoodProduct.java
@@ -14,7 +14,6 @@ public FoodProduct(UUID id, String name, Category category, BigDecimal price, Lo
         if (weight.compareTo(BigDecimal.ZERO) < 0)
             throw new IllegalArgumentException("Weight cannot be negative.");
         this.weight = weight;
-
     }
 
     @Override
diff --git a/src/main/java/com/example/Perishable.java b/src/main/java/com/example/Perishable.java
index 09cefc58..adeba099 100644
--- a/src/main/java/com/example/Perishable.java
+++ b/src/main/java/com/example/Perishable.java
@@ -4,9 +4,7 @@
 
 interface Perishable {
     LocalDate expirationDate();
-
     default boolean isExpired() {
         return LocalDate.now().isAfter(expirationDate());
     }
-
 }
diff --git a/src/main/java/com/example/Product.java b/src/main/java/com/example/Product.java
index 79f517ba..ba422d27 100644
--- a/src/main/java/com/example/Product.java
+++ b/src/main/java/com/example/Product.java
@@ -3,8 +3,6 @@
 import java.math.BigDecimal;
 import java.util.UUID;
 
-
-
 public abstract class Product {
     UUID uuid;
     String name;
@@ -17,11 +15,9 @@ public Product(UUID uuid, String name, Category category, BigDecimal price) {
         this.category = category;
         if(price.compareTo(BigDecimal.ZERO) < 0)
             throw new IllegalArgumentException("Price cannot be negative.");
-
         this.price = price;
     }
 
-
     public BigDecimal price() {
         return price;
     }
@@ -43,5 +39,4 @@ public Category category() {
     }
 
     public abstract String productDetails();
-
 }
diff --git a/src/main/java/com/example/Shippable.java b/src/main/java/com/example/Shippable.java
index fdd04729..6b1b2e49 100644
--- a/src/main/java/com/example/Shippable.java
+++ b/src/main/java/com/example/Shippable.java
@@ -3,7 +3,6 @@
 import java.math.BigDecimal;
 
 public interface Shippable {
-    double weight();
     BigDecimal calculateShippingCost();
-
+    double weight();
 }
diff --git a/src/main/java/com/example/Warehouse.java b/src/main/java/com/example/Warehouse.java
index 290a3f28..33e6a417 100644
--- a/src/main/java/com/example/Warehouse.java
+++ b/src/main/java/com/example/Warehouse.java
@@ -5,16 +5,17 @@
 import java.util.*;
 
 public class Warehouse {
+    static HashMap<String, Warehouse> warehouses = new HashMap<>();
     HashMap<UUID, Product> products;
     List<Shippable> shippables;
     List<Perishable> perishables;
-    static HashMap<String, Warehouse> warehouses = new HashMap<>();
-    HashMap<Optional<Product>, HashMap<LocalDateTime, BigDecimal>> changedProducts = new HashMap<>();
+    HashMap<Optional<Product>, HashMap<LocalDateTime, BigDecimal>> changedProducts;
 
     private Warehouse() {
         this.products = new HashMap<>();
         this.shippables = new ArrayList<>();
         this.perishables = new ArrayList<>();
+        this.changedProducts = new HashMap<>();
     }
 
     public List<Product> getProducts(){
@@ -75,24 +76,17 @@ public Map<Category, List<Product>> getProductsGroupedByCategories() {
         if(products == null || products.isEmpty()){
             return Collections.emptyMap();
         }
-
         HashMap<Category, List<Product>> result = new HashMap<>();
-
         var tempMap = Category.categories.entrySet();
         var productsList = new ArrayList<>(products.values());
-
         for(var category : tempMap){
             List<Product> tempList = new ArrayList<>();
-
             productsList.stream()
                     .filter(element -> element.category.equals(category.getValue()))
                     .forEach(tempList::add);
-
             result.put(category.getValue(), tempList);
         }
-
         return result;
-
     }
 
     public void updateProductPrice(UUID id, BigDecimal newPrice){
@@ -105,7 +99,6 @@ public void updateProductPrice(UUID id, BigDecimal newPrice){
         }
         else
             throw new NoSuchElementException("Product not found with id:" + id);
-
     }
 
     public Map<Optional<Product>, HashMap<LocalDateTime, BigDecimal>> getChangedProducts(){
@@ -119,13 +112,3 @@ public List<Perishable> expiredProducts() {
     }
 }
 
-/*
-getInstance(String name) returns the same instance per unique name.
-addProduct(Product): throw IllegalArgumentException("Product cannot be null.") if null.
-getProducts(): return an unmodifiable copy.
-getProductById(UUID): return Optional.
-updateProductPrice(UUID, BigDecimal): when not found, throw NoSuchElementException("Product not found with id: "). Also track changed products in getChangedProducts().
-expiredProducts(): return List that are expired.
-shippableProducts(): return List from stored products.
-remove(UUID): remove the matching product if present.
- */