Java中的优先级ThreadPoolExecutor(Android)

Question

我正在尝试优先创建一个ThreadPoolExecutor.所以我定义了一个

private static ThreadPoolExecutor threadpool = new ThreadPoolExecutor(30, MAXPOOL,  MAXPOOL, TimeUnit.SECONDS,  
     queue, new mThreadFactory());

所以关键是现在的队列引用.但是当我宣布:

static PriorityBlockingQueue<mDownloadThread> queue=new PriorityBlockingQueue<mDownloadThread>(MAXPOOL,new DownloadThreadComparator());

编译器在第一行中给出错误:构造函数ThreadPoolExecutor(int,int,int,TimeUnit,PriorityBlockingQueue,FileAccess.mThreadFactory)未使用单个quickfix进行定义:将"queue"类型更改为BlockingQueue.你能帮我理解这个问题吗？

谢谢

附加信息:

为了比较runnables,我实现了以下类

class mDownloadThread implements Runnable{      
    private Runnable mRunnable;     
    private int priority;       
    mDownloadThread(Runnable runnable){
        mRunnable=runnable;         
    }

    @Override
    public void run() {
        mRunnable.run();        
    }

    public int getPriority() {
        return priority;
    }

    public void setPriority(int priority) {
        this.priority = priority;
    }       
}

比较器:

class DownloadThreadComparator implements Comparator<mDownloadThread>{
    @Override
    public int compare(mDownloadThread arg0, mDownloadThread arg1) {

    if (arg0==null && arg1==null){
        return 0;
    } else if (arg0==null){
        return -1;
    } else if (arg1==null){
        return 1;
    }
    return arg0.getPriority()-arg1.getPriority();

    }

}

Answer 1

ThreadPoolExecutor构造函数接受BlockingQueue<Runnable>而不是BlockingQueue<? extends Runnable>,因此您无法传递给它PriorityBlockingQueue<mDownloadThread>实例.

您可以更改类型queue到PriorityBlockingQueue<Runnable>,但在这种情况下,你将无法实现Comparator<mDownloadThread>无内铸造compare方法.

另一种解决方案是绕过泛型类型检查,但是您只需要提交mDownloadThreadto execute方法的实例:

static ThreadPoolExecutor threadpool = new ThreadPoolExecutor(30, MAXPOOL, 
        MAXPOOL, TimeUnit.SECONDS, (PriorityBlockingQueue) queue, new mThreadFactory());