code: private Set<File> getReadLocks() {
          final Set<File> readLocks = new HashSet<File>();
          File[] lckFiles = this.lockPath.listFiles(lockFilter);
          for (final File lckFile : lckFiles) {
              if (lockFilter.isReaderLockFile(lckFile)) {
                  readLocks.add(lckFile);
              }
          }
  
          return readLocks;
      }
docs: Reads {@link LockAdviser#lockPath lock path directory} and finds the
  {@link File read lock files}, if any.
  
  @return the {@link Set set} of {@link read lock files}, or an empty
  {@link Set} if no read locks exist