@Override
        public boolean equals(final Object o) {
            if (!(o instanceof GeoItemLayer.MapWriterGeoGroupKey<?>)) {
                return false;
            }
            final MapWriterGeoGroupKey<?> other = (MapWriterGeoGroupKey<?>) o;
            return Objects.equals(key, other.key) && index == other.index;
        }
Key class to be used for entries in MapWriter from a GeoGroup
main/src/main/java/cgeo/geocaching/unifiedmap/geoitemlayer/GeoItemLayer.java