code: private void addCommandMember(String commandId, CommandGroup group) {
  
  		Assert.notNull(commandId, "commandId");
  		Assert.notNull(group, "group");
  
  		if (logger.isDebugEnabled()) {
  			logger.debug("adding command group member with id [" + commandId + "] to group [" + group.getId() + "]");
  		}
  
  		AbstractCommand command = null;
  
  		if (getCommandRegistry() != null) {
  			command = (AbstractCommand) getCommandRegistry().getCommand(commandId);
  			if (command != null) {
  				group.addInternal(command);
  			}
  		}
  
  		if (command == null) {
  			group.addLazyInternal(commandId);
  		}
  
  	}
docs: Adds the command object with the given id to the given command group. If
  a command registry has not yet been provided to this factory, the command
  id will be passed as a 'lazy placeholder' to the group instead.
  
  @param commandId The id of the command to be added to the group. This is
  expected to be in decoded form, i.e. any command prefixes have been
  removed. Must not be null.
  @param group The group that the commands will be added to. Must not be
  null.