public ConfigurationImpl(ActionDefinition[] defs, String[] exts,
	ErrorHandler errh, VariableResolver resolver, FunctionMapper mapper) {
		_defs = defs != null ? defs: new ActionDefinition[0];
		_exts = exts != null ? exts: new String[0];
		_errh = errh != null ? errh: new ErrorHandlerImpl();
		_mapper = mapper;
		_resolver = resolver;
	}