@Override
    public SortedSet<ZuulFilter<?, ?>> getFiltersByType(FilterType filterType) {
        SortedSet<ZuulFilter<?, ?>> set = hashFiltersByType.get(filterType);
        if (set != null) {
            return set;
        }

        set = new TreeSet<>(FILTER_COMPARATOR);

        for (ZuulFilter<?, ?> filter : filterRegistry.getAllFilters()) {
            if (filter.filterType().equals(filterType)) {
                set.add(filter);
            }
        }

        hashFiltersByType.putIfAbsent(filterType, set);
        return Collections.unmodifiableSortedSet(set);
    }
Returns a list of filters by the filterType specified
zuul-core/src/main/java/com/netflix/zuul/DynamicFilterLoader.java