code: public boolean canHitMemcached(final String sessionId) {
  		if ( isEncodeNodeIdInSessionId() ) {
  	        final String nodeId = _sessionIdFormat.extractMemcachedId( sessionId );
  	        if ( nodeId == null ) {
  	            LOG.debug( "The sessionId does not contain a nodeId so that the memcached node could not be identified." );
  	            return false;
  	        }
  			if ( !_nodeIdService.isNodeAvailable( nodeId ) ) {
  	            LOG.debug( "The node "+ nodeId +" is not available, therefore " + sessionId + " cannot be loaded from this memcached." );
  	            return false;
  	        }
  		}
  		return true;
  	}
docs: Can be used to determine if the given sessionId can be used to interact with memcached.
  This also checks if the related memcached is available.
  @see #isValidForMemcached(String)