private Map<Class<?>, Agreement> prepare(final Action action) { Map<Class<?>, Agreement> approvals = new HashMap<>(); for (Map.Entry<Class<?>, StoreCallback> entry : callbacks.entrySet()) { Class<?> store = entry.getKey(); StoreCallback callback = entry.getValue(); Agreement agreement = callback.voteFor(action); if (agreement.isApproved()) { approvals.put(store, agreement); } } return approvals; }