public GeometryComparator getGeometryComparator(Bucket bucket) {
        switch (bucket) {
            case Gui:
                return guiList.getComparator();
            case Opaque:
                return opaqueList.getComparator();
            case Sky:
                return skyList.getComparator();
            case Transparent:
                return transparentList.getComparator();
            case Translucent:
                return translucentList.getComparator();
            default:
                throw new UnsupportedOperationException("Unknown bucket type: " + bucket);
        }
    }
Returns the current GeometryComparator used by the specified bucket,
 one of Gui, Opaque, Sky, Transparent, or Translucent.

@param bucket which Bucket to access (not null)
@return the pre-existing instance
jme3-core/src/main/java/com/jme3/renderer/queue/RenderQueue.java