txn_lock.java

private void initSchema() {
        doWithLock("cassalog", () -> {
                SchemaService schemaService = new SchemaService();
                schemaService.run(session, keyspace, Boolean.parseBoolean(resetDb));
                session.execute("USE " + keyspace);
        });
}
    private void doWithLock(String key, Runnable runnable) {
        AdvancedCache<String, String> cache = locksCache.getAdvancedCache();
        TransactionManager transactionManager = cache.getTransactionManager();
        try {
            boolean acquired = false;
            while (!acquired) {
                try {
                    transactionManager.begin();
                    acquired = cache.lock(key);
                } catch (TimeoutException e) {
                    log.infof("Timed out while trying to acquire lock [%s]", key);
                    transactionManager.rollback();
                }
            }
            runnable.run();
            transactionManager.commit();
        } catch (Exception e) {
            try {
                transactionManager.rollback();
            } catch (SystemException e1) {
            }
        }
    }