Update state pattern examples

Author: nemanjarogic

src/BehavioralPatterns/State/StateLibrary/ConceptualExample/ConceptualExecutor.cs

@@ -1,8 +1,7 @@
 using BuildingBlocks;
-using StateLibrary.ConceptualExample;
 using StateLibrary.ConceptualExample.States;
 
-namespace ObserverLibrary.StockExample;
+namespace StateLibrary.ConceptualExample;
 
 public static class ConceptualExecutor
 {
@@ -14,4 +13,4 @@ public static void Execute()
         context.Request1();
         context.Request2();
     }
-}
+}

src/BehavioralPatterns/State/StateLibrary/ConceptualExample/Context.cs

@@ -12,10 +12,11 @@ public class Context
     /// <summary>
     /// A reference to the current state of the Context.
     /// </summary>
-    private State _state = null;
+    private State _state;
 
     public Context(State state)
     {
+        _state = state;
         TransitionTo(state);
     }
 
@@ -33,13 +34,7 @@ public void TransitionTo(State state)
     /// <summary>
     /// The Context delegates part of its behavior to the current State object.
     /// </summary>
-    public void Request1()
-    {
-        _state.Handle1();
-    }
+    public void Request1() => _state.Handle1();
 
-    public void Request2()
-    {
-        _state.Handle2();
-    }
-}
+    public void Request2() => _state.Handle2();
+}

src/BehavioralPatterns/State/StateLibrary/ConceptualExample/States/Common/State.cs

@@ -7,14 +7,11 @@
 /// </summary>
 public abstract class State
 {
-    protected Context _context;
+    protected Context? _context;
 
-    public void SetContext(Context context)
-    {
-        _context = context;
-    }
+    public void SetContext(Context context) => _context = context;
 
     public abstract void Handle1();
 
     public abstract void Handle2();
-}
+}

src/BehavioralPatterns/State/StateLibrary/ConceptualExample/States/ConcreteStateA.cs

@@ -9,14 +9,16 @@ public class ConcreteStateA : State
 {
     public override void Handle1()
     {
+        if (_context == null)
+        {
+            return;
+        }
+
         Console.WriteLine("ConcreteStateA handles request1.");
         Console.WriteLine("ConcreteStateA wants to change the state of the context.");
 
         _context.TransitionTo(new ConcreteStateB());
     }
 
-    public override void Handle2()
-    {
-        Console.WriteLine("ConcreteStateA handles request2.");
-    }
-}
+    public override void Handle2() => Console.WriteLine("ConcreteStateA handles request2.");
+}

src/BehavioralPatterns/State/StateLibrary/ConceptualExample/States/ConcreteStateB.cs

@@ -4,16 +4,18 @@ namespace StateLibrary.ConceptualExample.States;
 
 public class ConcreteStateB : State
 {
-    public override void Handle1()
-    {
-        Console.Write("ConcreteStateB handles request1.");
-    }
+    public override void Handle1() => Console.Write("ConcreteStateB handles request1.");
 
     public override void Handle2()
     {
+        if (_context == null)
+        {
+            return;
+        }
+
         Console.WriteLine("ConcreteStateB handles request2.");
         Console.WriteLine("ConcreteStateB wants to change the state of the context.");
 
         _context.TransitionTo(new ConcreteStateA());
     }
-}
+}

src/BehavioralPatterns/State/StateLibrary/Executor.cs

@@ -1,5 +1,5 @@
 using DesignPatternsLibrary.PatternExecutors;
-using ObserverLibrary.StockExample;
+using StateLibrary.ConceptualExample;
 using StateLibrary.PackageExample;
 using StateLibrary.SteakCookingExample;
 
@@ -15,4 +15,4 @@ public override void Execute()
         PackageExecutor.Execute();
         SteakCookingExecutor.Execute();
     }
-}
+}

src/BehavioralPatterns/State/StateLibrary/PackageExample/Package.cs

@@ -7,23 +7,11 @@ public class Package
 {
     private PackageState _state = new OrderedState();
 
-    public void Proceed()
-    {
-        _state.Proceed(this);
-    }
+    public void Proceed() => _state.Proceed(this);
 
-    public void Revert()
-    {
-        _state.Revert(this);
-    }
+    public void Revert() => _state.Revert(this);
 
-    public void PrintStatus()
-    {
-        _state.PrintStatus();
-    }
+    public void PrintStatus() => _state.PrintStatus();
 
-    public void ChangeState(PackageState state)
-    {
-        _state = state;
-    }
-}
+    public void ChangeState(PackageState state) => _state = state;
+}

src/BehavioralPatterns/State/StateLibrary/PackageExample/PackageExecutor.cs

@@ -8,7 +8,7 @@ public static void Execute()
     {
         ConsoleExtension.WriteSeparator("Package example");
 
-        Package package = new Package();
+        var package = new Package();
         package.PrintStatus();
 
         package.Proceed();
@@ -20,4 +20,4 @@ public static void Execute()
         package.Proceed();
         package.PrintStatus();
     }
-}
+}

src/BehavioralPatterns/State/StateLibrary/PackageExample/States/Common/PackageState.cs

@@ -3,8 +3,6 @@
 public abstract class PackageState
 {
     public abstract void Proceed(Package package);
-
     public abstract void Revert(Package package);
-
     public abstract void PrintStatus();
-}
+}

src/BehavioralPatterns/State/StateLibrary/PackageExample/States/DeliveredState.cs

@@ -4,18 +4,12 @@ namespace StateLibrary.PackageExample.States;
 
 public class DeliveredState : PackageState
 {
-    public override void Proceed(Package package)
-    {
+    public override void Proceed(Package package) =>
         package.ChangeState(new ReceivedState());
-    }
 
-    public override void Revert(Package package)
-    {
+    public override void Revert(Package package) =>
         package.ChangeState(new OrderedState());
-    }
 
-    public override void PrintStatus()
-    {
+    public override void PrintStatus() =>
         Console.WriteLine("Package delivered to post office, not received yet.");
-    }
-}
+}