Міст на C++

/** * The Implementation defines the interface for all implementation classes. It * doesn't have to match the Abstraction's interface. In fact, the two * interfaces can be entirely different. Typically the Implementation interface * provides only primitive operations, while the Abstraction defines higher- * level operations based on those primitives. */ class Implementation { public: virtual ~Implementation() {} virtual std::string OperationImplementation() const = 0; }; /** * Each Concrete Implementation corresponds to a specific platform and * implements the Implementation interface using that platform's API. */ class ConcreteImplementationA : public Implementation { public: std::string OperationImplementation() const override { return "ConcreteImplementationA: Here's the result on the platform A.\n"; } }; class ConcreteImplementationB : public Implementation { public: std::string OperationImplementation() const override { return "ConcreteImplementationB: Here's the result on the platform B.\n"; } }; /** * The Abstraction defines the interface for the "control" part of the two class * hierarchies. It maintains a reference to an object of the Implementation * hierarchy and delegates all of the real work to this object. */ class Abstraction { /** * @var Implementation */ protected: Implementation* implementation_; public: Abstraction(Implementation* implementation) : implementation_(implementation) { } virtual ~Abstraction() { } virtual std::string Operation() const { return "Abstraction: Base operation with:\n" + this->implementation_->OperationImplementation(); } }; /** * You can extend the Abstraction without changing the Implementation classes. */ class ExtendedAbstraction : public Abstraction { public: ExtendedAbstraction(Implementation* implementation) : Abstraction(implementation) { } std::string Operation() const override { return "ExtendedAbstraction: Extended operation with:\n" + this->implementation_->OperationImplementation(); } }; /** * Except for the initialization phase, where an Abstraction object gets linked * with a specific Implementation object, the client code should only depend on * the Abstraction class. This way the client code can support any abstraction- * implementation combination. */ void ClientCode(const Abstraction& abstraction) { // ... std::cout << abstraction.Operation(); // ... } /** * The client code should be able to work with any pre-configured abstraction- * implementation combination. */ int main() { Implementation* implementation = new ConcreteImplementationA; Abstraction* abstraction = new Abstraction(implementation); ClientCode(*abstraction); std::cout << std::endl; delete implementation; delete abstraction; implementation = new ConcreteImplementationB; abstraction = new ExtendedAbstraction(implementation); ClientCode(*abstraction); delete implementation; delete abstraction; return 0; } 

Abstraction: Base operation with: ConcreteImplementationA: Here's the result on the platform A. ExtendedAbstraction: Extended operation with: ConcreteImplementationB: Here's the result on the platform B.