пт, 9 июл. 2021 г. в 00:07, Mark Thomas <ma...@apache.org>: > > On 08/07/2021 22:05, ma...@apache.org wrote: > > This is an automated email from the ASF dual-hosted git repository. > > > > markt pushed a commit to branch main > > in repository https://gitbox.apache.org/repos/asf/tomcat.git > > > > commit 2fcb104294b2676154cb08f00d5665d668792280 > > Author: Mark Thomas <ma...@apache.org> > > AuthorDate: Thu Jul 8 22:02:26 2021 +0100 > > > > Add support for coercing LambdaExpression to any functional interface > > The implementation for this turned out to be a lot simpler than I > initially thought. I can;t help be think I've missed something. Please > try and find ways to break this. If you do, feel free to add a disabled > out test case and I'll take a look.
Re: " if (obj instanceof LambdaExpression && type.getAnnotation(FunctionalInterface.class) != null) " 1. IIRC, using @FunctionalInterface annotation is a hint, not a requirement. E.g. at https://docs.oracle.com/javase/8/docs/api/java/lang/FunctionalInterface.html "the compiler will treat any interface meeting the definition"... E.g. lambdas can be used with legacy code that does not use that annotation. 2. Inheritance? If the annotation is applied not on this class or interface, but on some of its parents. Docs for "AnnotatedElement.getAnnotation(...)" - reading their definition of "present", I think that that method goes up a hierarchy of classes, but it does not go up a hierarchy of interfaces. https://docs.oracle.com/javase/8/docs/api/java/lang/reflect/AnnotatedElement.html Example: a "SerializablePredicate" interface, https://vaadin.com/api/framework/8.13.2/com/vaadin/server/SerializablePredicate.html https://github.com/vaadin/framework/blob/master/server/src/main/java/com/vaadin/server/SerializablePredicate.java The SerializablePredicate interface does not redeclare @FunctionalInterface, but it is a functional interface. > Re: "if (!Modifier.isAbstract(method.getModifiers())) { throw...." 3. While only one method is abstract, other methods may be called: (a) methods defined by Object - equals(), hashCode() and toString(), (b) default methods defined in an interface. The current code throws an ELException. There is some sample code (though maybe not best) to deal with (a) at https://docs.oracle.com/javase/8/docs/technotes/guides/reflection/proxy.html I do not know how people deal with (b). It may be that InvocationHandler won't see those calls to default methods. (When I studied java proxies, that feature did not exist yet.) I wonder how Java itself (a java compiler) deals with coercion of lambdas to interfaces. Either it generates calls to some helper API, or it just repeats the same boilerplate code over and over. Best regards, Konstantin Kolinko --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@tomcat.apache.org For additional commands, e-mail: dev-h...@tomcat.apache.org
