/**
  * Marks the given node as offline if free disk space is below the configured threshold.
  *
  * @param c the node
  * @return the free space
  * @since 1.521
  */
 @Restricted(NoExternalUse.class)
 public DiskSpace markNodeOfflineIfDiskspaceIsTooLow(Computer c) {
   DiskSpace size = (DiskSpace) super.data(c);
   if (size != null && size.size < getThresholdBytes()) {
     size.setTriggered(this.getClass(), true);
     if (getDescriptor().markOffline(c, size)) {
       LOGGER.warning(Messages.DiskSpaceMonitor_MarkedOffline(c.getName()));
     }
   }
   return size;
 }
 public long getThresholdBytes() {
   if (freeSpaceThreshold == null)
     return DEFAULT_THRESHOLD; // backward compatibility with the data format that didn't have
   // 'freeSpaceThreshold'
   try {
     return DiskSpace.parse(freeSpaceThreshold).size;
   } catch (ParseException e) {
     return DEFAULT_THRESHOLD;
   }
 }
 @DataBoundConstructor
 public AbstractDiskSpaceMonitor(String threshold) throws ParseException {
   this.freeSpaceThreshold = threshold;
   DiskSpace.parse(threshold); // make sure it parses
 }