T execute()

in src/main/java/software/amazon/qldb/QldbSession.java [56:123]
65 lines of code
10 McCabe index (conditional complexity)

    <T> T execute(Executor<T> executor) {
        Transaction txn = null;
        String txnId = "None";
        try {
            txn = this.startTransaction();
            txnId = txn.getTransactionId();
            T returnedValue = executor.execute(new TransactionExecutor(txn));
            if (returnedValue instanceof StreamResult) {
                // If someone accidentally returned a StreamResult object which would become invalidated by the
                // commit, automatically buffer it to allow them to use the result anyway.
                returnedValue = (T) new BufferedResult((Result) returnedValue);
            }
            txn.commit();
            return returnedValue;
        } catch (InvalidSessionException ise) {
            boolean isAborted = false;
            boolean transactionExpired = ise.getMessage().matches("Transaction.*has expired.*");
            if (transactionExpired) {
                isAborted = this.tryAbort(txn);
            }
            throw new ExecuteException(
                    ise,
                    !transactionExpired,
                    isAborted,
                    true,
                    txnId
            );
        } catch (OccConflictException oce) {
            throw new ExecuteException(
                    oce,
                    true,
                    true,
                    false,
                    txnId
            );
        } catch (QldbSessionException qse) {
            boolean retryable = (qse.statusCode() == HttpStatus.SC_INTERNAL_SERVER_ERROR)
                    || (qse.statusCode() == HttpStatus.SC_SERVICE_UNAVAILABLE);
            throw new ExecuteException(
                    qse,
                    retryable,
                    this.tryAbort(txn),
                    false,
                    txnId
            );
        } catch (SdkClientException sce) {
            // SdkClientException means that client couldn't reach out QLDB so transaction should be retried.
            throw new ExecuteException(
                    sce,
                    true,
                    this.tryAbort(txn),
                    false,
                    txnId
            );
        } catch (RuntimeException re) {
            throw new ExecuteException(
                    re,
                    false,
                    this.tryAbort(txn),
                    false,
                    txnId
            );
        } finally {
            if (txn != null) {
                txn.internalClose();
            }
        }
    }