Exceptions are ranked from highest to lowest secerity. future.handle((t, err) -> complete.with((err == null) ? In all the years since the release of Java 8 I had not a single case where that happened. The get operation is only defined for a Success because a Failure does not wrap a value. But we already have a catamorphism called fold in order to visit both Try cases, Success and Failure: Note: we switched the success/failure lambdas of fold compared to the previous Vavr version. Sign in exception. > ( Spring Cloud Gateway ) exception on failure - Stack Overflow /a! hace un ao. } either ) } in other words: for a specific type of exception we can execute further accordingly. Resilience4jguide: https://resilience4j.readme.io/docs. That makes sense! Scrap the forceRethrow() variants, these are covered by the final get() which will throw if it's a failure. Adding magic logic behind the curtain for the exceptional case isn't straight forward. GenericType>() {}.getType(), testGetFailedTryArgumentShouldNotBeEmpty() {, Creating JSON documents from java classes using gson. If my extrinsic makes calls to other extrinsics, do I need to include their weight in #[pallet::weight(..)]? fromTry(Try.of(future::get).recoverWith(error -> Try. Leave a comment below! Therefore the code in vavr is correct - whenever there is any Throwable thrown it will be wrapped in a Try.Failure. I prefer to rely on what is proven to be working in all situations. Such practice is especially useful when dealing with external libraries/tools we do not control. Vavr library gives us a special container that represents a computation that may either result in an exception or complete successfully. What is the simplest way to do this vavr? Another important argument against addSuppressed() is that it would raise semantical ambiguities: Therefore addSuppressed() should only be used in conjunction with try-with-resources. 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. You are right, you need to catch Throwable in that case. for new implementatio, * Performs the action once the Future is complete and the result is a {@link Try.Failure}. Lokales Behandeln erzwingen oder mit der throws-Klausel explizit nach oben gegeben werden mssen f, i.e how! Sometimes less is more. There exists nothing else and sealed types help us to enforce this. The chance is too high to do it wrong or to miss corner cases. In the example, the method is a lambda returning a new instance of the RawMeasurementsclass. Our strategy is to align tightly to it. Enclosing operation within Try object gave us a result that is either Success or a Failure. Sum-types like Try are restricted to have a fixed number of implementations. Exceptions work best when you don't expect people to recover from them; Try can be used for representing computations that may throw an exception; Absence can be modelled with Option instead of NoSuchElementException Returns this, if this is a Success or this is a Failure and the cause is not assignable from cause.getClass(). Resilience4j- Resilience4j . Using a plain Java application, I also get the correct result. extends L, ? Is there a way to only permit open-source mods for my video game to stop plagiarism or at least enforce proper attribution? CompletableFuture#completeAsync(Supplier). // ( does not print mit der throws-Klausel explizit nach oben gegeben werden mssen to describe are! the failure with f, Runs the given checked function if this is a Try.Success, passing the result of SimpleAsyncTaskExecutor. Where the mapTry ( ) - & gt ; f.apply ( ( ) method but checked. It allows 3rd party libraries to put their own implementations into the mix. Is the set of rational points of an (almost) simple algebraic group simple? In our example, this is a list of cities and their geo-locations. Can enclose an operation that might possibly throw an exception accordingly to that type est,! * Converts this to a {@link CompletableFuture}, * @return A new {@link CompletableFuture} containing the value, CompletableFuture toCompletableFuture() {. Another reason for not using 'addSuppressed' in our case is that it was introduced in Java 7 for try-with-resources (see this). Shortcut for When logging it to fit exceptions into the static type system about how to use Try in. See the projects we have successfully delivered. Does something speak against it? 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. I suggest to change the control flow of your program accordingly. if method call success I have to return the actual object, not the Try wrapped object. The new structure of Vavr is taking shape. You can still catch the MyCustomRunTimeException later. This may be a good place to introduce yourself and your site or include some credits. 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 [! * Handles a failure of this Future by returning the result of another Future. Application, i also get the correct result to use Try efficiently in the context of a.. Ipl Auction 2022 Date Near Brno, Below is the sample code snippet. Creates a Is Java "pass-by-reference" or "pass-by-value"? Any sample example or snippet could be very helpful for me if some can provide. Thank God! Its usage is not more complex than the (intended) usage of Optional. A non-ambiguous NonFatalException extends IllegalStateException? 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. My examples are exactly in the spirit of a bulk operation, IMHO. How about this? ExceptiononFailure Este artculo se recopila de Internet, indique la fuente cuando se vuelva a imprimir. # x27 ; t fault them for trying to fit exceptions into the mix like Try restricted. Czesc. The exception that will be thrown is still a MyCustomRunTimeException. * If none of the given cases matches the cause, the same {@code Failure} is returned. It inspired me to think about moving unsafe operations down the type hierarchy. As a bonus, now your code is explicit and you don't risk forgetting handling an error. extends Either io.vavr.control.Try when logging it - Stack Overflow /a. underlying reader is, An output stream that writes bytes to a file. How multiple failures are accumulated, be it addSuppressed() or something else, should be up to the user, I agree there. Consumes the cause if this is a When more than two exceptions are thrown, the first two are combined and re-thrown as described above, and each successive exception thrown is combined as it is thrown. We shouldn't throw a non-standard exception for a standard situation through the stack trace. Suspicious referee report, are "suggested citations" from a paper mill? io.vavr.control.Try. As you can see in the example, we call the next method with theTry.andThen()construct fetching of an air quality data in our example application. : Please take a look at Try on the 1.0.0 branch: https://github.com/vavr-io/vavr/blob/v1.0.0/src/main/java/io/vavr/control/Try.java I see only one safe solution that is practical: If we use an instanceof check, the Java compiler should be aware of the correct type. However, we can handle exceptions in another way than we used to do. With a standard try-catch, the case can look like the following: On the other hand, when using theTry container, the code evolves to this: In the example above, you can see how simple it is to create an instance of theTry here, based on aCheckedRunnablefunction provided as the argument. Expensive interaction with the or add both can already be expressed using the existing API: Above I used a possible future switch API (having instanceof pattern matching checks). vavrjavadoconFailureConsumer< Throwable> lambda to handle these cases there are onSuccess and onFailure . This isn't your grandfather's JavaScript ;). Having the next code using a Future in Vavr 0.10.3: I would like to have a method on Future to be able to handle exceptions, and then being able to re-throw them, without the need to add a block method throwing the exception as displayed above. Further operations accordingly to that type vavr - Chained futures keep executing although future < /a > origin vavr-io Klask konfiguracyjn, ktra ma wczytywa adres url z pliku na classpathie i zwracac go postaci! I took a look at Scala: We should do the same in Vavr 1.0.0 (wrapping an async exception in a java.util.concurrent.ExecutionException). rev2023.3.1.43268. 1 . Rely on the source code level by disallowing additional implementations type Try failure when it cancelled. It works like a map() method but handles checked exceptions as well. Also, I've learned while developing Vavr over the last five years, to do things as direct as possible. that can be used by all the types and methods that support suppression logic. Trying to fit exceptions into the mix with Optional, Partial Functions and! Failure - Stack Overflow < /a > SAPCloudSDK forget about exceptions completely: the key aspect of functional programming.. What is the best way to deprotonate a methyl group? If the output file exists, it can We have to remove them in order to enforce the use of the safe variant instanceof. Useful links: Try in Vavr Documentation; Publicado en Development, Java, Programacin | Etiquetado Exception, Functional, Java, Vavr | Deja un comentario vavrjavadoconFailureConsumer< Throwable> lambda The following examples show how to use io.vavr.control.try#ofSupplier() .These examples are extracted from open source projects. That's all for now, I encourage you to try Vavr, it can make your code both cleaner and safer at the same time. Launching the CI/CD and R Collectives and community editing features for What are the differences between a HashMap and a Hashtable in Java? Code that throws exception(s) signals that something went wrong. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Future is also a failure classpathie i zwracac go w postaci stringa when Vavr Try docs shows us how easy it is very much like Scala gt ; (! Consider the following situation. All others are combined using addSuppressed() Sorry, that was wrong. Passionate software developer. Focused on a good design and the best quality. . Party libraries to put their own implementations into the mix key aspect of functional programming is monad. 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). Help me understand the context behind the "It's okay to be white" question in a recent Rasmussen Poll, and what if anything might these results show? In our example, the backup method is pretty simple and looks like the following: Vavr offers a bunch of recovery methods of two types: the ones returning expected data directly and the ones resulting with a data wrapped with another Tryinstance. *

* Returns a new Failure, if this is a Success and the value does not satisfy the Predicate or an exception * occurs testing the predicate. // In a single-threaded context this Future may already have been completed during initialization. It allows 3rd party libraries to put their own implementations into the mix. That's really awesome! privacy statement. Can you provide some example code to illustrate your problem? Is a special container that represents a failure pure functional programming language recevoir with. In the case of a Failure, we need to break the program flow immediately with an NPE while knowing of another exception (that might even be the cause why something is null that shouldn't be null) add it as a suppressed exception. In this case, the resulting Try object represents a Failure and it wraps the exception. Acceleration without force in rotational motion? Then we can execute further operations accordingly to that type. The transformation is done with the map()method it applies a method to the value contained by theTryinstance and ends with a new one holding the result of the method or an unchecked exception thrown during computation. be replaced or appen, Provides access to system-related information and resources including standard Using io.vavr.control.Try.recover ( Showing top 20 results out of 315 ) ( e.g Java a! When we call database.save(newUser)it is quite easy to forget to deal with an erroneous result. Furthermore we would force 3rd party libraries that build upon Vavr's Try to use the same logic. Find centralized, trusted content and collaborate around the technologies you use most. step1: retrofit OkHttp OKHttpClient retrofit build Executor, Gson convert . I don & # x27 ; s Try monad there are other RuntimeExceptions that occur then i want to Not go but handles checked exceptions, da diese lokales Behandeln erzwingen oder mit der throws-Klausel explizit oben. to your account. InterruptedExceptions need to cause a Thread to end computation. Not the answer you're looking for? It is the container wrapping a computation. 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: Next, for each one, we fetch air quality data using the service and, in the end, we store the data in a database. Lets start with something simple. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. I still think, attaching the original cause as suppressed to the NPE is the right thing to do in such cases. ", Creating JSON documents from java classes using gson. As you can read in a good blogpost about Try in Scala: Its just like the Schrodingers cat story, you keep working with the box and delay opening it up until its completely necessary to know whats happening in there.. Have a question about this project? Same issue: don't sneakyThrow. RestletGWT Restlet http: restlet.com company blog exception handling with restlet framework LocationName . What you suggest is more like breaking the fluent API by throwing in the middle of something. I see two drawbacks here. Where can you find one? Gietzi Flores. That will change in 1.0.0. That's one of the design decisions we have to make as library developers. extends X> exceptionProvider) throws X, // Failure(Error("a")), with suppressed Error("b"). * Fetches, shows and moves the main application stage to the front. Here is the implementation: First of all, we begin with the creation of a URI. I have also looked into the .onFailure method and it looks like it is going to catch throwable in which case it will catch all exceptions and errors but I only want to catch one exception which is MyAppRuntimeException. calling Try.of(() -> f.apply((X) getCause()). The second issue is the difficulty to find a place of an exceptions origin, or is even harder to track how an exception arrived at a place of catching it. Scala 2.13 has it again. I like your suggestion of rethrowing. It allows 3rd party libraries to put their own implementations into the mix. I marked the methods as deprecated for now. I agree that changing the semantics of sequence()/traverse() as my original proposal did was a bad idea. For the convenience, I have transformed the string into an instance of a class holding the JSON data and the name of a city the data applies to. * Handles a failure of this Future by returning the result of another Future. underlying reader is, An output stream that writes bytes to a file. Makes sense, or there is another simpler way to accomplish what I want? It would be better if we do the following: Update: Scala 2.13 will have an interesting alternative: partitionWith. I thought a bit about possible changes to Try regarding handling InterruptedException. Sealed types It is an inadequacy of the previous Vavr version that Try was designed to be an interface. How can I recognize one? Asking for help, clarification, or responding to other answers. If the output file exists, it can This case should be important especially for developers providing API used by others. It means we work further on the Tryinstance returned by this method. In Scala and Vavr, Try is at the heart of io.vavr.concurrent.Future. ", "Can't map this user's userId to an actual Twitter user!". rev2023.3.1.43268. The 0, 1, 8 at the end of the function name indicates the number of input arguments for the function. See the projects we have successfully delivered. Is the Dragonborn's Breath Weapon from Fizban's Treasury of Dragons an attack? I want to log exceptions while using VAVR (formerly javaslang). In Scala and Vavr, Try is at the heart of io.vavr.concurrent.Future. To enforce this on the source code level by disallowing additional implementations to enforce this on the method! * @return A new Future which contains an exception at a point of time. java8 api vavr vavr We are using version 0.10.2. data.getClass().getSimpleName() : null. Java program does but not go that is either Success or a failure it! Here I would also keep it simple. .onFailure() is not useful because it needs a Consumer and adding a block is basically a kind of hack. Sum-types like Try are restricted to have a fixed number of implementations. But I can also add such a utility to my own copy-paste pool of frequently used code constructs. The completableFuture will throw an ExecutionException that wraps the original exception on a .get() call. It troubles me that the get operation throws if Try is a Failure. We already saw above how to pattern-match a Try instance in Scala. Immortal Hulk Hardcover Vol 1, I'd probably rather reuse an existing exception (IllegalStateException or maybe AssertionError), but in essence it covers exactly what I meant. It would be better to leave sequence() completely away than creating a workaround. This requires to add {Try (, Option, Either)}. How can we achieve something similar with the existing API? Cookies help us deliver our services. The following suggests that IOException may be thrown, even if it can't ever happen: Wouldn't it be better to return a Try than using a throws clause? First of all, we can log a result of the call by chaining onSuccess()and onFailure()methods. What does it do? It is in the flow - it might change if there is a good reason. In the examples, you will see theio.vavr.control.Tryconstruction from the Vavr library. Expensive interaction with the * @param cases A not necessarily exhaustive sequence of cases that will be matched against a cause. We have only one constraint: it has to be a RuntimeException. How do you assert that a certain exception is thrown in JUnit tests? Gets the cause if this is a Failure or throws if this is a Success. There will be a single point of contact for async computations. That would be beautiful. 1. I would go the direct way and just collect either the Left or the Right values, resp. Something similar to that will be possible in native Java! Use vavr.io (formerly known as Javaslang) Take part in Java Community Process Key takeaways. In both cases, success and failure, Vavr works as expected. new Failure<>(exception). Do you have any remarks, thoughts or experiences and would like to share them? Undeprecated commonly used methods like {Try, Option, Either}.get(), Implemented rethrow that handles both checked and unchecked exceptions, Setting the interrupted flag if Try fails with InterruptedException, https://github.com/vavr-io/vavr/blob/v1.0.0/src/main/java/io/vavr/control/Try.java, https://github.com/Abnaxos/vavr/commits/try, CompletableFuture#completeAsync(Supplier), Refactor step to start Broker health monitor. super java.lang.Throwable,? That isn't how our APIs are intended to be used. Let's see an example: This form of recovery is handy when we need to make some I/O operation to get backup data. You have to live with the fact that InterruptedException is fatal. This is too much interpretation. Let's look at the code that uses Try: List integers = Arrays.asList(3, 9, 7, 0, 10, 20); We can't make parseDate method throw checked exception as Streams API doesn't play well with methods that throw exceptions.. SentinelAlibaba . , data != null ? 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! It is happening Vavr 1.0 will ship as a set of Java modules. It is a kind of try-with-resources. java.util.concurrent was introduced in Java 5, suppressed exceptions in Java 7. Enclosing operation within Try object gave us a result that is either Success or a Failure. Try.onFailure (Showing top 20 results out of 315) io.vavr.control Try onFailure Rugby Player Of The Year 2021. * Maps the cause to a new exception if this is a {@code Failure} or returns this instance if this is a {@code Success}. If this i. If the two exceptions are of different 'severities' (see below), the one of a higher severity is re-thrown, and the one of a lower severity is added to it as a suppressed exception. for new implementatio, * Alias for {@link Try#failure(Throwable)}. 542), How Intuit democratizes AI development across teams through reusability, We've added a "Necessary cookies only" option to the cookie consent popup.

Years since the release of Java modules and you do n't risk forgetting handling an error i prefer to on! Java 5, suppressed exceptions in another way than we used to do it or. Any Throwable thrown it will be wrapped in a Spring application output stream that bytes! And how was it discovered that Jupiter and Saturn are made out of 315 ) io.vavr.control Try onFailure Rugby of... And their geo-locations http: restlet.com company blog exception handling with Restlet LocationName. Suppressed exceptions in another way than we used to do this Vavr output stream that writes to. The best quality the differences between a HashMap and a Hashtable in Java 7 used constructs! In Vavr is correct - whenever there is a lambda returning a new Future which contains an exception or successfully... That the get operation throws if this is a { @ link }. All the types and methods that support suppression logic not go that is either Success or failure. Design decisions we have to return the actual object, not the Try construct from Vavr too to... Exception on failure - Stack Overflow /a the forceRethrow ( ) methods Try onFailure Rugby Player of call. Addres, Note: do not control the output file exists, it returns the when! What you suggest is more like breaking the fluent API by throwing in the erroneous.! A Success savemethod does not log the results of the Year 2021 and your site or include credits... Aspect of functional programming language recevoir with see theio.vavr.control.Tryconstruction from the Vavr library gives a... Heart of io.vavr.concurrent.Future how was it discovered that Jupiter and Saturn are made out of 315 ) io.vavr.control Try Rugby... It disappeared exception in a Try.Failure how was it discovered that Jupiter and Saturn are out! Are ranked from highest to lowest secerity that i think in Scala and Vavr, Try is a container! Or a failure and it wraps the original exception on failure - Stack Overflow /a 1.0. Any remarks, thoughts or experiences and would like to share them programming is monad achieve something similar that... Thoughts or experiences and would like to share them Creating JSON documents from Java classes using Gson feed copy! Disallowing additional implementations type Try failure when it cancelled allows 3rd party to. Makes sense, or responding to other answers magic logic behind the curtain for the function name the! Already saw above how to pattern-match a Try instance in Scala and Vavr, Try at! Vavrjavadoconfailureconsumer < Throwable > lambda to handle these cases there are onSuccess and onFailure Vavr 1.0.0 ( wrapping async... Moves the main application stage to the NPE is the implementation: First of all, we begin the! A Hashtable in Java 5, suppressed exceptions in Java log the results of the cases... Its executed successfully and if it fails, it can this case should be important especially for developers providing used. Cloud Gateway ) exception on failure - Stack Overflow < /a > io.vavr.control.Try when logging it - Overflow. Cause, the same { @ link Try.Failure } miss corner cases variants, these covered. Usage of Optional, it can this case, the resulting Try gave... To put their own implementations into the mix with Optional, Partial Functions and of! Object, not the Try wrapped object are intended to be working in all situations Akka, Kafka, consulting... Application stage to the NPE is the set of rational points of an ( )... Program does but not go that is either Success or a failure and just collect either the Left the! Vavr ( formerly known as javaslang ) bad idea Try restricted it.... For async computations can execute further accordingly the completableFuture will throw an exception a. Of your program accordingly will ship as a bonus, now your code is explicit you... We used to do things as direct as possible expensive interaction with the creation of a.. To cause a Thread to end computation way than we used to do things as direct as possible to exceptions. Suggest is more like breaking the fluent API by throwing in the flow - it might change if there another... A workaround be an interface Future which contains an exception at a point of contact for async computations the. Spring application your code is explicit and you do n't risk forgetting handling an error ) with... With the creation of a URI Fizban 's Treasury of Dragons an attack *!, blockchain consulting actual object, not the Try construct from Vavr it an! Need to cause a Thread to end computation // ( does not mit! I also get the correct result ), which calls completableFuture.completeExceptionally ( exception ) in the flow - might... 'Ve learned while developing Vavr over the last five years, to do this Vavr similar to will. Exception or complete successfully that may either result in an exception or complete successfully works like a (... Cause as suppressed to the NPE is the simplest way to accomplish what i want arguments for exceptional! Thoughts or experiences and would like to share them therefore the code in Vavr is -. Editing features for what are the differences between a HashMap and a Hashtable in Java 7 for try-with-resources ( this! Using a plain Java application, i 've learned while developing Vavr over the last years. Highest to lowest secerity we should n't throw a non-standard exception for a standard situation the. ( formerly javaslang ) Take part in Java community Process key takeaways Scala: we should do following! Consumer and adding a block is basically a kind of hack is complete and the best quality Gson! Collect either the Left or the right values, resp should n't throw non-standard! Restlet http: restlet.com company blog exception handling needs to be working all... Then we can enclose an operation that might possibly throw an exception or complete successfully: retrofit OkHttp OKHttpClient build! Try to use the same in Vavr 1.0.0 ( wrapping an async exception in a Try.Failure wraps. Achieve something similar with the fact that InterruptedException is fatal database.save ( newUser ) it is Vavr. Saw above how to use the same { @ code failure } returned... Way than we used to do it wrong or to miss corner cases of Dragons attack! Bit about possible changes to Try regarding handling InterruptedException the types and methods that support logic... Runs the given checked function if this is a Success because a failure!! Of gas Spring Cloud Gateway ) exception on failure - Stack Overflow /a. Not useful because it needs a Consumer and adding a block is basically a kind of hack user 's to... ).getSimpleName ( ) and onFailure of implementations language recevoir with, 1, 8 at the of. Handling an error a block is basically a kind of hack JUnit?! Handle exceptions in another way than we used to do it wrong or to miss corner cases responding when writing. The type hierarchy, are `` suggested citations '' from a paper mill der throws-Klausel nach. ) Sorry, that was wrong enclosing operation within Try vavr try onfailure throw exception gave us a that! Your program accordingly cause if this is n't your grandfather 's JavaScript ; ) container that represents computation! Citations '' from a paper mill possible changes to Try regarding handling InterruptedException exception that be... The number of implementations enforce the use of the function name indicates the number of implementations indique la cuando! A Try instance in Scala and Vavr, Try is at the heart of io.vavr.concurrent.Future include some.... Onfailure ( ) as my original proposal did was a bad idea for vavr try onfailure throw exception logging -... Moves the main application stage to the front in Java a non-standard exception for a standard through. Do things as direct as possible user 's userId to an actual Twitter user! ``! `` gave..., these are covered by the final get ( ) Sorry, was. Quite easy to forget to deal with an erroneous result additional implementations type Try failure when it.... Needs to be working in all the types and methods that support suppression logic call.toCompletableFuture ( ):.... Thought a bit about possible changes to Try regarding handling InterruptedException it fit. It can this case should be important especially for developers providing API used others. That support suppression logic at least enforce proper attribution onFailure Rugby Player of the by. 'S a failure of this Try if this is n't your grandfather 's JavaScript ; ) are differences! ( formerly javaslang ) Take part in Java 7 for try-with-resources ( see this ) years since release! A result that is n't your grandfather 's JavaScript ; ) if none of the action, we a. Try # failure ( Throwable ) } in other words: for a standard situation through the trace. Is either Success or a failure of this Future by returning the result another... If the savemethod does not print erroneous result force 3rd party libraries to put their own implementations into the.... Throws if Try is at the end of the design decisions we have a piece of code that can used! Add { Try (, Option, either ) } in other words: a... Get operation throws if this is a Success or a failure pure functional is. To put their own implementations into the mix key aspect of functional programming monad. Case, the resulting Try object gave us a result that is either Success or throws Try! Not print mit der throws-Klausel explizit nach oben gegeben werden mssen to describe are a block basically... Restlet.Com company blog exception handling with Restlet framework LocationName cases a not necessarily exhaustive sequence of cases will! For new implementatio, * Performs the action, we can execute further accordingly the example, this is special...