factory method2.cpp

来自「C++课件,很好用的,帮助大家学习C++.」· C++ 代码 · 共 32 行

//去掉了ShapeFactory的两个子类,改为由ShapeFactory直接负责实例的创建.
// ShapeFactory自己变成一个具体的创建器,直接用参数化的方法实现factoryMethod返回多种对象. 
class ShapeFactory {  
private: static Shape s;
		 ShapeFactory() {}
		 
		 static Shape factoryMethod(String aName, String aType) {
			 if (aType.compareTo("square")==0)
				 return new Square(aName);
			 else if (aType.compareTo("circle")==0)
				 return new Circle(aName);
			 else throw new NoThisShape(aType);  
		 }
		 
		 // 在anOperation中定义Shape的一系列行为
		 static void anOperation(String aName, String aType) throws NoThisShape{
			 s = factoryMethod(aName, aType);
			 cout<<"The current shape is: " + s.name<<endl;
			 s.draw();
			 s.erase();
		 }
};
void main(){
	ShapeFactory::anOperation("Shape one","circle");
	ShapeFactory::anOperation("Shape two","square");
	ShapeFactory::anOperation("Shape three", "delta");
  }
}