public List<Customer> filterStepbyStep(List<Customer> customers,
                                       String searchString,
                                       List<Tag> selectedTags,
                                       List<LocationId> selectedLocations) {
    List<Customer> filteredCustomers = new ArrayList<Customer>(customers);
    boolean searchStringNotEmpty = searchString != null && !searchString.trim().isEmpty();
    boolean locationsNotEmpty = selectedLocations != null && selectedLocations.size() > 0;
    boolean selectedTagsNotEmpty = selectedTags != null && selectedTags.size() > 0;

    filteredCustomers.removeIf(customer -> {
        boolean valid = true;

        //searchString
        if (valid && searchStringNotEmpty) {
            valid = customer.name.contains(searchString);
        }

        //locations
        if (valid && locationsNotEmpty) {
            valid = selectedLocations.stream().anyMatch(locationId -> locationId.equals(customer.locationId));
        }

        //tags
        if (valid && selectedTagsNotEmpty) {
            boolean tagValid = false;
            for (Tag selectedTag : selectedTags) {
                for (Tag customerTag : customer.getTags()) {
                    if (selectedTag == customerTag) {
                        tagValid = true;
                        break;
                    }
                }
                if (tagValid) {
                    break;
                }
            }
            valid = tagValid;
        }

        return !valid;
    });

    return filteredCustomers;
}

public List<Customer> filterWithLambda(List<Customer> customers,
                                       String searchString,
                                       List<Tag> selectedTags,
                                       List<LocationId> selectedLocations) {
    List<Customer> filteredCustomers = new ArrayList<Customer>(customers);
    boolean searchStringNotEmpty = searchString != null && !searchString.trim().isEmpty();
    boolean locationsNotEmpty = selectedLocations != null && selectedLocations.size() > 0;
    boolean selectedTagsNotEmpty = selectedTags != null && selectedTags.size() > 0;

    filteredCustomers.removeIf(customer -> {
        return (searchStringNotEmpty && !customer.name.contains(searchString))
                || (locationsNotEmpty && !selectedLocations.stream().anyMatch(locationId -> locationId.equals(customer.locationId)))
                || (selectedTagsNotEmpty && !selectedTags.stream().anyMatch(selectedTag ->
                      customer.getTags().stream().anyMatch(customerTag ->
                        selectedTag == customerTag)));
    });

    return filteredCustomers;
}