code: public void setPrefixConfig(final PrefixConfig config) {
  		lock.writeLock().lock();
  		try {
  			if (config == null) {
  				prefixes = EmptyPrefix.INSTANCE;
  			} else {
  				prefixes = config;
  			}
  		} finally {
  			lock.writeLock().unlock();
  		}
  	}
docs: Sets the prefix config.
  
  @param config
  the new prefix config