策略模式

• 思想
• C++
• • 策略模式
  • 策略模式与简单工厂模式结合
• GO
• • 策略模式
  • 策略模式与简单工厂模式结合

思想

定义了算法家族，分别封装起来，让他们之间可见相互替换，此模式让算法的变化，不会影响到使用算法的客户
场景—>商场促销

C++

策略模式

/*策略模式*/
#include<iostream>
#include<string>
using namespace std;

class Strategy {
	public:
		virtual void AlgorithmInterface()=0;
};
class ConcreteStrategyA:public Strategy {
	public:
		void AlgorithmInterface() override {
			printf("算法A");
		}
};
class ConcreteStrategyB:public Strategy {
	public:
		void AlgorithmInterface() override {
			printf("算法B");
		}
};
class ConcreteStrategyC:public Strategy {
	public:
		void AlgorithmInterface() override {
			printf("算法C");
		}
};
class Context {
	public:
		Strategy *strategy;
		Context(Strategy *strategy) {
			this->strategy=strategy;
		}
		void ContextInterface() {
			strategy->AlgorithmInterface();
		}
};
//客户端
int main() {
	Context *context=nullptr;

	context=new Context(new ConcreteStrategyA);
	context->ContextInterface();

	context=new Context(new ConcreteStrategyB);
	context->ContextInterface();

	context=new Context(new ConcreteStrategyC);
	context->ContextInterface();
}

策略模式与简单工厂模式结合

/*策略模式与简单工厂模式结合*/
#include<iostream>
#include<string>
using namespace std;

class Strategy {
	public:
		virtual void AlgorithmInterface()=0;
};
class ConcreteStrategyA:public Strategy {
	public:
		void AlgorithmInterface() override {
			printf("算法A");
		}
};
class ConcreteStrategyB:public Strategy {
	public:
		void AlgorithmInterface() override {
			printf("算法B");
		}
};
class ConcreteStrategyC:public Strategy {
	public:
		void AlgorithmInterface() override {
			printf("算法C");
		}
};
class Context {
	public:
		Strategy *strategy;
		Context(char tpye) {
			switch(tpye) {
				case 'A':
					strategy=new ConcreteStrategyA;
					break;
				case 'B':
					strategy=new ConcreteStrategyB;
					break;
				case 'C':
					strategy=new ConcreteStrategyC;
					break;
			}
		}
		void ContextInterface() {
			strategy->AlgorithmInterface();
		}
};
int main() {
	Context *context=nullptr;
	//使得算法与和客户端彻底的隔离
	context=new Context('A');
	context->ContextInterface();
}

GO

策略模式

package main

import "fmt"

type Strategy interface {
	AlgorithmInterface()
}
type ConcreteStrategyA struct {
}
type ConcreteStrategyB struct {
}
type ConcreteStrategyC struct {
}
func (ca *ConcreteStrategyA) AlgorithmInterface() {
	fmt.Println("Algorithm A")
}
func (cb *ConcreteStrategyB) AlgorithmInterface() {
	fmt.Println("Algorithm B")
}
func (cc *ConcreteStrategyC) AlgorithmInterface() {
	fmt.Println("Algorithm C")
}

type Context struct {
	strategy Strategy
}
func (context *Context) ContextInterface() {
	context.strategy.AlgorithmInterface()
}
//客户端
func main(){
	var context Context
	context.strategy=new(ConcreteStrategyA)
	context.ContextInterface()
	context.strategy=new(ConcreteStrategyB)
	context.ContextInterface()
	context.strategy=new(ConcreteStrategyC)
	context.ContextInterface()
}

策略模式与简单工厂模式结合

package main

import "fmt"

type Strategy interface {
	AlgorithmInterface()
}
type ConcreteStrategyA struct {
}
type ConcreteStrategyB struct {
}
type ConcreteStrategyC struct {
}

func (ca *ConcreteStrategyA) AlgorithmInterface() {
	fmt.Println("Algorithm A")
}
func (cb *ConcreteStrategyB) AlgorithmInterface() {
	fmt.Println("Algorithm B")
}
func (cc *ConcreteStrategyC) AlgorithmInterface() {
	fmt.Println("Algorithm C")
}

type Context struct {
	strategy Strategy
}

func (context *Context) ContextInterface() {
	context.strategy.AlgorithmInterface()
}
func (context *Context) init(s string) {
	switch s {
	case "A":
		context.strategy = new(ConcreteStrategyA)
	case "B":
		context.strategy = new(ConcreteStrategyB)
	case "C":
		context.strategy = new(ConcreteStrategyC)
	}
}

//客户端
func main() {
	var context Context
	context.init("A")
	context.ContextInterface()
}