> Hi, > > This patch adds an asExact() combinator to VarHandle, that will return a new > VarHandle that performs exact type checks, similar to > MethodHandle::invokeExact, to help developers catch inexact VarHandle usage, > which can lead to performance degradation. > > This is implemented using a boolean flag in VarForm. If the flag is set, the > exact type of the invocation is checked against the exact type in the > VarForm. If there is a mismatch, a WrongMethodTypeException is thrown. > > Other than that, there is also an asGeneric() combinator added that does the > inverse operation (thanks to Rémi for the suggestion). I've also added The > `@Hidden` annotation to the VarHandleGuards methods, as well as a > type-checking helper method called from the generic invocation lambda form, > so that the stack trace we get points at the location where the VarHandle is > being used. > > Thanks, > Jorn
Jorn Vernee has updated the pull request incrementally with three additional commits since the last revision: - Fix whitespace - Comment out VarHandleGuards generator code - Makes exactness a property of a VarHandle, not a VarForm, since the latter are shared. Use handle.accessModeType to get the exact type of the VarHandle. ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/843/files - new: https://git.openjdk.java.net/jdk/pull/843/files/dc1f9ecf..be9e940d Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=843&range=02 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=843&range=01-02 Stats: 410 lines in 11 files changed: 90 ins; 71 del; 249 mod Patch: https://git.openjdk.java.net/jdk/pull/843.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/843/head:pull/843 PR: https://git.openjdk.java.net/jdk/pull/843