I am trying to unit test Microsoft.Azure.ServiceBus(3.3.0) topic and subscription functionality. But I am not interested in testing Microsoft.Azure.ServiceBus classes, but more how mock Send a message to the topic and check if that message exists on that specific topic with a subscription.
At the moment I have a super simple Publisher class with one method SendAsync. As you can see here:
// Pseudo code, not full implementation!
public class Publisher : IPublisher
{
private readonly ManagementClient _managementClient;
private readonly TopicClientFactory _topicClientFactory;
public Publisher(ManagementClient managementClient, TopicClientFactory topicClientFactory)
{
_managementClient = managementClient;
_topicClientFactory = topicClientFactory;
}
public async Task SendAsync(myModel message)
{
ITopicClient topicClient = _topicClientFactory.Create("MyTopic");
// encode message using message
Message message = new Message(encodedMessage);
await topicClient.SendAsync(message); // trying to mock & test this!
await topicClient.CloseAsync();
}
}
Factory has only one method. When creating a new TopicClient using factory I am also returning the ITopicClient interface. Not sure if that helps.
// Pseudo code, not full implementation!
public class TopicClientFactory
{
public ITopicClient Create(string topicPath)
{
return new TopicClient("MyConnectionString", topicPath);
}
}
Unit test:
[Fact]
public async Task Name()
{
var managementClientMock = new Mock<ManagementClient>("MyConnectionString");
var topicClientFactoryMock = new Mock<TopicClientFactory>("MyConnectionString");
// mock topic client's send method!
var topicClientMock = new Mock<ITopicClient>();
topicClientMock.Setup(x =>
x.SendAsync(It.IsAny<Message>())).Returns(Task.CompletedTask); // .Verifiable();
// pass mocked topicClient to mocked factory
topicClientFactoryMock.Setup(tc => tc.Create("topicPath")).Returns(topicClientMock.Object);
var publisher = new Publisher(managementClientMock.Object, topicClientFactoryMock.Object);
await publisher.SendAsync(command);
// how to test if message has been sent?
}
Related
I recently started learning Unit Testing and now have the requirement write unit tests using Xunit and Moq for dot net core application.
I can write some very basic but when it comes to write them for complex classes , I am kind of stuck.
Below is the class I will be writing tests for.
public class AgeCategoryRequestHandler : IInventoryRequestHandler<InventoryRequest, HandlerResult>
{
private readonly IRepositoryResolver _repositoryResolver;
Hotels.HBSI.Logging.ILogger logger;
public AgeCategoryRequestHandler(IRepositoryResolver repositoryResolver, Hotels.HBSI.Logging.ILogger iLogger)
{
_repositoryResolver = repositoryResolver;
logger = iLogger;
}
public async Task<HandlerResult> Run(InventoryRequest inventoryRequest)
{
var result = await ProcessRequest(inventoryRequest);
return CreateResponse(inventoryRequest, result);
}
private async Task<int> ProcessRequest(InventoryRequest inventoryRequest)
{
logger.Info("AgeCategory requesthandler processrequest start");
var repository = _repositoryResolver.ResolveEstabAgeCategory();
if (repository is not null)
{
return await repository.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories)
.ConfigureAwait(false);
}
logger.Info("AgeCategory requesthandler processrequest complete");
return InernalError.reponotfound;
}
public HandlerResult CreateResponse(InventoryRequest inventoryRequest, int resultCount)
{
var requestCount = inventoryRequest.EstabAgeCategories.Count;
var handlerResult = new HandlerResult() { Id = RequestHandlerEnum.AgeCategrory.ToInt() };
if (requestCount > 0 && resultCount < requestCount)
{
handlerResult.IsSuccess = false;
handlerResult.ErrorCode = OTAErrorType.InvalidAgeCategory.ToInt();
}
else if (requestCount > 0 || requestCount == resultCount)
{
handlerResult.IsSuccess = true;
handlerResult.ErrorCode = 0;
}
return handlerResult;
}
}
Just to start , IRepositoryResolver and ILogger are in the constructor so I have created mock for these but unable to go beyond that as I am still in initial phase of learning.
Could someone explain me the steps/approach to accomplish this?.
Edit : What I have done so far is below ( can't figure out what are the things to be done and where to start or write )
Edit 2 : Did some more modifications to my test code , can someone comment if I am in right direction ? what else can I test ?
public class AgeCategoryRequestHandlerTest
{
private AgeCategoryRequestHandler _ageCategoryRequestHandler;
private readonly Mock<AgeCategoryRequestHandler> _ageCategory = new Mock<AgeCategoryRequestHandler>();
private readonly Mock<Hotels.HBSI.Logging.ILogger> _mockLogger = new Mock<Hotels.HBSI.Logging.ILogger>();
private readonly Mock<IRepositoryResolver> _mockRepositoryResolver = new Mock<IRepositoryResolver>();
public AgeCategoryRequestHandlerTest()
{
_ageCategoryRequestHandler = new AgeCategoryRequestHandler(_mockRepositoryResolver.Object, _mockLogger.Object);
}
[Fact]
public async void Testtt()
{
var fixture = new Fixture();
var inventory = fixture.Create<InventoryRequest>();
var hndlr = fixture.Create<HandlerResult>();
hndlr.ErrorCode = 0;
int resultCount = 3;
await _ageCategoryRequestHandler.Run(inventory);
HandlerResult response = _ageCategoryRequestHandler.CreateResponse(inventory, resultCount);
Assert.Equal(hndlr.ErrorCode, response.ErrorCode);
}
Tried running Chris B suggested code , was getting type conversion error EstabAgeCategories = new List<int>
Now I have used fixture for creating automatic objects and did some assert values. Below is the code sample
var fixture = new Fixture();
var inventoryRequest = fixture.Create<InventoryRequest>();
_mockRepository
.Setup(x => x.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories))
.ReturnsAsync(6);
_mockRepositoryResolver
.Setup(x => x.ResolveEstabAgeCategory())
.Returns(_mockRepository.Object);
// act
var result = await _ageCategoryRequestHandler.Run(inventoryRequest);
// assert
_mockRepository
.Verify(x => x.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories), Times.Once);
Assert.True(result.Id == 6);
Assert.True(result.ErrorCode == 0);
Assert.True(result.IsSuccess);
From the unit test code you've posted, it looks like you are getting confused on what to test.
Look at your class and identify your "public" interface i.e. what methods can be called from other parts of your code. You should really only test public methods. Private methods are usually tested via public methods.
Looking at AgeCategoryRequestHandler, you have two public methods - Run and CreateResponse. I would question whether CreateResponse needs to be public but we'll leave it for now. For each of these methods, you want to be asserting that the returned value is what you expect given the input value.
private AgeCategoryRequestHandler _ageCategoryRequestHandler;
// Not needed
private readonly Mock<AgeCategoryRequestHandler> _ageCategory = new Mock<AgeCategoryRequestHandler>();
private readonly Mock<Hotels.HBSI.Logging.ILogger> _mockLogger = new Mock<Hotels.HBSI.Logging.ILogger>();
private readonly Mock<IRepositoryResolver> _mockRepositoryResolver = new Mock<IRepositoryResolver>();
public AgeCategoryRequestHandlerTest()
{
_ageCategoryRequestHandler = new AgeCategoryRequestHandler(_mockRepositoryResolver.Object, _mockLogger.Object);
}
The set up of the unit test is going the right way - you have created mocks for your dependencies but I see you have created a mock for the class you are trying to test - this is not needed and can be removed. You want to be testing the actual class itself which you are initializing in the constructor.
public async Task<HandlerResult> Run(InventoryRequest inventoryRequest)
{
var result = await ProcessRequest(inventoryRequest);
return CreateResponse(inventoryRequest, result);
}
private async Task<int> ProcessRequest(InventoryRequest inventoryRequest)
{
_logger.LogInformation("AgeCategory requesthandler processrequest start");
var repository = _repositoryResolver.ResolveEstabAgeCategory();
if (repository != null)
{
return await repository.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories).ConfigureAwait(false);
}
_logger.LogInformation("AgeCategory requesthandler processrequest complete");
return 0;
}
We can test the public Run method by looking at the method and seeing what it is going to do when executed. Firstly, it's going to call a private method ProcessRequest. Inside ProcessRequest, the IRepositoryResolver dependency is going to be used. This means we need to "set up" this dependency in our unit test to satisfy the if (repository != null) condition.
I assume the IRepositoryResolver returns another interface (?) - something like:
public interface IRepository
{
Task<int> InsertUpdateEstabAgeCategoryDetail(List<int> x);
}
So in your unit test, you need to create a mock for the repository being returned from IRepositoryResolver:
private readonly Mock<IRepository> _mockRepository = new Mock<IRepository>();
Then, you need to set up the mock IRepositoryResolver to return the mock repository above:
_mockRepositoryResolver
.Setup(x => x.ResolveEstabAgeCategory())
.Returns(_mockRepository.Object);
This is to satisfy the if (repository != null) condition.
_mockRepository
.Setup(x => x.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories))
.ReturnsAsync(6);
Next, you need to set up the InsertUpdateEstabAgeCategoryDetail() method on the mock repository to return a value. This value is being returned by ProcessRequest() and then used to call CreateResponse(inventoryRequest, result) as the result parameter.
if (requestCount > 0 && resultCount < requestCount)
{
handlerResult.IsSuccess = false;
handlerResult.ErrorCode = (int)OTAErrorType.InvalidAgeCategory;
}
else if (requestCount > 0 || requestCount == resultCount)
{
handlerResult.IsSuccess = true;
handlerResult.ErrorCode = 0;
}
Now you can look at the CreateResponse method and by setting different values for inventoryRequest.EstabAgeCategories and setting up the mock _mockRepository.Setup(x => x.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories)).ReturnsAsync(6); to return different values, you can satisfy the different paths through the if statement.
CreateResponse is returning an instance of HandlerResult which in turn is being returned by Task<HandlerResult> Run. This is the returned object you want to make assertions on.
One of the unit test cases might look like this (I have not tested it myself):
[Fact]
public async Task GivenInventoryRequest_WhenRun_ThenHandlerResultReturned()
{
// arrange
var inventoryRequest = new InventoryRequest
{
EstabAgeCategories = new List<int>
{
1, 2, 3, 4, 5
}
};
_mockRepository
.Setup(x => x.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories))
.ReturnsAsync(6);
_mockRepositoryResolver
.Setup(x => x.ResolveEstabAgeCategory())
.Returns(_mockRepository.Object);
// act
var result = await _ageCategoryRequestHandler.Run(inventoryRequest);
// assert
_mockRepository
.Verify(x => x.InsertUpdateEstabAgeCategoryDetail(inventoryRequest.EstabAgeCategories), Times.Once);
Assert.True(result.Id == 0);
Assert.True(result.ErrorCode == 0);
Assert.False(result.IsSuccess);
}
I have this flow that I am trying to test but nothing works as expected. The flow itself works well but testing seems a bit tricky.
This is my flow:
#Configuration
#RequiredArgsConstructor
public class FileInboundFlow {
private final ThreadPoolTaskExecutor threadPoolTaskExecutor;
private String filePath;
#Bean
public IntegrationFlow fileReaderFlow() {
return IntegrationFlows.from(Files.inboundAdapter(new File(this.filePath))
.filterFunction(...)
.preventDuplicates(false),
endpointConfigurer -> endpointConfigurer.poller(
Pollers.fixedDelay(500)
.taskExecutor(this.threadPoolTaskExecutor)
.maxMessagesPerPoll(15)))
.transform(new UnZipTransformer())
.enrichHeaders(this::headersEnricher)
.transform(Message.class, this::modifyMessagePayload)
.route(Map.class, this::channelsRouter)
.get();
}
private String channelsRouter(Map<String, File> payload) {
boolean isZip = payload.values()
.stream()
.anyMatch(file -> isZipFile(file));
return isZip ? ZIP_CHANNEL : XML_CHANNEL; // ZIP_CHANNEL and XML_CHANNEL are PublishSubscribeChannel
}
#Bean
public SubscribableChannel xmlChannel() {
var channel = new PublishSubscribeChannel(this.threadPoolTaskExecutor);
channel.setBeanName(XML_CHANNEL);
return channel;
}
#Bean
public SubscribableChannel zipChannel() {
var channel = new PublishSubscribeChannel(this.threadPoolTaskExecutor);
channel.setBeanName(ZIP_CHANNEL);
return channel;
}
//There is a #ServiceActivator on each channel
#ServiceActivator(inputChannel = XML_CHANNEL)
public void handleXml(Message<Map<String, File>> message) {
...
}
#ServiceActivator(inputChannel = ZIP_CHANNEL)
public void handleZip(Message<Map<String, File>> message) {
...
}
//Plus an #Transformer on the XML_CHANNEL
#Transformer(inputChannel = XML_CHANNEL, outputChannel = BUS_CHANNEL)
private List<BusData> xmlFileToIngestionMessagePayload(Map<String, File> xmlFilesByName) {
return xmlFilesByName.values()
.stream()
.map(...)
.collect(Collectors.toList());
}
}
I would like to test multiple cases, the first one is checking the message payload published on each channel after the end of fileReaderFlow.
So I defined this test classe:
#SpringBootTest
#SpringIntegrationTest
#ExtendWith(SpringExtension.class)
class FileInboundFlowTest {
#Autowired
private MockIntegrationContext mockIntegrationContext;
#TempDir
static Path localWorkDir;
#BeforeEach
void setUp() {
copyFileToTheFlowDir(); // here I copy a file to trigger the flow
}
#Test
void checkXmlChannelPayloadTest() throws InterruptedException {
Thread.sleep(1000); //waiting for the flow execution
PublishSubscribeChannel xmlChannel = this.getBean(XML_CHANNEL, PublishSubscribeChannel.class); // I extract the channel to listen to the message sent to it.
xmlChannel.subscribe(message -> {
assertThat(message.getPayload()).isInstanceOf(Map.class); // This is never executed
});
}
}
As expected that test does not work because the assertThat(message.getPayload()).isInstanceOf(Map.class); is never executed.
After reading the documentation I didn't find any hint to help me solved that issue. Any help would be appreciated! Thanks a lot
First of all that channel.setBeanName(XML_CHANNEL); does not effect the target bean. You do this on the bean creation phase and dependency injection container knows nothing about this setting: it just does not consult with it. If you really would like to dictate an XML_CHANNEL for bean name, you'd better look into the #Bean(name) attribute.
The problem in the test that you are missing the fact of async logic of the flow. That Files.inboundAdapter() works if fully different thread and emits messages outside of your test method. So, even if you could subscribe to the channel in time, before any message is emitted to it, that doesn't mean your test will work correctly: the assertThat() will be performed on a different thread. Therefore no real JUnit report for your test method context.
So, what I'd suggest to do is:
Have Files.inboundAdapter() stopped in the beginning of the test before any setup you'd like to do in the test. Or at least don't place files into that filePath, so the channel adapter doesn't emit messages.
Take the channel from the application context and if you wish subscribe or use a ChannelInterceptor.
Have an async barrier, e.g. CountDownLatch to pass to that subscriber.
Start the channel adapter or put file into the dir for scanning.
Wait for the async barrier before verifying some value or state.
In ASP.NET Core 5 I had a custom Action Result as follows:
public class ErrorResult : ActionResult {
private readonly IList<Error> _errors;
public ErrorResult(IList<Error> errors) {
_errors = errors;
}
public override async Task ExecuteResultAsync(ActionContext context) {
// Code that creates Response
await result.ExecuteResultAsync(context);
}
}
Then on a Controller action I would have:
return new ErrorResult(errors);
How to do something similar in NET 6 Minimal APIs?
I have been looking at it and I think I should implement IResult.
But I am not sure if that is the solution or how to do it.
I have recently been playing around with minimal APIs and and working on global exception handling. Here is what I have come up with so far.
Create a class implementation of IResult
Create a constructor which will take an argument of the details you want going into your IResult response. APIErrorDetails is a custom implementation of mine similar to what you'd see in ProblemDetails in MVC. Method implementation is open to whatever your requirements are.
public class ExceptionAllResult : IResult
{
private readonly ApiErrorDetails _details;
public ExceptionAllResult(ApiErrorDetails details)
{
_details = details;
}
public async Task ExecuteAsync(HttpContext httpContext)
{
var jsonDetails = JsonSerializer.Serialize(_details);
httpContext.Response.ContentType = MediaTypeNames.Application.Json;
httpContext.Response.ContentLength = Encoding.UTF8.GetByteCount(jsonDetails);
httpContext.Response.StatusCode = _details.StatusCode;
await httpContext.Response.WriteAsync(jsonDetails);
}
}
Return result in your exception handling middleware in your Program.cs file.
app.UseExceptionHandler(
x =>
{
x.Run(
async context =>
{
// https://learn.microsoft.com/en-us/aspnet/core/fundamentals/error-handling?view=aspnetcore-6.0
var exceptionFeature = context.Features.Get<IExceptionHandlerPathFeature>();
// Whatever you want for null handling
if (exceptionFeature is null) throw new Exception();
// My result service for creating my API details from the HTTP context and exception. This returns the Result class seen in the code snippet above
var result = resultService.GetErrorResponse(exceptionFeature.Error, context);
await result.ExecuteAsync(context); // returns the custom result
});
}
);
If you still want to use MVC (Model-View-Controller), you still can use Custom ActionResult.
If you just want to use Minimal APIs to do the response, then you have to implement IResult, Task<IResult> or ValueTask<IResult>.
app.MapGet("/hello", () => Results.Ok(new { Message = "Hello World" }));
The following example uses the built-in result types to customize the response:
app.MapGet("/api/todoitems/{id}", async (int id, TodoDb db) =>
await db.Todos.FindAsync(id)
is Todo todo
? Results.Ok(todo)
: Results.NotFound())
.Produces<Todo>(StatusCodes.Status200OK)
.Produces(StatusCodes.Status404NotFound);
You can find more IResult implementation samples here: https://github.com/dotnet/aspnetcore/tree/main/src/Http/Http.Results/src
Link: Minimal APIs overview | Microsoft Docs
I have a hierarchy of actors in Akka.Net and am wondering whether I've chosen the right way to do something, or if there are better/simpler ways to achieve what I want.
My specific example is that I'm constructing a User actor in response to a user logging into the system, and when constructing this actor there are two pieces of data I need in order to complete the construction of the actor.
If this were regular .NET code I might have something like the following...
public Task<User> LoadUserAsync (string username)
{
IProfileService profileService = ...;
IMessageService messageService = ...;
var loadProfileTask = profileService.GetUserProfileAsync(username);
var loadMessagesTask = messageService.GetMessagesAsync(username);
Task.WaitAll(loadProfileTask, loadMessagesTask);
// Now construct the user from the result of both tasks
var user = new User
{
Profile = loadProfileTask.Result,
Messages = loadMessagesTask.Result
}
return Task.FromResult(user);
}
Here I use WaitAll to wait for the subordinate tasks to complete, and let them run concurrently.
My question is - if I wanted to do the same in Akka.Net, would the following be the most regular way to do this? Pictorially I've created the following...
When I create my User actor, I then construct a (temporary) User Loader Actor, whose job it is to get the full user details by calling to the Profile actor and the Messages actor. The leaf actors that get the data are as follows...
public class UserProfileLoader : ReceiveActor
{
public UserProfileLoader()
{
Receive<LoadUserRequest>(msg =>
{
// Load the user profile from somewhere
var profile = new UserProfile();
// And respond to the Sender
Sender.Tell(profile);
Self.Tell(PoisonPill.Instance);
});
}
}
public class UserMessagesLoader : ReceiveActor
{
public UserMessagesLoader()
{
Receive<LoadUserRequest>(msg =>
{
// Load the messages from somewhere
var messages = new List<Message>();
// And respond to the Sender
Sender.Tell(messages);
Self.Tell(PoisonPill.Instance);
});
}
}
It doesn't really matter where they get the data from for this discussion, but both simply respond to a request by returning some data.
Then I have the actor that coordinates the two data gathering actors...
public class UserLoaderActor : ReceiveActor
{
public UserLoaderActor()
{
Receive<LoadUserRequest>(msg => LoadProfileAndMessages(msg));
Receive<UserProfile>(msg =>
{
_profile = msg;
FinishIfPossible();
});
Receive<List<Message>>(msg =>
{
_messages = msg;
FinishIfPossible();
});
}
private void LoadProfileAndMessages(LoadUserRequest msg)
{
_originalSender = Sender;
Context.ActorOf<UserProfileLoader>().Tell(msg);
Context.ActorOf<UserMessagesLoader>().Tell(msg);
}
private void FinishIfPossible()
{
if ((null != _messages) && (null != _profile))
{
_originalSender.Tell(new LoadUserResponse(_profile, _messages));
Self.Tell(PoisonPill.Instance);
}
}
private IActorRef _originalSender;
private UserProfile _profile;
private List<Message> _messages;
}
This just creates the two subordinate actors, sends them a message to get cracking, and then waits for both to respond before sending back all the data that's been gathered to the original requestor.
So, does this seem like a reasonable way to coordinate two disparate responses, in order to combine them? Is there an easier way to do this than craft it up myself?
Thanks in advance for your responses!
Thanks folks, so I've now simplified the actor significantly into the following, based on both Roger and Jeff's suggestions...
public class TaskBasedUserLoader : ReceiveActor
{
public TaskBasedUserLoader()
{
Receive<LoadUserRequest>(msg => LoadProfileAndMessages(msg));
}
private void LoadProfileAndMessages(LoadUserRequest msg)
{
var originalSender = Sender;
var loadPreferences = this.LoadProfile(msg.UserId);
var loadMessages = this.LoadMessages(msg.UserId);
Task.WhenAll(loadPreferences, loadMessages)
.ContinueWith(t => new UserLoadedResponse(loadPreferences.Result, loadMessages.Result),
TaskContinuationOptions.AttachedToParent & TaskContinuationOptions.ExecuteSynchronously)
.PipeTo(originalSender);
}
private Task<UserProfile> LoadProfile(string userId)
{
return Task.FromResult(new UserProfile { UserId = userId });
}
private Task<List<Message>> LoadMessages(string userId)
{
return Task.FromResult(new List<Message>());
}
}
The LoadProfile and LoadMessages methods will ultimately call a repository to get the data, but for now I have a succinct way to do what I wanted.
Thanks again!
IMHO that's a valid process, as you fork action and then join it.
BTW you could use this.Self.GracefulStop(new TimeSpan(1)); instead of sending poison pill.
You could use a combination of Ask, WhenAll and PipeTo:
var task1 = actor1.Ask<Result1>(request1);
var task2 = actor2.Ask<Result2>(request2);
Task.WhenAll(task1, task2)
.ContinueWith(_ => new Result3(task1.Result, task2.Result))
.PipeTo(Self);
...
Receive<Result3>(msg => { ... });
I am learning about Spring-Integration and have a basic understanding about Gateway and Service-Activators. I love the concept of Gateway. Spring Integration generates the proxy for gateway at run-time. This proxy hides all the messaging details from the consumer of the gateway. In addition, the generated proxy might also be co-relating request and reply.
With the objective of learning, I set out to implement request and reply correlation using raw Spring Integration features and not using Gateway. I am able to set the correlation identifier in the request header, but not able to specify correlation identifier while receiving reply for the channel. The following (at the end of the question) is the code snippet for the same. Also how does the correlation stuff works against a message broker (e.g. RabbitMQ)? Does RabbitMQ provides an ability to retrieve a message with a specific header (correlation identifier) in it?
public class RemoteProxyCalculatorService implements CalculatorService
{
public int Square(int n)
{
UUID uuid = SendRequest(n, "squareRequestChannel");
int squareOfn = ReceiveReply("squareReplyChannel", uuid);
return squareOfn;
}
private <T> UUID SendRequest(T payload, String requestChannel)
{
UUID requestID = UUID.randomUUID();
Message<T> inputMessage = MessageBuilder.withPayload(payload)
.setCorrelationId(requestID)
.build();
MessageChannel channel = (MessageChannel)context.getBean(requestChannel, MessageChannel.class);
channel.send(inputMessage);
return requestID;
}
#SuppressWarnings("unchecked")
private <T> T ReceiveReply(String replyChannel, UUID requestID)
{
//How to consume requestID so as to receive only the reply related to the request posted by this thread
PollableChannel channel = (PollableChannel)context.getBean(replyChannel);
Message<?> groupMessage = channel.receive();
return (T)groupMessage.getPayload();
}
private ClassPathXmlApplicationContext context;
}
Thanks.
The simplest way to correlate within an app doesn't even require a correlationId header. Instead you can create a QueueChannel instance (that you don't share) and provide that as s the replyChannel header on the Message you send. Whatever downstream component ultimately responds, it will find that header in the Message.
Regarding RabbitMQ, our outbound-gateway simply applies a similar technique, but using the replyTo property of the AMQP Message.
Hope that helps.
-Mark
Problem is with common reply channel. The solution (Mark suggested the similar) will look like this.
public class RemoteProxyCalculatorService
{
public int Square(int n)
{
PollableChannel replyChannel = SendRequest(n, "squareRequestChannel");
int squareOfn = ReceiveReply(replyChannel);
return squareOfn;
}
private <T> PollableChannel SendRequest(T payload, String requestChannel)
{
UUID requestID = UUID.randomUUID();
QueueChannel replyQueueChannel = new QueueChannel();
Message<T> inputMessage = MessageBuilder.withPayload(payload)
.setCorrelationId(requestID)
.setReplyChannel(replyQueueChannel)
.build();
MessageChannel channel = context.getBean(requestChannel, MessageChannel.class);
channel.send(inputMessage);
return replyQueueChannel;
}
#SuppressWarnings("unchecked")
private <T> T ReceiveReply(PollableChannel replyChannel)
{
Message<?> groupMessage = replyChannel.receive();
return (T) groupMessage.getPayload();
}
private ClassPathXmlApplicationContext context;
}
If you want to use common reply channel then I think this is what you are looking for.
public class RemoteProxyCalculatorService
{
public int Square(int n)
{
PollableChannel replyChannel = SendRequest(n, "squareRequestChannel");
int squareOfn = ReceiveReply(replyChannel);
return squareOfn;
}
private <T> PollableChannel SendRequest(T payload, String requestChannel)
{
UUID requestID = UUID.randomUUID();
Message<T> inputMessage = MessageBuilder.withPayload(payload)
.setCorrelationId(requestID)
.setReplyChannel(myMessageHandler.getSubscribedChannel())
.build();
// Create a Pollable channel for two things
// 1. Pollable channel is where this thread should look for reply.
QueueChannel replyQueueChannel = new QueueChannel();
// 2. Message Handler will send reply to this Pollable channel once it receives the reply using correlation Id.
myMessageHandler.add(requestID, replyQueueChannel);
MessageChannel channel = context.getBean(requestChannel, MessageChannel.class);
channel.send(inputMessage);
return replyQueueChannel;
}
#SuppressWarnings("unchecked")
private <T> T ReceiveReply(PollableChannel replyChannel)
{
Message<?> groupMessage = replyChannel.receive();
return (T) groupMessage.getPayload();
}
private ClassPathXmlApplicationContext context;
#Autowired
private MyMessageHandler myMessageHandler;
}
/**
* Message Handler
*
*/
public class MyMessageHandler implements MessageHandler
{
private final Map<Object, MessageChannel> idChannelsMap = new TreeMap<>();
private final Object lock = new Object();
private final SubscribableChannel subscribedChannel;
public MyMessageHandler(SubscribableChannel subscribedChannel)
{
this.subscribedChannel = subscribedChannel;
}
#Override
public void handleMessage(Message<?> message) throws MessagingException
{
synchronized (lock)
{
this.idChannelsMap.get(message.getHeaders().getCorrelationId()).send(message);
this.idChannelsMap.remove(message.getHeaders().getCorrelationId());
}
}
public void add(Object correlationId, MessageChannel messageChannel)
{
synchronized (lock)
{
this.idChannelsMap.put(correlationId, messageChannel);
}
}
public SubscribableChannel getSubscribedChannel()
{
return subscribedChannel;
}
}