Re: [cdi-dev] Adding Lambdas as CDI beans

Am 17.10.2015 um 15:03 schrieb John D. Ament <john.d.ament(a)gmail.com&gt;: Sven, I'm a little curious, why do they need to avoid serializable contexts? In all honesty, I use app scoped functions, predicates in my code, at least in a couple of places. Lambdas are specifically meant for operations, not data, so they should be in a highly reusable scope (in my opinion at least). On the flip side, I have a hard time justifying needing to provide injectable beans for lambdas since good encapsulation should indicate they're only used in a single spot. John On Sat, Oct 17, 2015 at 7:51 AM Sven Linstaedt <sven.linstaedt(a)gmail.com&gt; wrote: > Just one question: Who is on charge and is able of managing this unmanaged instances, e.g. lifecycle, serialization, concurrency (e.g. when dealing with closures)? > > Functional programming and DI seem to be somehow disjunct in this case. E.g. manually setting up observers seem to better fit extension than normal application code. > > On the other side, specifying producer methods or fields, that are injectable and return lambda expressions seems to be a no brainier for CDI, is not it? As long as they are not scoped in a serializable context. > > Have a nice weekend > Sven > > -- sent by phone > >> Am 17.10.2015 um 11:06 schrieb David Blevins <david.blevins(a)gmail.com&gt;: >> >> In brainstorming mode about fun that could be made possible with Java 8 and Java EE. >> >> Question in my mind is: is there some way we could make it possible for Lambdas or Method Refs to be CDI beans? >> >> It goes against the grain obviously as CDI creation is very much a “Don’t call us, we’ll call you” kind of thing. The VM dynamically creates a wrapper object around the Lambda or method reference and it implements the given interface. >> >> To make it work, there would need to be some non-producer method way of saying “put this thing in the context with these qualifiers”. >> >> Imagine a method somewhere that would allow you to: >> >> public <T> void addObserver(java.util.function.Consumer<T> observer, Annotation... qualifiers); >> >> >> Then you could take advantage as follows: >> >> final List<URI> uris = new ArrayList<>(); >> // @Observes URI >> addObserver((Consumer<URI>) uris::add); >> >> // @Observes Thread >> addObserver(Runtime.getRuntime()::addShutdownHook); >> >> // @Observes Runnable >> addObserver((Consumer<Runnable>) Executors.newFixedThreadPool(3)::submit); >> >> // @Observes URI >> addObserver((Consumer<URI>) System.out::println, new AnnotationLiteral<Fine>() { >> }); >> >> // @Observes Handler >> final Logger logger = Logger.getLogger("somewhere"); >> addObserver(logger::addHandler); // add handlers via event >> >> // @Observes @Fine String >> addObserver((Consumer<String>) logger::fine, new AnnotationLiteral<Fine>() {}); >> } >> >> >> >> -David >> >> >> >> -- >> David Blevins >> http://twitter.com/dblevins >> http://www.tomitribe.com >> >> _______________________________________________ >> cdi-dev mailing list >> cdi-dev(a)lists.jboss.org >> https://lists.jboss.org/mailman/listinfo/cdi-dev >> >> Note that for all code provided on this list, the provider licenses the code under the Apache License, Version 2 (http://www.apache.org/licenses/LICENSE-2.0.html). For all other ideas provided on this list, the provider waives all patent and other intellectual property rights inherent in such information. > _______________________________________________ > cdi-dev mailing list > cdi-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/cdi-dev > > Note that for all code provided on this list, the provider licenses the code under the Apache License, Version 2 (http://www.apache.org/licenses/LICENSE-2.0.html). For all other ideas provided on this list, the provider waives all patent and other intellectual property rights inherent in such information.