synchronized(MultifacetedBrowsing.class){
if(mfb == null){ // creating new action state
if(MultifacetedBrowsing.getMdlOntology() == null){
MfbMediator mfbm = new MfbMediator();
Model outputmodel = mfbm.enhanceModel();
MultifacetedBrowsing.setMdlOntology(outputmodel);
}
mfb = new MultifacetedBrowsing(ModelFactory.createDefaultModel(), ModelFactory.createDefaultModel());