update strategy pattern example

Author: QianMo

Assets/Behavioral Patterns/Strategy Pattern/Example2.meta

@@ -0,0 +1,41 @@
+using UnityEngine;
+using System.Collections;
+
+public class Animal_BadExample
+{
+// bad code:
+public virtual void Fly()
+{
+Debug.Log ("Can Fly");
+}
+}
+
+public class Dog_BadExample : Animal_BadExample
+{
+// bad code:
+public override void Fly()
+{
+// override
+}
+}
+
+public class Cat_BadExample : Animal_BadExample
+{
+// bad code:
+public override void Fly()
+{
+// override
+}
+}
+
+public class Bird_BadExample : Animal_BadExample
+{
+public override void Fly()
+{
+}
+}
+
+// Rembember:
+// ALWAYS
+// eliminate duplicate code
+// eliminate technices that allow one class to affect others

Assets/Behavioral Patterns/Strategy Pattern/Example2/BadCodeExample.cs

@@ -0,0 +1,103 @@
+//-------------------------------------------------------------------------------------
+//	StrategyPatternExample2.cs
+//-------------------------------------------------------------------------------------
+
+using UnityEngine;
+using System.Collections;
+
+namespace StrategyPatternExample2
+{
+ public class StrategyPatternExample2 : MonoBehaviour
+ {
+ void Start()
+ {
+ // create dog and bird example objects
+ Animal sparky = new Dog();
+ Animal tweety = new Bird();
+
+ Debug.Log("Dog: " + sparky.TryToFly());
+ Debug.Log("Bird: " + tweety.TryToFly());
+
+ // change behaviour of dog
+ sparky.SetFlyingAbility(new ItFlys());
+
+ Debug.Log("Dog: " + sparky.TryToFly());
+ Debug.Log("Bird: " + tweety.TryToFly());
+ }
+ }
+
+
+ // Using Interfaces for decoupling
+ // putting behaviour that varies in different classes
+ public interface IFly
+ {
+ string Fly();
+ }
+
+ // Class that holds behaviour for objects that can fly
+ class ItFlys : IFly
+ {
+ public string Fly()
+ {
+ return "Flying high";
+ }
+ }
+
+ // Class that holds behaviour for objects that can not fly
+ class CantFly : IFly
+ {
+ public string Fly()
+ {
+ return "I can't fly";
+ }
+ }
+
+ class FlyingSuperFast : IFly
+ {
+ public string Fly()
+ {
+ return "Fly super fast";
+ }
+ }
+
+
+ // Classes that hold an instance of the behaviours above:
+ public class Animal
+ {
+ // hereby adding the behaviour
+ // it also can change that way
+ public IFly flyingType;
+
+ public string TryToFly()
+ {
+ return flyingType.Fly();
+ }
+
+ public void SetFlyingAbility(IFly newFlyingType)
+ {
+ this.flyingType = newFlyingType;
+ }
+ }
+
+ // derived objects that vary from the base Animal:
+ public class Dog : Animal
+ {
+ public Dog()
+ {
+ flyingType = new CantFly();
+ }
+ }
+
+ public class Bird : Animal
+ {
+ public Bird()
+ {
+ flyingType = new ItFlys();
+ }
+ }
+}
+
+// Rembember:
+// ALWAYS
+// eliminate duplicate code
+// eliminate technices that allow one class to affect others