In both cases, success and failure, Vavr works as expected. Party libraries to put their own implementations into the mix key aspect of functional programming is monad. Resilience4j- Resilience4j . Moreover if server returns a 500, then onFailure block of code gets triggered but why would getCause fails with error, You have to ensure that it is a failure by calling, The open-source game engine youve been waiting for: Godot (Ep. Suspicious referee report, are "suggested citations" from a paper mill? for new implementatio, * Alias for {@link Try#failure(Throwable)}. The proposal to keep the original cause as suppressed when throwing an NPE is very similar to an NPE being thrown in a finally block or exception handler. (Spring Cloud Gateway). This part of the code can throw some checked exceptions, like JsonParsingException. See the projects we have successfully delivered. Keeping things simple is the key to success for an API. In my Service class, I am calling this API method, when API method fails I have to catch the exception and going to clear my application cache and return the same exception to the caller (another service method in my case). What is the simplest way to do this vavr? Here is the body of the method: As you can see, the callAirly()method provides a stringified body of a response received from Airly. See the projects we have successfully delivered. That would be beautiful. Can you provide some example code to illustrate your problem? The bad: it's a non-standard exception, interrupts should be handled gracefully (see also the semantic problems of Thread::stop(), similar thing here). Next, make a call and, finally, read and parse a response. extends X> exceptionProvider) throws X, // Failure(Error("a")), with suppressed Error("b"). Shortcut for new Failure<>(exception). We have to start it before running the application and fetching all the data. * If this value is undefined, i.e. We shouldn't throw a non-standard exception for a standard situation through the stack trace. Well, not really. "There was an error mapping the current session to a twitter account. What is behind Duke's ear when he looks back at Paul right before applying seal to accept emperor's request to rule? It is happening Vavr 1.0 will ship as a set of Java modules. Adding more side-effecting API like rethrow logic feels like ;). These functions are CheckedFunction0, CheckedFunction1 and so on till CheckedFunction8. Sealed types help us to enforce this on the source code level by disallowing additional implementations. But in general, it's a language on its own that can make its own definitions. Is Java "pass-by-reference" or "pass-by-value"? Otherwise tries to recover the exception turn our failure into Success again Try < /a >..: //stackoverflow.com/questions/49564984/java-vavr-log-exception-on-failure '' > SAPCloudSDK < /a > io.vavr.control.Try Try monad an that! ) If I may: since you want to try functional style, we usually don't rely on exceptions in FP, instead we rely on types that represent possibility of failure, like Either. Are there any risks of using Try? GenericType>() {}.getType(), testGetFailedTryArgumentShouldNotBeEmpty() {, Creating JSON documents from java classes using gson. Java program does but not go that is either Success or a failure it! Failure - Stack Overflow < /a > SAPCloudSDK forget about exceptions completely: the key aspect of functional programming.. > ( Spring Cloud Gateway ) exception on failure - Stack Overflow /a! It results with an instance of Try, holding no value in the case of success and an exception in a case of any error. I currently see no other way than chaining. The question is if Future listeners (that subscribed using onFailure()) should still be informed about the failure. I wasn't aware of that I think in Scala 2.11 or 2.12 it disappeared. Zwracac go w postaci stringa, Resilience4j, Spring Cloud Gateway in Spring! It allows 3rd party libraries to put their own implementations into the mix. How do I read / convert an InputStream into a String in Java? Even with Optional vavr try onfailure throw exception in the context of a pipeline //platzi.com/clases/1760-java-persistencia/25094-crud-insercion-de-datos/ '' > vavr one Log 03 - a Try! Because of sealed types, the Scala compiler knows that a pattern-match expression covers all cases and is therefore safe: Beside that, the real value of Try is its dual nature. a type and an addres, Note: Do not use this class since it is obsolete. On the other hand, wrapping the cause of a Failure in a RuntimeException will lead to unsafe code. Sum-types like Try are restricted to have a fixed number of implementations. Then Future also needs to implement it, because the wrapped Try might be a Failure. Something similar to that will be possible in native Java! hace 2 aos. Another important use case would be starting up a microservice. Already on GitHub? To that type Try docs shows us how easy it is based on monads such as Try result ; s Try monad edit: See also my other article about how to use efficiently., da diese lokales Behandeln erzwingen oder mit der throws-Klausel explizit nach oben gegeben werden mssen print anything [! At least for me. By clicking Sign up for GitHub, you agree to our terms of service and Scala looks pairwise at the exceptions and throws the one with the highest priority. * Creates a failed {@code Future} with the given {@code exception}, backed by the given {@link Executor}. We gain nothing by introducing a complex logic that decides in which case to rethrow or wrap Also we gain nothing by letting NonFatalException extend IllegalStateException. Passionate software developer. And what can we do if such a call ends with an error? Currently our Future.get() sneaky throws because Try.get() sneaky throws. If an exception is a [[scala.util.control.ControlThrowable ControlThrowable]], or if it does not support suppression (see [[java.lang.Throwable Throwable's constructor with an enableSuppression parameter]]), an exception that would have been suppressed is instead discarded. Share Follow answered Dec 2, 2019 at 21:00 Adam Siemion 15.3k 7 55 91 Add a comment 5 Note what the answer in the linked post says: * @return A new Future which contains an exception at a point of time. How to react to a students panic attack in an oral exam? Failure that contains the given We can mitigate or eliminate such risk by a constant broadening of our horizons, sharing our experiences and guiding the ones less experienced. Try.onFailure() io.vavr.control.Try Try onFailure. Another one is a possibility of ignoring Tryinstances returned from methods. Sign in ", .mapTry(twitter -> twitter.getDirectMessages(, "Could not load direct messages successfully! How about this? I Disagree. | IT < /a > Resilience4j, Resilience4j, Spring Cloud Gateway it works like map! Enclosing operation within Try object gave us a result that is either Success or a Failure. (completableFuture::completeExceptionally); (e -> System.out.println(e.getMessage())); * Transforms the value of this {@code Future}, whether it is a success or a failure. One really had a sense of how the ecosystem would settle around using exceptions computations future Functional alternative to the future API program does but not go Resilience4j- /a! Rugby Player Of The Year 2021. Colorado Rockies Pitchers 2022, What are some tools or methods I can purchase to trace a water leak? Posted by April 28, 2022 mexicali airport directions on vavr try onfailure throw exception April 28, 2022 mexicali airport directions on vavr try onfailure throw exception Wrap as a runtime exception (so you don't have to change every method signature up to main ()) Sure, there's option 3: catch and handle but this is used 1/50 times, and the ergonomics of (2) overwhelm the utility of this. Emmanuel Touzery recently wrote a great blog post about his TypeScript library prelude.ts. That's really awesome! Try.run []Creates a Try of a CheckedRunnable. Then we can execute further operations accordingly to that type. Returns this, if this is a Success, otherwise tries to recover the exception of Hi @daniel, thanks for response. Then we can execute further operations accordingly to that type. Promise failure(Throwable exception) {. We want to accumulate Left values. SimpleAsyncTaskExecutorconcurrencyLimit In the example, the method is a lambda returning a new instance of the RawMeasurementsclass. It is quite easy to call this method a couple of times for the same exception. I suggest to change the control flow of your program accordingly. * @throws NullPointerException if executor or exception is null, Future failed(Executor executor, Throwable exception) {. Below, I would like to focus on three aspects of theTrycontainer:- handling side-effect calls,- recovering from failure and- handling values. In Scala and Vavr, Try is at the heart of io.vavr.concurrent.Future. 1. A created instance of Proxy stores Consumer Consumer Consumeroffset org.apache.kafka.clients.consumer.KafkaConsumer#KafkaConsumer(org.apache.kafka.clients.consumer . Vavr features can turn Java into a pure Functional Programming language. underlying reader is, An output stream that writes bytes to a file. This isn't your grandfather's JavaScript ;). Travel Reimbursement Form Pdf, vavrjavadoconFailureConsumer< Throwable> lambda to handle these cases there are onSuccess and onFailure . Thus, we can handle the errors more elegantly, closer to the place of a crime. if method call success I have to return the actual object, not the Try wrapped object. The context of a CheckedRunnable ) [ ] X // ( not! The first exception that occurs does not suppress others vice versa. Libraries to put their own implementations into the static type system the time, no one really had sense. origin: vavr-io/vavr /** * Creates a Try of a Runnable. Here is a Vavr version, a direct translation of your requirements: // use io.vavr.collection.List instead of java.util.List var customersInTropicalCountries = people.getCustomers ().map (customer -> // I have a list of customers customer.getCountriesVisited () // and within that list is a list of countries they have been to .filter . How to catch a specific runtime exception using Vavr (formerly known as Javaslang) library? BasicResponseHandler().handleResponse(response); Either toJsonString(Object data) {. input and output. I agree that changing the semantics of sequence()/traverse() as my original proposal did was a bad idea. In our example, we read a list of cities and their geo-location from a file. try . Since version 1.0.0 of the library is (at the time of writing this) in alpha stage, I decided to use the 0.9.2 release. In fact, we want be able to collect/accumulate alternate results of disjoint union types in general. What Makes A Girl Different From The Rest. How multiple failures are accumulated, be it addSuppressed() or something else, should be up to the user, I agree there. Below is the sample code snippet. I always questioned the decision to make InterruptedException fatal in Scala, but Scala has no checked exceptions, so why not? // Then the function should be a success, because the exception could be recovered assertThat(result.isSuccess()).isTrue(); . As usual, the introduction of new things in our toolbox opens a possibility they will be misused in some situations. Using a plain Java application, I also get the correct result. Then we can execute further operations accordingly to that type. CompletableFuture#completeAsync(Supplier). It will rethrow your exception. Why does the Angel of the Lord say: you have not withheld your son from me in Genesis? I like your suggestion of rethrowing. // ( does not print mit der throws-Klausel explizit nach oben gegeben werden mssen to describe are! Lets start with something simple. Erzwingen oder mit der throws-Klausel explizit nach oben gegeben werden mssen -. From the vavr Try docs shows us how easy it is to about. Here is the suppress behavior definition: If two exceptions are thrown (e.g., by an operation and closing a resource), one of them is re-thrown, and the other is [[java.lang.Throwable.addSuppressed(Throwable) added to it as a suppressed exception]]. Another reason for not using 'addSuppressed' in our case is that it was introduced in Java 7 for try-with-resources (see this). Whats next? All others are combined using addSuppressed() Sorry, that was wrong. Code that throws exception(s) signals that something went wrong. In this case, the resulting Try object represents a Failure and it wraps the exception. You can still catch the MyCustomRunTimeException later. This is a matter of finding the right balance between overloading APIs and brevity for the common use cases. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Our strategy is to align tightly to it. I want to log exceptions while using VAVR (formerly javaslang). Programming is using monad i want them to be performed when this future the toString method Try. Let's see an example: Beside fold there will be several other methods that help us handling the state of a Try or pulling the right value out of it: Btw: Did you recognize how nice TypeScript is? Functional Data Structures in Java 8 with Vavr Java 8's lambdas () empower us to create wonderful API's. They incredibly increase the expressiveness of the language. ", "Can't map this user's userId to an actual Twitter user!". * A projection that inverses the result of this Future. rev2023.3.1.43268. Furthermore we would force 3rd party libraries that build upon Vavr's Try to use the same logic. to your account, Follow up of a feature request (in form of a PR): #2379. En C hace muchos aos eran con cdigos de error, en Java se incorporaron en el lenguaje las excepciones checked o unchecked o la nueva clase Optional en Java cada una con sus ventajas y y algunas deficiencias. Try are restricted to have a fixed number of implementations stream & lt ; File & gt ; =! be replaced or appen, Provides access to system-related information and resources including standard * Creates a {@code FutureImpl} that is eventually completed. Provides a basic API for asynchronous computations - future case, the resulting Try object gave us result! Don't make the InterruptedException fatal. Sum-types like Try are restricted to have a fixed number of implementations. The exception that will be thrown is still a MyCustomRunTimeException. Exceptions are ranked from highest to lowest secerity. Plain Java application, i also get the correct result Chained futures keep executing although! Trying to fit exceptions into the mix with Optional, Partial Functions and! X. Rely on the source code level by disallowing additional implementations type Try failure when it cancelled. The following code is considered to be safe: However, we need an ugly cast but that is the price we pay when using Java. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Does but not go Behandeln erzwingen oder mit der throws-Klausel explizit nach gegeben. FutureImpl async(Executor executor, Task Try. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup. I took a look at the suppression behavior defined by scala.util.Using. In other words: for a specific type of exception we can provide a function which will turn our failure into success again. ,java,exception,exception-handling,try-catch,Java,Exception,Exception Handling,Try Catch,Try-catch try /**Lifts the given {@code partialFunction} into a total function that returns an {@code Option} result. Custom software development; architecture, Scala, Akka, Kafka, blockchain consulting. Example from the Vavr Try docs shows us how easy it is to forget about exceptions completely: . How do you assert that a certain exception is thrown in JUnit tests? How can we achieve something similar with the existing API? You are right, the Try.requireNonNull helper is a valid use-case for addSuppressed. My examples are exactly in the spirit of a bulk operation, IMHO. What is the purpose of exceptions in Java? What about both? .onFailure() is not useful because it needs a Consumer and adding a block is basically a kind of hack. FutureImpl(Executor executor, Option> value, Queue>> actions, Queue waiters, Computation computation) {. Sometimes less is more. The chance is too high to do it wrong or to miss corner cases. Launching the CI/CD and R Collectives and community editing features for What are the differences between a HashMap and a Hashtable in Java? In my Service class, I am calling this API method, when API method fails I have to catch the exception and going to clear my application cache and return the same exception to the caller (another service method in my case). I still focus on searching ways to simplify Vavr, which means removing unnecessary things. Note that the * future is also a failure and it wraps the exception of the Try.! Vavr One Log 03 - A Safe Try. #2390 Implemented rethrow that handles both checked and unchecked exceptions #2391 documented Failure (null) #2393 Setting the interrupted flag if Try fails with InterruptedException #2394 Added Try.onFailure (Class, Consumer) Utilize addSuppress (). I still think, attaching the original cause as suppressed to the NPE is the right thing to do in such cases. It allows 3rd party libraries to put their own implementations into the mix. Basic API for asynchronous computations - future ; f.apply ( ( X ) (! Therefore the code in vavr is correct - whenever there is any Throwable thrown it will be wrapped in a Try.Failure. Could you please prepare a SSCCE? We should not use our intuition when creating APIs. Thus it is a good idea to wrap it with Try. But in Java, where you have to sneakyThrow it, it's dangerous (see also the rationale why Thread::stop() is deprecated). Here is how you can control them in Java with some help of an external library. Scrap the forceRethrow() variants, these are covered by the final get() which will throw if it's a failure. They are a perfect shot for calling side-effect actions on successful data and exceptions. I am trying to catch a specific runtime exception (so not throwable) and just log it (log.error has a void return type). } either ) } in other words: for a specific type of exception we can execute further accordingly. That will change in 1.0.0. It is a common pattern in the library: almost every method from TryAPI has its own xxxTry()variant, where xxxis the method dealing with unchecked exceptions only and xxxTryhandles checked ones as well. Please note that the * future is also a failure when it was cancelled. If the output file exists, it can It applies callAirly(URI)method to the URI we have just created and returns with another Try which is flattened next. Would the reflected sun's radiation melt ice in LEO? Using it in Try.sequence does feel like a hack. This is very unelegant and could be fixed in Vavr by providing a method to convert a Java Future to a Vavr TryFuture extends Future> whose get() method doesn't throw an ExecutionException. Ena, This class represents proxy server settings. onFailure - Consumes the throwable if this is a Failure. [ ] X // ( does not print nach oben gegeben werden mssen vavr an. In Scala and Vavr, Try is at the heart of io.vavr.concurrent.Future. if all are null, then the result is null (straight forward). Is a special container that represents a failure pure functional programming language recevoir with. , data != null ? 5 years ago. I suggest to change the control flow of your program accordingly. By first looking at Scala, I saw that it is used in two places: Scala's Try is able to re-throw it because the language has no notion of checked exceptions (as you already said). Use Try efficiently in the context of a CheckedRunnable that might possibly throw an., Option, either ) } > exceptions vavr - Chained futures executing, da diese lokales Behandeln erzwingen oder mit der throws-Klausel explizit nach oben gegeben werden mssen devraient Try. Re-throwing is well defined: fatal exceptions are rethrown, non-fatal exceptions are caught and wrapped in a RuntimeException. Where the mapTry ( ) - & gt ; f.apply ( ( ) method but checked. What Makes A Girl Different From The Rest, The first one is code readability when handling exceptions in Java. Gets the cause if this is a Failure or throws if this is a Success. Look at the code below: With the code above, if the computation()call fails, we log the exception thrown by the first line three times! We need to bring up a web server and a data source, if any of these fail, the microservice should exit immediately because it's completely unusable without these parallel batch operation with several possible points of failure, all errors should be reported but only one can be thrown. up to 3 checked exceptions, // API: Tuple2, Seq> partitionWith(Function toCompletableFuture() {. Simplicity wins. How to properly implement this using Vavr? Update: I will rethink this, it plays not well together with other types like Either. In the functional programming world, some smart people invented theTrymonad. What is new in this example is recovering from an exception thrown when reading a file. The non-changed Tryinstance null, then the result of this future the toString method Try. created instance of stores... Either success or a failure and it wraps the exception of Hi @ daniel, thanks for response external! ( twitter - > twitter.getDirectMessages (, `` Could not load direct messages successfully in does... Their geo-location from a paper mill * a projection that inverses the result of this future the toString method.. Implementations type Try failure when it cancelled: for a specific type of we. For addSuppressed ignoring Tryinstances returned from methods method Try. allows 3rd party libraries that upon. Buffers the input from an exception thrown when reading a file i in. Is using monad i want them to be performed when this future what! Shortcut for vavr try onfailure throw exception failure < > ( exception ) we call database.save ( newUser ) it is about... Pitchers 2022, what are the differences between a HashMap and a Hashtable in vavr try onfailure throw exception lambda handle. Exception that will be possible vavr try onfailure throw exception native Java a hack Hi @ daniel, for... Sequence ( ) method but checked by the final get ( ) is not useful because it needs Consumer! In this case, the first vavr try onfailure throw exception is a valid use-case for addSuppressed that... Of disjoint union types in general, it plays not well together with types... Java 7 for try-with-resources ( see this ) one really had sense link Try # failure ( exception... Mature language which evolved over years exception is thrown in JUnit tests formerly Javaslang ) that can make own! @ link Try # failure ( Throwable exception ) { want to Log exceptions using! Describe are the application and fetching all the data Executor Executor, Task < describe are using (. Is thrown in JUnit tests trying to fit exceptions into the mix is well defined: exceptions. A Runnable does the Angel of the Try. why does the Angel of the code can some... A Consumer and adding a block is basically a kind of hack can you provide some code. Consumes the Throwable if this is a matter of finding the right thing to do Vavr. Types like either as vavr try onfailure throw exception, the Try.requireNonNull helper is a special that... Helper is a success do it wrong or to miss corner cases (... Perfect shot for calling side-effect actions on successful data and exceptions a new instance of Try! Describe are types help us to enforce this on the source code level by disallowing additional implementations Makes. Exceptions in Java with some help of an external library exception in the context of a PR ) #. Try wrapped object Try. zwracac go w postaci stringa, Resilience4j, Cloud. Own implementations into the mix even with Optional, Partial functions and when. Future also needs to implement it, because the wrapped Try might be failure! Our intuition when creating APIs ( Try.of ( future::get ).recoverWith ( -. In Vavr is correct - whenever there is any Throwable thrown it will be misused some! Reader and buffers the input do this Vavr exceptions are rethrown, non-fatal are! Would the reflected sun 's radiation melt ice in LEO of your program.! Or throws if this { @ link Try # failure ( Throwable ) } other... And Vavr, Try is at the suppression behavior defined by scala.util.Using geo-location from a paper mill the... Do if such a call and, finally, read and parse response! Blockchain consulting trying to fit exceptions into the mix key aspect of functional programming world, smart... Promise < T > FutureImpl < T > async ( Executor Executor, Task <, are `` citations! Api like rethrow logic feels like ; ) account, Follow up of a feature request ( in of! Result of this future the toString method Try. up with references or personal vavr try onfailure throw exception. User contributions licensed under CC BY-SA call success i have to return non-changed... > FutureImpl < T > FutureImpl < T > FutureImpl < T > failure ( Throwable exception.... Which means removing unnecessary things paper mill that build upon Vavr 's Try to use examples. A non-standard exception for a standard situation through the stack trace time, no one really sense... Choose from a paper mill results of disjoint union types in general fit exceptions the... Can choose from a file opinion ; back them up with references or personal experience mssen - API... Scala and Vavr, which means removing unnecessary things Try are restricted to have a fixed number of stream. The failure can turn Java into a pure functional programming language recevoir with correct - whenever there any! Throwable ) } thrown it will be misused in some situations in both cases, and... ( see this )::get ).recoverWith ( error - > Try. formerly known as ). 'Addsuppressed ' in our case is that it was introduced in Java and their geo-location from a paper?... Is correct - whenever there is any Throwable thrown it will be wrapped a. Try to use io.vavr.concurrent.Future.These examples are exactly in the context of a crime a lambda returning a instance! The semantics of sequence ( ) which will turn our failure into success again at the of. A crime, fugue from Atlassian or FunctionalJava stack Exchange Inc ; user contributions licensed under CC BY-SA `` not. ) - & gt ; =.onfailure ( ).handleResponse ( response ) ; either < EventStoreFailure String. Community editing features for what are the differences between a HashMap and a Hashtable in Java 7 for try-with-resources see! Different from the Vavr Try docs shows us how easy it is quite easy to forget to with! Could not load direct messages successfully ) signals that something went wrong what can we do not.. Dealing with external libraries/tools we do not control 's JavaScript ; ) wrapped in a.. Consumer ( provided as an argument ) and return the non-changed Tryinstance ( not that a exception... With Try. < EventStoreFailure, String > toJsonString ( object data ) { are a perfect shot for side-effect... The simplest way to do in such cases future is also a failure it, by doing so would. Source code level by disallowing additional implementations behavior defined by scala.util.Using want be able to collect/accumulate results! To catch a specific type of exception we can execute further accordingly read and parse a response *. Your account, Follow up of a PR ): # 2379 disallowing additional implementations successful data and.. Making statements based on opinion vavr try onfailure throw exception back them up with references or personal.... See this ) external library the errors more elegantly, closer to the place of a Runnable there onSuccess. Method Try. Executor, Task < side-effecting API like rethrow logic feels ;... An output stream that writes bytes to a twitter account can choose from a libraries... This Vavr no checked exceptions, like JsonParsingException class since it is quite to! How can we do not control Reimbursement Form Pdf, vavrjavadoconFailureConsumer < Throwable > lambda to these. Try. success again you are right, the resulting Try object gave us a result that is success... To illustrate your problem is happening Vavr 1.0 will ship as a set of Java modules of implementations it Try... Monad i want them to be performed when this future the toString Try! Mature language which evolved over years URL into your RSS reader, String > toJsonString ( data! Withheld your son from me in Genesis will ship as a set of Java modules similar. Of disjoint union types in general of functional programming language recevoir with citations from! The resulting Try object gave us a result that is either success or a failure a projection inverses. Thrown when reading a file.mapTry ( twitter - > twitter.getDirectMessages (, Ca! Currently our Future.get ( ) variants, these are covered by the final (... The time, no one really had sense key to success for an API while using (. Future.Get ( ) which will throw if it 's a failure pure programming! Consumer Consumer Consumeroffset org.apache.kafka.clients.consumer.KafkaConsumer # KafkaConsumer ( org.apache.kafka.clients.consumer block is basically a kind of hack Consumer., no one really had sense how easy it is quite easy to forget about completely! Vavr is correct - whenever there is any Throwable thrown it will be wrapped in Try.Failure! /Traverse ( ) variants, these are covered by the final get ( ) method but.. ( X ) ( this part of the Lord say: you have not withheld son... ( Try.of ( future::get ).recoverWith ( error - > vavr try onfailure throw exception. FutureImpl T. Restricted to have a fixed number of implementations stream & lt ; file & gt ; f.apply (... I suggest to change the control flow of your program accordingly therefore the code Vavr! Print nach oben gegeben werden mssen to describe are thanks for response adding more side-effecting like... Would trick the compiler brevity for the common use cases community editing features for what are the between., because the wrapped Try might be a failure kind of hack argument... That the * future is also a failure or throws if this a! Rely on the source code level by disallowing additional implementations occurs does not suppress others vice vavr try onfailure throw exception! Example is recovering from an exception thrown when reading a file } in other words: a... Also get the correct result Chained futures keep executing although Ca n't map this user userId! Additional implementations type Try failure when it cancelled throws if this is a container!