08-中介者模式-C语言实现

中介者模式： Define an object that encapsulates how a set of objects interact.Mediator promotes loose coupling by keeping objects from referring to each other explicitly,and it lets you vary their interaction independently.（用一个中介对象封装一系列的对象交互，中介者使各对象不需要显示地相互作用，从而使其耦合松散，而且可以独立地改变它们之间的交互。）

UML图：

代码实现：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// 中介者接口
typedef struct {
    void (*notify)(void*, char*);
} Mediator;

// 具体中介者类
typedef struct {
    Mediator mediator;
    char* name;
} ConcreteMediator;

void ConcreteMediator_notify(void* obj, char* message) {
    ConcreteMediator* self = (ConcreteMediator*)obj;
    printf("%s received message: %s\n", self->name, message);
}

ConcreteMediator createConcreteMediator(char* name) {
    ConcreteMediator mediator;
    mediator.mediator.notify = ConcreteMediator_notify;
    mediator.name = malloc(strlen(name) + 1);
    strcpy(mediator.name, name);
    return mediator;
}

// 抽象同事类
typedef struct {
    void (*send)(void*, char*);
    void (*receive)(void*, char*);
} Colleague;

// 具体同事类
typedef struct {
    Colleague colleague;
    Mediator* mediator;
    char* name;
} ConcreteColleague;

void ConcreteColleague_send(void* obj, char* message) {
    ConcreteColleague* self = (ConcreteColleague*)obj;
    printf("%s sends message: %s\n", self->name, message);
    self->mediator->notify(self->mediator, message);
}

void ConcreteColleague_receive(void* obj, char* message) {
    ConcreteColleague* self = (ConcreteColleague*)obj;
    printf("%s received message: %s\n", self->name, message);
}

ConcreteColleague createConcreteColleague(char* name, Mediator* mediator) {
    ConcreteColleague colleague;
    colleague.colleague.send = ConcreteColleague_send;
    colleague.colleague.receive = ConcreteColleague_receive;
    colleague.mediator = mediator;
    colleague.name = malloc(strlen(name) + 1);
    strcpy(colleague.name, name);
    return colleague;
}

int main() {
    ConcreteMediator mediator = createConcreteMediator("Mediator");
    ConcreteColleague colleague1 = createConcreteColleague("Colleague1", &mediator.mediator);
    ConcreteColleague colleague2 = createConcreteColleague("Colleague2", &mediator.mediator);

    colleague1.colleague.send(&colleague1, "Hello, Colleague2!");
    colleague2.colleague.send(&colleague2, "Hi, Colleague1!");

    free(mediator.name);
    free(colleague1.name);
    free(colleague2.name);

    return 0;
}

在上面的示例代码中，定义了中介者接口Mediator和具体中介者类ConcreteMediator，实现了通知方法来处理同事对象之间的交互。

同时还定义了抽象同事类Colleague和具体同事类ConcreteColleague，实现了发送和接收方法，并通过中介者对象来处理同事之间的交互。

在main函数中，首先创建了一个具体中介者对象mediator，然后创建了两个具体同事对象colleague1和colleague2，并将中介者对象传入。

然后通过调用同事对象的发送方法来向另一个同事对象发送消息，中介者对象将处理这些消息，最后输出了结果。