default:
		err = errors.New(r.Err)
	}
	return ok, err
}

// RLock calls read lock REST API.
func (c *lockRESTClient) RLock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCRLock, &args)
}

// Lock calls lock REST API.
func (c *lockRESTClient) Lock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCLock, &args)
}

// ensure that Unlock is always called when Lock succeeds.
func Lock(f File) error {
	return lock(f, writeLock)
}

// RLock places an advisory read lock on the file, blocking until it can be locked.
//
// If RLock returns nil, no other process will be able to place a write lock on
// the file until this process exits, closes f, or calls Unlock on it.
//

    }

    @SuppressWarnings("try")
    private <T> T withBuildLogicQueueLock(Supplier<T> buildAction) {
        lock.lock();
        try {
            final boolean firstLockHolder = lock.getHoldCount() == 1;
            if (firstLockHolder) { // lock file at the top of the callstack only
                try (FileLock ignored = lockBuildLogicQueueFile()) {
                    return buildAction.get();

    private final List<EndPointQueue> waiting = new ArrayList<EndPointQueue>();
    private final Lock lock;
    private final QueueInitializer initializer = new QueueInitializer();

    public MultiEndPointQueue(Lock lock) {
        this.lock = lock;
    }

    @Override
    public void dispatch(InterHubMessage message) {
        queue.add(message);
        flush();
    }

        lock.lock();
        try {
            items.get(operation).removeAll(workItems);
            waiting.add(operation);
        } finally {
            lock.unlock();
        }
    }

    private void stopWaiting(BuildOperationRef operation) {
        lock.lock();
        try {
            waiting.remove(operation);
        } finally {

		//    successfully acquiring the lock.
		// 2) lk2 then needs to advance and remove the resource from lockMap.
		// 3) lk3 or lk4 (whichever didn't execute in step 1) then executes and creates
		//    a new entry in lockMap and acquires a lock for the same resource.

		<-lk2ch
		lk3ok := <-lk3ch
		lk4ok := <-lk4ch

		if lk3ok && lk4ok {
			t.Fatalf("multiple locks acquired; iteration=%d, lk3=%t, lk4=%t", i, lk3ok, lk4ok)

     * released by calling {@link FileLock#close()}. This method blocks until the lock can be acquired.
     * <p>
     * Enable other processes to request access to the provided lock. Provided action runs when the lock access request is received
     * (it means that the lock is contended).
     *
     * @param target The file to be locked.
     * @param options The lock options.

	"time"
)

// A LRWMutex is a mutual exclusion lock with timeouts.
type LRWMutex struct {
	id          string
	source      string
	isWriteLock bool
	ref         int
	mu          sync.Mutex // Mutex to prevent multiple simultaneous locks
}

// NewLRWMutex - initializes a new lsync RW mutex.
func NewLRWMutex() *LRWMutex {
	return &LRWMutex{}
}

// Lock holds a write lock on lm.
//

      mu->lock_shared();
      variables[i]->set_shared_lock_held();
    } else {
      VLOG(4) << "Acquiring lock for variable "
              << reinterpret_cast<void*>(variable);
      mu->lock();
      variables[i]->set_lock_held();
    }
    prev = mu;
  }
  VLOG(4) << "Finished acquiring variable locks.";
  return absl::OkStatus();
}

Status LockVariables(absl::Span<VariableInfo> variables) {

import java.io.File;
import java.io.IOException;
import java.time.Duration;
import java.util.concurrent.locks.Lock;

class ExpectMethod implements ResourceHandler, BuildableExpectedRequest, ResourceExpectation, BlockingRequest {
    private final String method;
    private final String path;
    private final Duration timeout;
    private final Lock lock;

    private ResponseProducer producer = new ResponseProducer() {
        @Override