protected void handleException()

in gremlin-server/src/main/java/org/apache/tinkerpop/gremlin/server/handler/AbstractSession.java [295:384]
78 lines of code
21 McCabe index (conditional complexity)

    protected void handleException(final SessionTask sessionTask, final Throwable t) throws SessionException {
        if (t instanceof SessionException) throw (SessionException) t;

        final Optional<Throwable> possibleSpecialException = determineIfSpecialException(t);
        if (possibleSpecialException.isPresent()) {
            final Throwable special = possibleSpecialException.get();
            final ResponseMessage.Builder specialResponseMsg = ResponseMessage.build(sessionTask.getRequestMessage()).
                    statusMessage(special.getMessage()).
                    statusAttributeException(special);
            if (special instanceof TemporaryException) {
                specialResponseMsg.code(ResponseStatusCode.SERVER_ERROR_TEMPORARY);
            } else if (special instanceof Failure) {
                final Failure failure = (Failure) special;
                specialResponseMsg.code(ResponseStatusCode.SERVER_ERROR_FAIL_STEP).
                        statusAttribute(Tokens.STATUS_ATTRIBUTE_FAIL_STEP_MESSAGE, failure.format());
            }
            throw new SessionException(special.getMessage(), specialResponseMsg.create());
        }

        final Throwable root = ExceptionHelper.getRootCause(t);

        if (root instanceof TimedInterruptTimeoutException) {
            // occurs when the TimedInterruptCustomizerProvider is in play
            final String msg = String.format("A timeout occurred within the script during evaluation of [%s] - consider increasing the limit given to TimedInterruptCustomizerProvider",
                    sessionTask.getRequestMessage().getRequestId());
            throw new SessionException(msg, root, ResponseMessage.build(sessionTask.getRequestMessage())
                    .code(ResponseStatusCode.SERVER_ERROR_TIMEOUT)
                    .statusMessage("Timeout during script evaluation triggered by TimedInterruptCustomizerProvider")
                    .create());
        }

        if (root instanceof TimeoutException) {
            final String errorMessage = String.format("Script evaluation exceeded the configured threshold for request [%s]",
                    sessionTask.getRequestMessage().getRequestId());
            throw new SessionException(errorMessage, root, ResponseMessage.build(sessionTask.getRequestMessage())
                    .code(ResponseStatusCode.SERVER_ERROR_TIMEOUT)
                    .statusMessage(t.getMessage())
                    .create());
        }

        if (root instanceof InterruptedException ||
                root instanceof TraversalInterruptedException ||
                root instanceof InterruptedIOException) {
            String msg = "Processing interrupted but the reason why was not known";
            switch (closeReason.get()) {
                case CHANNEL_CLOSED:
                    msg = "Processing interrupted because the channel was closed";
                    break;
                case SESSION_TIMEOUT:
                    msg = String.format("Session closed - %s - sessionLifetimeTimeout of %s ms exceeded", sessionId, actualTimeoutLengthWhenClosed);
                    break;
                case REQUEST_TIMEOUT:
                    msg = String.format("Evaluation exceeded timeout threshold of %s ms", actualTimeoutLengthWhenClosed);
                    break;
            }
            final ResponseStatusCode code = closeReason.get() == CloseReason.SESSION_TIMEOUT || closeReason.get() == CloseReason.REQUEST_TIMEOUT ?
                    ResponseStatusCode.SERVER_ERROR_TIMEOUT : ResponseStatusCode.SERVER_ERROR;
            throw new SessionException(msg, root, ResponseMessage.build(sessionTask.getRequestMessage())
                    .code(code)
                    .statusMessage(msg).create());
        }

        if (root instanceof MultipleCompilationErrorsException && root.getMessage().contains("Method too large") &&
                ((MultipleCompilationErrorsException) root).getErrorCollector().getErrorCount() == 1) {
            final String errorMessage = String.format("The Gremlin statement that was submitted exceeds the maximum compilation size allowed by the JVM, please split it into multiple smaller statements - %s", trimMessage(sessionTask.getRequestMessage()));
            logger.warn(errorMessage);
            throw new SessionException(errorMessage, root, ResponseMessage.build(sessionTask.getRequestMessage())
                    .code(ResponseStatusCode.SERVER_ERROR_EVALUATION)
                    .statusMessage(errorMessage)
                    .statusAttributeException(root).create());
        }

        // GroovyRuntimeException will hit a pretty wide range of eval type errors, like MissingPropertyException,
        // CompilationFailedException, MissingMethodException, etc. If more specific handling is required then
        // try to catch it earlier above.
        if (root instanceof GroovyRuntimeException ||
                root instanceof VerificationException ||
                root instanceof ScriptException) {
            throw new SessionException(root.getMessage(), root, ResponseMessage.build(sessionTask.getRequestMessage())
                    .code(ResponseStatusCode.SERVER_ERROR_EVALUATION)
                    .statusMessage(root.getMessage())
                    .statusAttributeException(root).create());
        }

        throw new SessionException(root.getClass().getSimpleName() + ": " + root.getMessage(), root,
                ResponseMessage.build(sessionTask.getRequestMessage())
                        .code(ResponseStatusCode.SERVER_ERROR)
                        .statusAttributeException(root)
                        .statusMessage(root.getMessage()).create());
    }