Adding code for Animals in Chapter 1

src/headfirst/designpatterns/strategy/AnimalTest.java

@@ -0,0 +1,40 @@
+package headfirst.designpatterns.strategy;
+
+import java.util.ArrayList;
+
+public class AnimalTest {
+
+	public static void main(String[] args) {
+		AnimalTest at = new AnimalTest();
+		at.makeSomeAnimals();
+	}
+	public void makeSomeAnimals() {
+		Animal dog = new Dog();
+		Animal cat = new Cat();
+		// treat dogs and cats as their supertype, Animal
+		ArrayList<Animal> animals = new ArrayList<Animal>();
+		animals.add(dog);
+		animals.add(cat);
+		animals.forEach(Animal::makeSound); // can call makeSound on any Animal
+	}
+
+	public abstract class Animal {
+		abstract void makeSound();
+	}
+	public class Dog extends Animal {
+		void makeSound() {
+			bark();
+		}
+		void bark() {
+			System.out.println("Woof");
+		}
+	}
+	public class Cat extends Animal {
+		void makeSound() {
+			meow();
+		}
+		void meow() {
+			System.out.println("Meow");
+		}
+	}
+}