presto-resource-group-managers/src/main/java/io/prestosql/plugin/resourcegroups/AbstractResourceConfigurationManager.java/AbstractResourceConfigurationManager/buildSelectors
class AbstractResourceConfigurationManager:    protected List<ResourceGroupSelector> buildSelectors(ManagerSpec managerSpec)
    {
        ImmutableList.Builder<ResourceGroupSelector> selectors = ImmutableList.builder();
        for (SelectorSpec spec : managerSpec.getSelectors()) {
            validateSelectors(managerSpec.getRootGroups(), spec);
            selectors.add(new StaticSelector(
                    spec.getUserRegex(),
                    spec.getSourceRegex(),
                    spec.getClientTags(),
                    spec.getResourceEstimate(),
                    spec.getQueryType(),
                    spec.getGroup()));
        }
        return selectors.build();
    }