java - 枚举的 HashMap 作为键

Question

我之前也发过类似的问题。我的疑惑也得到了澄清。但我仍然需要更多东西。 Hashmap 将使用枚举对象作为键和线程池实例作为值进行初始化。我很困惑如何为其他进程调用的每个对象初始化 HashMap ..要明确:我的程序，MyThreadpoolExcecutorPgm.java 初始化一个HashMap我的 Progran AdditionHandler.java 通过传递 ThreadpoolName(枚举)从 HashMap 请求一个线程。我收到“HashMap 没有可用的线程”消息。请帮帮我。
下面给出的是我的代码:

 public class MyThreadpoolExcecutorPgm {

    enum ThreadpoolName {
        DR, BR, SV, MISCELLENEOUS;
    }

    private static String threadName;
    private static HashMap<ThreadpoolName, ThreadPoolExecutor>
        threadpoolExecutorHash;

    public MyThreadpoolExcecutorPgm(String p_threadName) {
        threadName = p_threadName;
    }

    public static void fillthreadpoolExecutorHash() {
        int poolsize = 3;
        int maxpoolsize = 3;
        long keepAliveTime = 10;
        ThreadPoolExecutor tp = null;
        threadpoolExecutorHash = new HashMap<ThreadpoolName, ThreadPoolExecutor>();
        for (ThreadpoolName poolName : ThreadpoolName.) // failing to implement
        {
            tp = new ThreadPoolExecutor(poolsize, maxpoolsize, keepAliveTime,
                    TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(5));
            threadpoolExecutorHash.put(poolName, tp);
        }
    }

    public static ThreadPoolExecutor getThreadpoolExcecutor(
            ThreadpoolName poolName) {
        ThreadPoolExecutor thread = null;
        if (threadpoolExecutorHash != null && poolName != null) {
            thread = threadpoolExecutorHash.get(poolName);
        } else {
            System.out.println("No thread available from HashMap");
        }
        return thread;
    }
}

AdditionHandler.java

public class AdditionHandler{

    public void handle() {
        AddProcess setObj = new AddProcess(5, 20);
        ThreadPoolExecutor tpe = null;
        ThreadpoolName poolName =ThreadpoolName.DR; //i am using my enum    
        tpe = MyThreadpoolExcecutorPgm.getThreadpoolExcecutor(poolName);
        tpe.execute(setObj);
    }

    public static void main(String[] args) {
        AdditionHandler obj = new AdditionHandler();
        obj.handle();
    }
}

Answer 1

我怀疑您只是在寻找添加到每个枚举中的静态 values() 方法:

for (ThreadpoolName poolName : ThreadpoolName.getValues())

或者，您可以使用 EnumSet.allOf():

for (ThreadpoolName poolName : EnumSet.allOf(ThreadpoolName.class))

(正如 Bozho 所说，EnumMap 是一个不错的选择。您仍然需要遍历枚举值。)