public static String createTagQuickFilterInput(final Set<String> tags) {
        final String quickFilterInput;
        if (NullSafe.hasItems(tags)) {
            // Add a space on the end so the user is ready to type any extra terms
            quickFilterInput = tags.stream()
                    .map(tag ->
                            ExplorerTreeFilter.FIELD_DEF_TAG.getFilterQualifier() + ":" + tag)
                    .collect(Collectors.joining(" ")) + " ";
        } else {
            quickFilterInput = null;
        }
        return quickFilterInput;
    }
Turns 'cat dog' into 'tag:cat tag:dog '

@return A qualified quick filter input string or null if tags is empty/null
stroom-core-shared/src/main/java/stroom/explorer/shared/ExplorerTreeFilter.java