private void setSingleQuickFilter(final Map<QuickFilter, Boolean> currentFilter, final Map<QuickFilter, Boolean> newFilter, final QuickFilter qf, final Action1<Boolean> setter) {
        final boolean currValue = TRUE.equals(currentFilter.get(qf));
        final boolean newValue = TRUE.equals(newFilter.get(qf));
        if (currValue == newValue) {
            return;
        }
        setter.call(newValue);
    }
Extracts quickfilter settings from this filter. For each quickfilter, an entry is returned
For each quickfilter, it is stored whether corresponding caches shall be shown (true) or not (false)
main/src/main/java/cgeo/geocaching/filters/core/GeocacheFilter.java