/* Handler类
 * 定义一个处理请示的接口
 */
class Handler
{
protected:
	Handler *successor;
	
public:
	virtual ~Handler()
	{
		delete successor;
	}
	void SetSuccessor(Handler *successor)
	{
		this->successor = successor;
	}
	virtual void HandleRequest( int request ) = 0;	// 处理请求的抽象方法
};

/* ConcreteHandler类
 * 具体处理者类，处理它所负责的请求，可访问它的后继者，如果可处理该请求，
 * 就处理之，否则就将该请求转发给它的后继者。
 */

// ConcreteHandler1, 当请求数在0-10之间有权处理，否则转到下一位
class ConcreteHandler1 : public Handler
{
public:
	virtual void HandleRequest( int request )
	{
		if( request >= 0 && request < 10 )
		{
			printf("ConcreteHandler1 处理请求 %d\n", request);
		}
		else if( successor != null )
		{
			successor->HandleRequest( request );
		}
	}
};

class ConcreteHandler2 : public Handler
{
public:
	virtual void HandleRequest( int request )
	{
		if( request >= 10 && request < 20 )
		{
			printf("ConcreteHandler2 处理请求 %d\n", request);
		}
		else if ( successor != null )
		{
			successor->HandleRequest( request );
		}
	}	
};

// 客户端代码
int main()
{
	Handler *h1 = new ConcreteHandler1();
	Handler *h2 = new ConcreteHandler2();
	
	h1->SetSuccessor( h2 );
	
	int req[5] = { 2, 5, 14, 18, 3 };
	
	for( int i = 0; i < 5; ++ i )
	{
		h1->HandleRequest( req[i] );
	}
}