design patterns : composite

design-pattern/gof/src/composite/after/Bag.java

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+package composite.after;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Bag implements Component {
+
+    private List<Component> components = new ArrayList<>();
+
+    public void add(Component component) {
+        components.add(component);
+    }
+
+    public List<Component> getComponents() {
+        return components;
+    }
+
+    @Override
+    public int getPrice() {
+        return components.stream().mapToInt(Component::getPrice).sum();
+    }
+}

design-pattern/gof/src/composite/after/Client.java

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+package composite.after;
+
+public class Client {
+
+    public static void main(String[] args) {
+        Item doranBlade = new Item("도란검", 450);
+        Item healPotion = new Item("체력 물약", 50);
+
+        Bag bag = new Bag();
+        bag.add(doranBlade);
+        bag.add(healPotion);
+
+        Client client = new Client();
+        client.printPrice(doranBlade);
+        client.printPrice(bag);
+    }
+
+    private void printPrice(Component component)  {
+        System.out.println(component.getPrice());
+    }
+
+}

design-pattern/gof/src/composite/after/Component.java

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+package composite.after;
+
+public interface Component {
+    int getPrice();
+}

design-pattern/gof/src/composite/after/Item.java

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+package composite.after;
+
+public class Item implements Component {
+
+    private String name;
+
+    private int price;
+
+    public Item(String name, int price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    @Override
+    public int getPrice() {
+        return this.price;
+    }
+}

design-pattern/gof/src/composite/before/Bag.java

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+package composite.before;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Bag {
+
+    private List<Item> items = new ArrayList<>();
+
+    public void add(Item item) {
+        items.add(item);
+    }
+
+    public List<Item> getItems() {
+        return items;
+    }
+}

design-pattern/gof/src/composite/before/Client.java

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+package composite.before;
+
+import java.util.stream.Collectors;
+
+public class Client {
+
+    public static void main(String[] args) {
+        Item doranBlade = new Item("도란검", 450);
+        Item healPotion = new Item("체력 물약", 50);
+
+        Bag bag = new Bag();
+        bag.add(doranBlade);
+        bag.add(healPotion);
+
+        Client client = new Client();
+        client.printPrice(doranBlade);
+        client.printPrice(bag);
+    }
+
+    private void printPrice(Item item)  {
+        System.out.println(item.getPrice());
+    }
+
+    private void printPrice(Bag bag) {
+        int sum = bag.getItems().stream().mapToInt(Item::getPrice).sum();
+        System.out.println(sum);
+    }
+
+}

design-pattern/gof/src/composite/before/Item.java

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+package composite.before;
+
+public class Item {
+
+    private String name;
+
+    private int price;
+
+    public Item(String name, int price) {
+        this.name = name;
+        this.price = price;
+    }
+
+    public int getPrice() {
+        return this.price;
+    }
+}