dubbo线程池的拒绝策略

jdk自带的原生的拒绝策略抛出的异常信息不够详细，无法反映业务处理相关的信息，而dubbo对拒绝策略进行了改写，抛出的信息更具有参考价值，值得我们借鉴。

jdk自带的原生拒绝策略抛出的信息：

// ThreadPoolExecutor的toString方法
/**
* Returns a string identifying this pool, as well as its state,
* including indications of run state and estimated worker and
* task counts.
*
* @return a string identifying this pool, as well as its state
*/
public String toString() {
    long ncompleted;
    int nworkers, nactive;
    final ReentrantLock mainLock = this.mainLock;
    mainLock.lock();
    try {
        ncompleted = completedTaskCount;
        nactive = 0;
        nworkers = workers.size();
        for (Worker w : workers) {
            ncompleted += w.completedTasks;
            if (w.isLocked())
                ++nactive;
        }
    } finally {
        mainLock.unlock();
    }
    int c = ctl.get();
    String rs = (runStateLessThan(c, SHUTDOWN) ? "Running" :
                    (runStateAtLeast(c, TERMINATED) ? "Terminated" :
                    "Shutting down"));
    return super.toString() +
        "[" + rs +
        ", pool size = " + nworkers +
        ", active threads = " + nactive +
        ", queued tasks = " + workQueue.size() +
        ", completed tasks = " + ncompleted +
        "]";
}

dubbo的线程池的拒绝策略抛出的信息：

// com.alibaba.dubbo.common.threadpool.support.AbortPolicyWithReport
@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
    String msg = String.format("Thread pool is EXHAUSTED!" +
            " Thread Name: %s, Pool Size: %d (active: %d, core: %d, max: %d, largest: %d), Task: %d (completed: %d)," +
            " Executor status:(isShutdown:%s, isTerminated:%s, isTerminating:%s), in %s://%s:%d!" ,
            threadName, e.getPoolSize(), e.getActiveCount(), e.getCorePoolSize(), e.getMaximumPoolSize(), e.getLargestPoolSize(),
            e.getTaskCount(), e.getCompletedTaskCount(), e.isShutdown(), e.isTerminated(), e.isTerminating(),
            url.getProtocol(), url.getIp(), url.getPort());
    logger.warn(msg);
    throw new RejectedExecutionException(msg);
}