责任链模式
定义
责任链模式(Chain of Responsibility)使多个对象都有机会处理请求,从而避免请求的发送者和接受者之间的耦合关系。将这些对象连成一条链,并沿着这条链传递该请求,直到有对象能够处理它。
使用场景
链式流程化处理。
例如请假审批流程。
基本思路
创建请求(request 待处理数据)创建多个处理节点(processor),每个节点指定其下一个处理节点。
在起始节点传入请求,最后会通过处理节点条件 判断会有哪些节点处理。
例如:请假审批,[0,1] 天要有Leader1审批
[1,7] 天要有Leader1,Leader2审批
[7,30] 要有Leader1,Leader2,Leader3审批
比如张三请教5天,正常流程需要Leader1,Leader2
张三请教8天,正常流程需要Leader1,Leader2,Leader3
当然这个处理流程可以根据 handlerRequest 的处理条件 来改变。
实现
#ifndef ABSTRACTPROCESSOR_H
#define ABSTRACTPROCESSOR_H
#include <LeaveRequest.h>
class AbstractProcessor{
public:
/**直接主管审批处理的请假天数**/
const static int MIN = 1;
/**部门经理处理的请假天数**/
const static int MIDDLE = 7;
/**总经理处理的请假天数**/
const static int MAX = 30;
/**领导名称*/
std::string handlerName;
/**下一个处理节点(即更高级别的领导)**/
AbstractProcessor* nextHandler = nullptr;
/**设置下一节点**/
void setNextHandler(AbstractProcessor *handler){
this->nextHandler = handler;
}
/**处理请假的请求,子类实现**/
virtual void handlerRequest(LeaveRequest* request) = 0;
};
#endif // ABSTRACTPROCESSOR_H
#ifndef LEADER1PROCESSOR_H
#define LEADER1PROCESSOR_H
#include <AbstractProcessor.h>
#include <stdio.h>
class Leader1Processor:public AbstractProcessor{
public:
void handlerRequest(LeaveRequest* request) override{
if(request->m_iLeaveDays >= AbstractProcessor::MIN){
printf("Leader1:%s,proceess,finished!\n",handlerName.c_str());
if(nullptr != this->nextHandler){
printf("Leader1 ->next \n");
this->nextHandler->handlerRequest(request);
}else{
printf("process reject\n");
}
}else{
printf("not %s duty\n",handlerName.c_str());
return;
}
}
};
#endif // LEADER1PROCESSOR_H
#ifndef LEADER2PROCESSOR_H
#define LEADER2PROCESSOR_H
#include <AbstractProcessor.h>
#include <stdio.h>
class Leader2Processor:public AbstractProcessor{
public:
void handlerRequest(LeaveRequest* request) override{
if(request->m_iLeaveDays >=AbstractProcessor::MIDDLE){
printf("Leader2:%s,proceess,finished!\n",handlerName.c_str());
if(nullptr != this->nextHandler){
printf("Leader2 ->next \n");
this->nextHandler->handlerRequest(request);
}else{
printf("process reject;\n");
}
}else{
printf("not %s duty\n",handlerName.c_str());
return;
}
}
};
#endif // LEADER1PROCESSOR_H
#ifndef LEADER3PROCESSOR_H
#define LEADER3PROCESSOR_H
#include <AbstractProcessor.h>
#include <stdio.h>
class Leader3Processor:public AbstractProcessor{
public:
void handlerRequest(LeaveRequest* request) override{
if(request->m_iLeaveDays<=AbstractProcessor::MAX){
printf("Leader3:%s,proceess,finished!\n",handlerName.c_str());
if(nullptr != this->nextHandler){
printf("Leader3 ->next \n");
this->nextHandler->handlerRequest(request);
}else{
printf("process end;\n");
}
}else{
printf("not %s duty\n",handlerName.c_str());
return;
}
}
};
#endif // LEADER1PROCESSOR_H
#ifndef LEAVEREQUEST_H
#define LEAVEREQUEST_H
#include <string>
class LeaveRequest{
public:
int m_iLeaveDays;
std::string m_strName;
};
#endif // LEAVEREQUEST_H
main
#include <iostream>
using namespace std;
#include <AbstractProcessor.h>
#include <Leader1Processor.h>
#include <Leader2Processor.h>
#include <Leader3Processor.h>
int main()
{
LeaveRequest request;
Leader1Processor processor1;
processor1.handlerName = "Leader1";
Leader2Processor processor2;
processor2.handlerName = "Leader2";
Leader3Processor processor3;
processor3.handlerName = "Leader3";
processor1.setNextHandler(&processor2);
processor2.setNextHandler(&processor3);
request.m_iLeaveDays = 20;
request.m_strName = "Shiver";
printf("%s request Leave for %d\n",request.m_strName.c_str(),request.m_iLeaveDays);
printf("request start\n");
processor1.handlerRequest(&request);
printf("request end\n");
return 0;
}
总结
1、责任链模式使用场景
相对于原数据进行处理比较好,设定总体处理流程。
2、责任链模式与装饰器模式
装饰器模式更像是加上额外功能,每次处理过后原数据都需要转成另一种数据(类)。