C++로 작성된 퍼사드

퍼사드는 구조 디자인 패턴이며 간단한 (그러나 제한된 인터페이스를 클래스, 라이브러리 또는 프레임워크로 구성된 복잡한 시스템에 제공합니다.

퍼사드는 앱의 전반적인 복잡성을 줄이는 동시에 원치 않는 의존성들을 한 곳으로 옮기는 것을 돕습니다.

퍼사드에 대하여 더 자세히 알아보세요

복잡도:

인기도:

사용 사례들: 퍼사드 패턴은 일반적으로 C++ 코드로 작성된 앱에서 사용되며 또 복잡한 라이브러리 및 API와 작업할 때 특히 편리합니다.

식별: 퍼사드는 인터페이스가 간단하나 대부분의 작업을 다른 클래스들에 위임하는 클래스의 존재여부로 식별할 수 있으며 일반적으로 퍼사드들은 사용하는 객체들의 전체 수명 주기를 관리합니다.

개념적인 예시

이 예시는 퍼사드 패턴의 구조를 보여주고 다음 질문에 중점을 둡니다:

패턴은 어떤 클래스들로 구성되어 있나요?
이 클래스들은 어떤 역할을 하나요?
패턴의 요소들은 어떻게 서로 연관되어 있나요?

main.cc: 개념적인 예시

/**
 * The Subsystem can accept requests either from the facade or client directly.
 * In any case, to the Subsystem, the Facade is yet another client, and it's not
 * a part of the Subsystem.
 */
class Subsystem1 {
 public:
  std::string Operation1() const {
    return "Subsystem1: Ready!\n";
  }
  // ...
  std::string OperationN() const {
    return "Subsystem1: Go!\n";
  }
};
/**
 * Some facades can work with multiple subsystems at the same time.
 */
class Subsystem2 {
 public:
  std::string Operation1() const {
    return "Subsystem2: Get ready!\n";
  }
  // ...
  std::string OperationZ() const {
    return "Subsystem2: Fire!\n";
  }
};

/**
 * The Facade class provides a simple interface to the complex logic of one or
 * several subsystems. The Facade delegates the client requests to the
 * appropriate objects within the subsystem. The Facade is also responsible for
 * managing their lifecycle. All of this shields the client from the undesired
 * complexity of the subsystem.
 */
class Facade {
 protected:
  Subsystem1 *subsystem1_;
  Subsystem2 *subsystem2_;
  /**
   * Depending on your application's needs, you can provide the Facade with
   * existing subsystem objects or force the Facade to create them on its own.
   */
 public:
  /**
   * In this case we will delegate the memory ownership to Facade Class
   */
  Facade(
      Subsystem1 *subsystem1 = nullptr,
      Subsystem2 *subsystem2 = nullptr) {
    this->subsystem1_ = subsystem1 ?: new Subsystem1;
    this->subsystem2_ = subsystem2 ?: new Subsystem2;
  }
  ~Facade() {
    delete subsystem1_;
    delete subsystem2_;
  }
  /**
   * The Facade's methods are convenient shortcuts to the sophisticated
   * functionality of the subsystems. However, clients get only to a fraction of
   * a subsystem's capabilities.
   */
  std::string Operation() {
    std::string result = "Facade initializes subsystems:\n";
    result += this->subsystem1_->Operation1();
    result += this->subsystem2_->Operation1();
    result += "Facade orders subsystems to perform the action:\n";
    result += this->subsystem1_->OperationN();
    result += this->subsystem2_->OperationZ();
    return result;
  }
};

/**
 * The client code works with complex subsystems through a simple interface
 * provided by the Facade. When a facade manages the lifecycle of the subsystem,
 * the client might not even know about the existence of the subsystem. This
 * approach lets you keep the complexity under control.
 */
void ClientCode(Facade *facade) {
  // ...
  std::cout << facade->Operation();
  // ...
}
/**
 * The client code may have some of the subsystem's objects already created. In
 * this case, it might be worthwhile to initialize the Facade with these objects
 * instead of letting the Facade create new instances.
 */

int main() {
  Subsystem1 *subsystem1 = new Subsystem1;
  Subsystem2 *subsystem2 = new Subsystem2;
  Facade *facade = new Facade(subsystem1, subsystem2);
  ClientCode(facade);

  delete facade;

  return 0;
}

Output.txt: 실행 결과

Facade initializes subsystems:
Subsystem1: Ready!
Subsystem2: Get ready!
Facade orders subsystems to perform the action:
Subsystem1: Go!
Subsystem2: Fire!