public boolean containsKey(Object key) {
   return store.get(propertyKey(key)) != null;
 }
 public Object get(Object key) {
   Triple t = store.get(propertyKey(key));
   return t == null ? null : t.getValue();
 }
 public Object remove(Object key) {
   return store.remove(store.get(propertyKey(key)));
 }