Added Visitor

Author: NadavMozeson

src/BehavioralPatterns/Visitor/Book.java

@@ -0,0 +1,16 @@
+package BehavioralPatterns.Visitor;
+
+public class Book implements Visitable{
+    private double price;
+    private double weight;
+    public Book(double price, double weight){
+        this.price = price;
+        this.weight = weight;
+    }
+    public void accept(Visitor visitor){
+        visitor.visit(this);
+    }
+    public double getPrice() {return price;}
+    public double getWeight() {return weight;}
+}
+

src/BehavioralPatterns/Visitor/DVD.java

@@ -0,0 +1,15 @@
+package BehavioralPatterns.Visitor;
+
+public class DVD implements Visitable{
+    private double price;
+    private double weight;
+    public DVD(double price, double weight){
+        this.price = price;
+        this.weight = weight;
+    }
+    public void accept(Visitor visitor){
+        visitor.visit(this);
+    }
+    public double getPrice() {return price;}
+    public double getWeight() {return weight;}
+}

src/BehavioralPatterns/Visitor/Main.java

@@ -0,0 +1,11 @@
+package BehavioralPatterns.Visitor;
+
+public class Main {
+    public static void main(String[] args) {
+        ShoppingCart cart = new ShoppingCart();
+        cart.addItem(new Book(20, 5));
+        cart.addItem(new Book(5, 12));
+        cart.addItem(new DVD(50, 5));
+        System.out.println(cart.calculatePostage());
+    }
+}

src/BehavioralPatterns/Visitor/PostageVisitor.java

@@ -0,0 +1,13 @@
+package BehavioralPatterns.Visitor;
+
+public class PostageVisitor implements Visitor {
+    private double totalPostageForCart;
+    public void visit(Book book) {
+        if(book.getPrice() < 10.0)
+            totalPostageForCart += book.getWeight() * 2;
+    }
+    public void visit(DVD dvd) {
+        totalPostageForCart += dvd.getWeight() * 2;
+    }
+    public double getTotalPostage() {return totalPostageForCart;}
+}

src/BehavioralPatterns/Visitor/ShoppingCart.java

@@ -0,0 +1,20 @@
+package BehavioralPatterns.Visitor;
+
+import java.util.ArrayList;
+
+public class ShoppingCart {
+    private ArrayList<Visitable> items = new ArrayList<>();
+
+    public void addItem(Visitable item) {items.add(item);}
+    public void removeItem(Visitable item) {items.remove(item);}
+
+    public double calculatePostage() {
+        PostageVisitor visitor = new PostageVisitor();
+        for(Visitable item: items) {
+            item.accept(visitor);
+        }
+        double postage = visitor.getTotalPostage();
+        return postage;
+    }
+}
+

src/BehavioralPatterns/Visitor/Visitable.java

@@ -0,0 +1,5 @@
+package BehavioralPatterns.Visitor;
+
+public interface Visitable{
+    void accept(Visitor visitor);
+}

src/BehavioralPatterns/Visitor/Visitor.java

@@ -0,0 +1,7 @@
+package BehavioralPatterns.Visitor;
+
+public interface Visitor{
+    void visit(Book book);
+    void visit(DVD dvd);
+}
+