Stub | Flexible Stub wrapper for PHPUnit 's Mock Builder | Unit Testing library

Like you noticed already, you can only check interactions on a mocked object type, i.e. mock, stub or spy. The latter, a spy, is what you need in this case, i.e. something like:

do some query work with Spark SQL

You wouldn't use a ForEachWriter for that

[Solved] Work for me Install below

You can check if the return address is in the executable or the library, and then call either the "real" function or do your stub code, like this:

Looks like all is eplained in your exception:

Unsatisfied dependency expressed through field 'userDeatilService';

nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userDeatilService': Unsatisfied dependency expressed through field 'userRepo';

nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'usersRepo' defined in com.barsamin.ws.repo.UsersRepo defined in @EnableJpaRepositories declared on BarsaminWebApplication:

Invocation of init method failed; nested exception is java.lang.IllegalArgumentException:

Failed to create query for method public abstract java.util.Optional com.barsamin.ws.repo.UsersRepo.findByUserName(java.lang.String)!

No property userName found for type Users! Did you mean 'username'?

When the method reference is called from the class but it is an instance method : it needs an instance to work.

That's why Function addingMoney = Money::addMoney; works

• like the Supplier, it returns a Money instance (2nd generic type)
• as it is an instance method, it needs a Money instance as input (1st generic type)

That's why Consumer returnMoney = Money::addMoney; works

• it is like half of the Function, it takes the instance as input
• but you tell that you don't care of the result

Then lambda equivalent may help you

Can I try to read if it no data available?

Yep, and it's going to be case more often than not. Read() will do nothing until data is available, and only then put its passed tag into the completion queue. (see below for details)

Is it blocking call?

Nope. Read() and Write() return immediately. However, you can only have one of each in flight at any given moment. If you try to send a second one before the previous has completed, it (the second one) will fail.

What is the proper way to async reading?

Each time a Read() is done, start a new one. For that, you need to be able to tell when a Read() is done. This is where tags come in!

When you call Read(&msg, tag), or Write(request, tag),you are telling grpc to put tag in the completion queue associated with that responder once that operation has completed. grpc doesn't care what the tag is, it just hands it off.

So the general strategy you will want to go for is:

• As soon as you are ready to start receiving messages:
  • call responder->Read() once with some tag that you will recognize as a "read done".
• Whenever cq_.Next() gives you back that tag, and ok == true:
  • consume the message
  • Queue up a new responder->Read() with that same tag.

Obviously, you'll also want to do something similar for your calls to Write().

But since you still want to be able to lookup the handler instance from a given tag, you'll need a way to pack a reference to the handler as well as information about which operation is being finished in a single tag.

Lookup the handler instance from a given tag? Why?

The true raison d'être of completion queues is unfortunately not evident from the examples. They allow multiple asynchronous rpcs to share the same thread. Unless your application only ever makes a single rpc call, the handling thread should not be associated with a specific responder. Instead, that thread should be a general-purpose worker that dispatches events to the correct handler based on the content of the tag.

The official examples tend to do that by using pointer to the handler object as the tag. That works when there's a specific sequence of events to expect since you can easily predict what a handler is reacting to. You often can't do that with async bidirectional streams, since any given completion event could be a Read() or a Write() finishing.

Here's a general outline of what I personally consider to be a clean way to go about all that:

check this line in Cart#toString(), and if removing it helps:

output += Arrays.toString(itemsList);

Do console.log(req.body) first, if you can't read the data, check 3 things.

1. Check if server router HTTP method is one of post, put, delete
2. Check if browser side HTTP calls right method and argument ex>axios.post(url, data, config)
3. Check if body parser is attached in same context. For example, if you did app.use(bodyParser()) , all sub routes should be attached into app to refer req.body

If this check list doesn't work for you, please share client-side code and server-siderouter code for details.