*/
  @GuardedBy("lock")
  private int runningTasks = 0;

  @GuardedBy("lock")
  private boolean shutdown = false;

  @Override
  public void execute(Runnable command) {
    startTask();
    try {
      command.run();
    } finally {
      endTask();
    }
  }

  @Override
  public boolean isShutdown() {
    synchronized (lock) {
      return shutdown;
    }
  }

	}
}

// Lock holds a write lock on dm.
//
// If the lock is already in use, the calling go routine
// blocks until the mutex is available.
func (dm *DRWMutex) Lock(id, source string) {
	isReadLock := false
	dm.lockBlocking(context.Background(), nil, id, source, isReadLock, Options{
		Timeout: drwMutexInfinite,
	})
}

// Options lock options.
type Options struct {

type NetLocker interface {
	// Do read lock for given LockArgs.  It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.
	RLock(ctx context.Context, args LockArgs) (bool, error)

	// Do write lock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.

    final Lock lock;

    LockingThread(Lock lock) {
      this.lock = lock;
    }

    @Override
    public void run() {
      lock.lock();
      try {
        locked.countDown();
        finishLatch.await(1, MINUTES);
      } catch (InterruptedException e) {
        fail(e.toString());
      } finally {
        lock.unlock();
      }
    }

	Source          string // Contains line, function and filename requesting the lock.
	Group           bool   // indicates if it was a group lock.
	Owner           string // Owner represents the UUID of the owner who originally requested the lock.
	Quorum          int    // Quorum represents the quorum required for this lock to be active.
	idx             int    `msg:"-"` // index of the lock in the lockMap.
}

        }
      };

  private static final Supplier<Lock> LOCK_SUPPLER =
      new Supplier<Lock>() {
        @Override
        public Lock get() {
          return new ReentrantLock();
        }
      };

  private static final Supplier<Lock> FAIR_LOCK_SUPPLER =
      new Supplier<Lock>() {
        @Override
        public Lock get() {
          return new ReentrantLock(true);
        }
      };

        }
      };

  private static final Supplier<Lock> LOCK_SUPPLER =
      new Supplier<Lock>() {
        @Override
        public Lock get() {
          return new ReentrantLock();
        }
      };

  private static final Supplier<Lock> FAIR_LOCK_SUPPLER =
      new Supplier<Lock>() {
        @Override
        public Lock get() {
          return new ReentrantLock(true);
        }
      };

  enum Impl {
    EAGER {
      @Override
      Striped<Lock> get(int stripes) {
        return Striped.lock(stripes);
      }
    },
    LAZY_SMALL {
      @Override
      Striped<Lock> get(int stripes) {
        return new Striped.SmallLazyStriped<>(stripes, LOCK_SUPPLIER);
      }
    },
    LAZY_LARGE {
      @Override
      Striped<Lock> get(int stripes) {

  enum Impl {
    EAGER {
      @Override
      Striped<Lock> get(int stripes) {
        return Striped.lock(stripes);
      }
    },
    LAZY_SMALL {
      @Override
      Striped<Lock> get(int stripes) {
        return new Striped.SmallLazyStriped<>(stripes, LOCK_SUPPLIER);
      }
    },
    LAZY_LARGE {
      @Override
      Striped<Lock> get(int stripes) {

     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;
        this.currentFuture = currentFuture;
      }