*/
  private interface CycleDetectingLock {

    /**
     * @return the {@link LockGraphNode} associated with this lock.
     */
    LockGraphNode getLockGraphNode();

    /**
     * @return {@code true} if the current thread has acquired this lock.
     */
    boolean isAcquiredByCurrentThread();
  }

  /**

   */
  private interface CycleDetectingLock {

    /**
     * @return the {@link LockGraphNode} associated with this lock.
     */
    LockGraphNode getLockGraphNode();

    /**
     * @return {@code true} if the current thread has acquired this lock.
     */
    boolean isAcquiredByCurrentThread();
  }

  /**