Implement Iterator Design Pattern

Design Patterns/src/iterator/DinerMenu.java

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+package iterator;
+
+public class DinerMenu {
+    private static final int MAX_ITEMS = 6;
+    private int numberOfItems = 0;
+    private final MenuItem[] menuItems = new MenuItem[MAX_ITEMS];
+
+    public DinerMenu() {
+
+        addItem("Vegetarian BLT",
+                "(Fakin') Bacon with lettuce & tomato on whole wheat", true, 2.99);
+        addItem("BLT",
+                "Bacon with lettuce & tomato on whole wheat", false, 2.99);
+        addItem("Soup of the day",
+                "Soup of the day, with a side of potato salad", false, 3.29);
+        addItem("Hotdog",
+                "A hot dog, with saurkraut, relish, onions, topped with cheese",
+                false, 3.05);
+        addItem("Steamed Veggies and Brown Rice",
+                "Steamed vegetables over brown rice", true, 3.99);
+        addItem("Pasta",
+                "Spaghetti with Marinara Sauce, and a slice of sourdough bread",
+                true, 3.89);
+    }
+
+    public void addItem(String name, String description, boolean vegetarian, double price) {
+        if (numberOfItems < MAX_ITEMS) {
+            this.menuItems[numberOfItems++] = new MenuItem(name, description, vegetarian, price);
+        } else {
+            System.out.println("Sorry, menu is full! Can't add item to menu");
+        }
+    }
+
+/*
+    Note: Using iterator to get rid of this code
+    public MenuItem[] getMenuItems() {
+        return menuItems;
+    }
+*/
+
+    public Iterator createIterator() {
+        return new DinerMenuIterator(menuItems);
+    }
+}

Design Patterns/src/iterator/DinerMenuIterator.java

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+package iterator;
+
+public class DinerMenuIterator implements Iterator {
+    private final MenuItem[] menuItems;
+    private int currentIndex;
+
+    public DinerMenuIterator(MenuItem[] menuItems) {
+        this.menuItems = menuItems;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return currentIndex < menuItems.length && menuItems[currentIndex] != null;
+    }
+
+    @Override
+    public Object next() {
+        if (this.hasNext()) {
+            return menuItems[currentIndex++];
+        }
+        return null;
+    }
+}

Design Patterns/src/iterator/Iterator.java

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+package iterator;
+
+public interface Iterator {
+    boolean hasNext();
+    Object next();
+}
+

Design Patterns/src/iterator/Main.java

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+package iterator;
+
+public class Main {
+    public static void main(String[] args) {
+        Waitress waitress = new Waitress(new PancakeHouseMenu(), new DinerMenu());
+        waitress.printMenu();
+    }
+}

Design Patterns/src/iterator/MenuItem.java

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+package iterator;
+
+public class MenuItem {
+    private final String name;
+    private final String description;
+    private final boolean vegetarian;
+    private final double price;
+
+    public MenuItem(String name, String description, boolean vegetarian, double price) {
+        this.name = name;
+        this.description = description;
+        this.vegetarian = vegetarian;
+        this.price = price;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public boolean isVegetarian() {
+        return vegetarian;
+    }
+
+    public double getPrice() {
+        return price;
+    }
+}

Design Patterns/src/iterator/PancakeHouseMenu.java

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+package iterator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class PancakeHouseMenu {
+    private final List<MenuItem> menuItems = new ArrayList<>();
+
+    public PancakeHouseMenu() {
+
+        addItem("K&B's Pancake Breakfast",
+                "Pancakes with scrambled eggs, and toast",
+                true,
+                2.99);
+
+        addItem("Regular Pancake Breakfast",
+                "Pancakes with fried eggs, sausage",
+                false,
+                2.99);
+
+        addItem("Blueberry Pancakes",
+                "Pancakes made with fresh blueberries",
+                true,
+                3.49);
+
+        addItem("Waffles",
+                "Waffles, with your choice of blueberries or strawberries",
+                true,
+                3.59);
+    }
+
+    public void addItem(String name, String description, boolean vegetarian, double price) {
+        menuItems.add(new MenuItem(name, description, vegetarian, price));
+    }
+
+    public List<MenuItem> getMenuItems() {
+        return menuItems;
+    }
+
+    public Iterator createIterator() {
+        return new PancakeHouseMenuIterator(menuItems);
+    }
+}

Design Patterns/src/iterator/PancakeHouseMenuIterator.java

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+package iterator;
+
+import java.util.List;
+
+public class PancakeHouseMenuIterator implements Iterator {
+    private final List<MenuItem> menuItems;
+    private int currentIndex;
+
+    public PancakeHouseMenuIterator(List<MenuItem> menuItems) {
+        this.menuItems = menuItems;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return currentIndex < menuItems.size();
+    }
+
+    @Override
+    public Object next() {
+        if (this.hasNext()) {
+            return menuItems.get(currentIndex++);
+        }
+        return null;
+    }
+}

Design Patterns/src/iterator/Waitress.java

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+package iterator;
+
+public class Waitress {
+    private final PancakeHouseMenu pancakeHouseMenu;
+    private final DinerMenu dinerMenu;
+
+    public Waitress(PancakeHouseMenu pancakeHouseMenu, DinerMenu dinerMenu) {
+        this.pancakeHouseMenu = pancakeHouseMenu;
+        this.dinerMenu = dinerMenu;
+    }
+
+    public void printMenu() {
+        Iterator pancakeIterator = pancakeHouseMenu.createIterator();
+        Iterator dinerIterator = dinerMenu.createIterator();
+
+        System.out.println("MENU\n----\n\n||--BREAKFAST--||");
+        printMenu(pancakeIterator);
+
+        System.out.println("\n||--LUNCH--||");
+        printMenu(dinerIterator);
+    }
+
+    private void printMenu(Iterator iterator) {
+        while (iterator.hasNext()) {
+            MenuItem menuItem = (MenuItem) iterator.next();
+
+            System.out.println(menuItem.getName() + ", ");
+            System.out.println(menuItem.getPrice() + " -- ");
+            System.out.println(menuItem.getDescription());
+        }
+    }
+}