实现一个通用的重试策略类

#include <iostream>
#include <functional>
#include <chrono>
#include <thread>

template <typename ReturnType>
class RetryPolicy {
public:
    enum class DelayStrategy { FIXED, EXPONENTIAL, MULTIPLICATIVE };

    RetryPolicy(int maxRetries, std::function<ReturnType()> func, std::function<bool(ReturnType)> retryCondition, std::function<void()> onMaxRetriesReached, DelayStrategy strategy, int onceWaitTime)
        : maxRetries(maxRetries), func(func), retryCondition(retryCondition), onMaxRetriesReached(onMaxRetriesReached), delayStrategy(strategy), onceWaitTime(onceWaitTime) {}

    void executeWithRetry() {
        int retries = 0;
        while (retries < maxRetries) {
            ReturnType result = func();
            if (retryCondition(result)) {
                return;
            }
            std::this_thread::sleep_for(std::chrono::seconds(getDelay(retries)));
            retries++;
        }
        onMaxRetriesReached();
    }

private:
    int maxRetries;
    int onceWaitTime;
    std::function<ReturnType()> func;
    std::function<bool(ReturnType)> retryCondition;
    std::function<void()> onMaxRetriesReached;
    DelayStrategy delayStrategy;

    int getDelay(int attempt) {
        switch (delayStrategy) {
            case DelayStrategy::FIXED:
                return onceWaitTime; // 固定时长策略
            case DelayStrategy::EXPONENTIAL:
                return onceWaitTime * (1 << attempt); // 指数增长策略
            case DelayStrategy::MULTIPLICATIVE:
                return onceWaitTime * (attempt + 1); // 固定倍数增长策略
            default:
                return 0;
        }
    }
};

int performOperation() {
    // 模拟执行的操作
    static int attempts = 0;
    std::cout << "Performing operation... Attempt " << attempts + 1 << std::endl;
    attempts++;
    if (attempts < 3) {
        std::cout << "Operation failed." << std::endl;
        return 0;  // 模拟失败情况
    } else {
        std::cout << "Operation succeeded." << std::endl;
        return 1;  // 模拟成功情况
    }
}

int main() {
    // 定义重试策略
    RetryPolicy<int> retry(5, performOperation, [](int result) { return result != 0; }, []{ std::cout << "Max retries reached." << std::endl; }, RetryPolicy<int>::DelayStrategy::EXPONENTIAL);

    // 执行操作的重试
    retry.executeWithRetry();

    return 0;
}

运行结果