结构型模式之适配器模式

设计模式 

创建模式之单例模式

问题：

假如你正在开发一款股票市场监测程序(client)， 它会从不同来源下载 XML 格式的股票数据， 然后向用户呈现出美观的图表。

在开发过程中， 你决定在程序中整合一个第三方智能分析函数库(server)。 但是遇到了一个问题， 那就是分析函数库只兼容 JSON 格式的数据。

你可以创建一个适配器。 这是一个特殊的对象， 能够转换对象接口， 使其能与其他对象进行交互。

 

 main.cc: 概念示例   ：同时继承client和server，

/**
 * The Target defines the domain-specific interface used by the client code.
 */
class Target {
 public:
  virtual ~Target() = default;
  virtual std::string Request() const {
    return "Target: The default target's behavior.";
  }
};

/**
 * The Adaptee contains some useful behavior, but its interface is incompatible
 * with the existing client code. The Adaptee needs some adaptation before the
 * client code can use it.
 */
class Adaptee {
 public:
  std::string SpecificRequest() const {
    return ".eetpadA eht fo roivaheb laicepS";
  }
};

/**
 * The Adapter makes the Adaptee's interface compatible with the Target's
 * interface using multiple inheritance.
 */
class Adapter : public Target, public Adaptee {
 public:
  Adapter() {}
  std::string Request() const override {
    std::string to_reverse = SpecificRequest();
    std::reverse(to_reverse.begin(), to_reverse.end());
    return "Adapter: (TRANSLATED) " + to_reverse;
  }
};

/**
 * The client code supports all classes that follow the Target interface.
 */
void ClientCode(const Target *target) {
  std::cout << target->Request();
}

int main() {
  std::cout << "Client: I can work just fine with the Target objects:\n";
  Target *target = new Target;
  ClientCode(target);
  std::cout << "\n\n";
  Adaptee *adaptee = new Adaptee;
  std::cout << "Client: The Adaptee class has a weird interface. See, I don't understand it:\n";
  std::cout << "Adaptee: " << adaptee->SpecificRequest();
  std::cout << "\n\n";
  std::cout << "Client: But I can work with it via the Adapter:\n";
  Adapter *adapter = new Adapter;
  ClientCode(adapter);
  std::cout << "\n";

  delete target;
  delete adaptee;
  delete adapter;

  return 0;
}

Output.txt: 执行结果

Client: I can work just fine with the Target objects:
Target: The default target's behavior.

Client: The Adaptee class has a weird interface. See, I don't understand it:
Adaptee: .eetpadA eht fo roivaheb laicepS

Client: But I can work with it via the Adapter:
Adapter: (TRANSLATED) Special behavior of the Adaptee.