code: private synchronized boolean addPeer(final PeerInfo peer) {
  
  		final String uuid = peer.getUuid();
  
  		if (!peers.containsKey(uuid)) {
  
  			peers.put(uuid, peer);
  
  			peer.setLastSeen(System.currentTimeMillis());
  			onAddPeer(peer);
  
  			return true;
  		}
  
  		// not added
  		return false;
  	}
docs: ----- private methods -----