public CompletableFuture handle()

in com.microsoft.java.debug.core/src/main/java/com/microsoft/java/debug/core/adapter/handler/StepRequestHandler.java [64:143]
71 lines of code
15 McCabe index (conditional complexity)

    public CompletableFuture<Response> handle(Command command, Arguments arguments, Response response,
            IDebugAdapterContext context) {
        if (context.getDebugSession() == null) {
            return AdapterUtils.createAsyncErrorResponse(response, ErrorCode.EMPTY_DEBUG_SESSION, "Debug Session doesn't exist.");
        }

        long threadId = ((StepArguments) arguments).threadId;
        ThreadReference thread = DebugUtility.getThread(context.getDebugSession(), threadId);
        if (thread != null) {
            JdiExceptionReference exception = context.getExceptionManager().removeException(threadId);
            context.getStepResultManager().removeMethodResult(threadId);
            try {
                ThreadState threadState = new ThreadState();
                threadState.threadId = threadId;
                threadState.pendingStepType = command;
                threadState.stackDepth = thread.frameCount();
                threadState.stepLocation = getTopFrame(thread).location();
                threadState.eventSubscription = context.getDebugSession().getEventHub().events()
                    .filter(debugEvent -> (debugEvent.event instanceof StepEvent && debugEvent.event.request().equals(threadState.pendingStepRequest))
                        || (debugEvent.event instanceof MethodExitEvent && debugEvent.event.request().equals(threadState.pendingMethodExitRequest))
                        || debugEvent.event instanceof BreakpointEvent
                        || debugEvent.event instanceof ExceptionEvent)
                    .subscribe(debugEvent -> {
                        handleDebugEvent(debugEvent, context.getDebugSession(), context, threadState);
                    });

                if (command == Command.STEPIN) {
                    threadState.pendingStepRequest = DebugUtility.createStepIntoRequest(thread,
                        context.getStepFilters().allowClasses,
                        context.getStepFilters().skipClasses);
                } else if (command == Command.STEPOUT) {
                    threadState.pendingStepRequest = DebugUtility.createStepOutRequest(thread,
                        context.getStepFilters().allowClasses,
                        context.getStepFilters().skipClasses);
                } else {
                    threadState.pendingStepRequest = DebugUtility.createStepOverRequest(thread, null);
                }
                threadState.pendingStepRequest.enable();

                MethodExitRequest methodExitRequest = thread.virtualMachine().eventRequestManager().createMethodExitRequest();
                methodExitRequest.addThreadFilter(thread);
                methodExitRequest.addClassFilter(threadState.stepLocation.declaringType());
                if (thread.virtualMachine().canUseInstanceFilters()) {
                    try {
                        ObjectReference thisObject = getTopFrame(thread).thisObject();
                        if (thisObject != null) {
                            methodExitRequest.addInstanceFilter(thisObject);
                        }
                    } catch (Exception e) {
                        // ignore
                    }
                }
                methodExitRequest.setSuspendPolicy(EventRequest.SUSPEND_EVENT_THREAD);
                threadState.pendingMethodExitRequest = methodExitRequest;
                methodExitRequest.enable();

                DebugUtility.resumeThread(thread);

                ThreadsRequestHandler.checkThreadRunningAndRecycleIds(thread, context);
            } catch (IncompatibleThreadStateException ex) {
                // Roll back the Exception info if stepping fails.
                context.getExceptionManager().setException(threadId, exception);
                final String failureMessage = String.format("Failed to step because the thread '%s' is not suspended in the target VM.", thread.name());
                throw AdapterUtils.createCompletionException(
                    failureMessage,
                    ErrorCode.STEP_FAILURE,
                    ex);
            } catch (IndexOutOfBoundsException ex) {
                // Roll back the Exception info if stepping fails.
                context.getExceptionManager().setException(threadId, exception);
                final String failureMessage = String.format("Failed to step because the thread '%s' doesn't contain any stack frame", thread.name());
                throw AdapterUtils.createCompletionException(
                    failureMessage,
                    ErrorCode.STEP_FAILURE,
                    ex);
            }
        }

        return CompletableFuture.completedFuture(response);
    }