On Fri, 20 Nov 2020 19:51:57 GMT, Mandy Chung <mch...@openjdk.org> wrote:
>> @plevart I'm okay with this slight performance improvement. > > I have a fresh look at the different options we have explored (lots of > challenges in finding the right API with security, usability and performance > issues to consider). I agree with Remi that we should keep the design and > API simple and makes it easier to invoke default methods with today's Proxy > API. We can design a better Proxy API in the future. > > The options we have explored are: > 1. static `InvocationHandler::invokeDefault` method > 2. abstract `DelegatingInvocationHandler` class with a protected > `invokeDefault` method > 3. a new `newProxyInstance` factory method taking a function that produces an > invocation handler with the ability to invoke a default method via a > `superHandler` > > (1) is very simple API but caller-sensitive. No other API change. Access > check done at default method invocation time (which is consistent with the > core reflection `Method::invoke`). It shares the caller class caching in > `Method::checkAccess` which helps the performance. The performance > overhead is slightly higher than (2) & (3) which does access check at proxy > creation time. > > (2) is simple and I like that the `invokeDefault` can be enforced to be > invoked only by the proxy's invocation handler. However this requires more > API changes (including `newProxyInstance`, `getInvocationHandler`, and new > unchecked exception type). (3) is clever but a bit over-rotated (how Alan > describes it) to allow it to be expressed in a lambda expression. If an > invocation handler wants to save `superHandler`, it can't assign it to a > final field in lambda and would need to workaround it writing to an array > element. > > I will go with option (1) - static `invokeDefault` method [1] unless there > is any objection. > > Here is the specdiff: > http://cr.openjdk.java.net/~mchung/jdk16/webrevs/8159746/specdiff/ > > [1] > http://cr.openjdk.java.net/~mchung/jdk16/webrevs/8159746/api/java.base/java/lang/reflect/InvocationHandler.html#invokeDefault(java.lang.Object,java.lang.reflect.Method,java.lang.Object...) Hi Mandy, thanks for taking the time to explore all the different options, The solution 1 is fine for me. ------------- PR: https://git.openjdk.java.net/jdk/pull/313
