Protection Proxy
/*:
### Example
*/
protocol DoorOperator {
func open(doors: String) -> String
}
class HAL9000 : DoorOperator {
func open(doors: String) -> String {
return ("HAL9000: Affirmative, Dave. I read you. Opened \(doors).")
}
}
class CurrentComputer : DoorOperator {
private var computer: HAL9000!
func authenticate(password: String) -> Bool {
guard password == "pass" else {
return false;
}
computer = HAL9000()
return true
}
func open(doors: String) -> String {
guard computer != nil else {
return "Access Denied. I'm afraid I can't do that."
}
return computer.open(doors: doors)
}
}
/*:
### Usage
*/
let computer = CurrentComputer()
let podBay = "Pod Bay Doors"
computer.open(doors: podBay)
computer.authenticate(password: "pass")
computer.open(doors: podBay)
Virtual Proxy
/*:
### Example
*/
protocol HEVSuitMedicalAid {
func administerMorphine() -> String
}
class HEVSuit : HEVSuitMedicalAid {
func administerMorphine() -> String {
return "Morphine administered."
}
}
class HEVSuitHumanInterface : HEVSuitMedicalAid {
lazy private var physicalSuit: HEVSuit = HEVSuit()
func administerMorphine() -> String {
return physicalSuit.administerMorphine()
}
}
/*:
### Usage
*/
let humanInterface = HEVSuitHumanInterface()
humanInterface.administerMorphine()
