FilterFactory2 ff = CommonFactoryFinder.getFilterFactory2(null);
Set<Identifier> ids = new HashSet<Identifier>();
ids.add(ff.featureId(validFid1));
ids.add(ff.featureId(validFid2));
ids.add(ff.featureId(invalidFid1));
ids.add(ff.featureId(invalidFid2));
Filter fidFilter = ff.id(ids);
final SimpleFeatureType schema = store.getSchema();
final String typeName = schema.getTypeName();
//get a property of type String to update its value by the given filter