protection proxy and virtual proxy

Author: Sebastian Boldt

GOFSwift.xcworkspace/xcuserdata/sboldt.xcuserdatad/UserInterfaceState.xcuserstate

@@ -13,8 +13,8 @@
 * ✅ Strategy
 * ✅ Mediator
 * ✅ Visitor
-* ❌ Interpreter
 * ❌ Memento
+* ❌ Interpreter
 * ❌ Observer
 * ❌ State
 
@@ -35,5 +35,5 @@
 * ✅ Adapter
 * ✅ Flyweight
 * ✅ Facade
-* ❌ Protection Proxy
-* ❌ Virtual Proxy
+* ✅ Protection Proxy
+* ✅ Virtual Proxy

README.md

@@ -0,0 +1,39 @@
+//: [Previous](@previous)
+
+import Foundation
+
+enum AuthError: Error {
+    case unauthorized
+}
+
+class PasswordStore {
+    func showSecretInformation() -> String {
+        return "SecretPassword"
+    }
+}
+
+class PasswordTresor {
+    var resourceToProtect: PasswordStore?
+    func authenticate(password: String) -> Bool {
+        guard password == "password" else {
+            return false
+        }
+        resourceToProtect = PasswordStore()
+        return true
+    }
+    
+    func showSecretInformation() throws -> String {
+        guard let resourceToProtect = resourceToProtect else {
+            throw AuthError.unauthorized
+        }
+        return resourceToProtect.showSecretInformation()
+    }
+}
+
+//Usage
+
+let tresor = PasswordTresor()
+tresor.authenticate(password: "password")
+try tresor.showSecretInformation()
+
+//: [Next](@next)

Structural.playground/Pages/Protection Proxy.xcplaygroundpage/Contents.swift

@@ -0,0 +1,26 @@
+//: [Previous](@previous)
+
+import Foundation
+
+protocol Server {
+    func compute() -> String
+}
+
+struct ExpensiveServer: Server {
+    func compute() -> String {
+        return "Computation completed"
+    }
+}
+
+class ExpensiveServerInterface: Server {
+    lazy private var expensiveServer = ExpensiveServer()
+    
+    func compute() -> String {
+        return expensiveServer.compute()
+    }
+}
+
+let serverInterface = ExpensiveServerInterface()
+serverInterface.compute()
+
+//: [Next](@next)

Structural.playground/Pages/Virtual Proxy.xcplaygroundpage/Contents.swift

@@ -7,5 +7,7 @@
         <page name='Adapter'/>
         <page name='Flyweight'/>
         <page name='Facade'/>
+        <page name='Protection Proxy'/>
+        <page name='Virtual Proxy'/>
     </pages>
 </playground>