On 17/10/2020 1:23 am, Kim Barrett wrote:
On Fri, 16 Oct 2020 05:41:17 GMT, David Holmes <dhol...@openjdk.org> wrote:
Kim Barrett has updated the pull request with a new target base due to a merge
or a rebase. The incremental webrev
excludes the unrelated changes brought in by the merge/rebase. The pull request
contains 11 additional commits since
the last revision:
- Merge branch 'master' into refersto
- More explicit refersTo0 comment.
- simplify test
- cleanup nits from Mandy
- use Object instead of TestObject
- improve refersTo0 descriptions
- basic functional test
- change referent access
- expand test
- remove CMS comment
- ... and 1 more: https://git.openjdk.java.net/jdk/compare/b5adeaad...ab4e519b
src/java.base/share/classes/java/lang/ref/Reference.java line 348:
346: * Tests if this reference object refers to {@code obj}. If {@code
obj} is
347: * {@code null}, this method returns {@code true} if this reference
object
348: * refers to {@code null} or has been cleared.
Is there actually a distinction between clearing and referring to null?
A (not very useful) Reference can be created with a null referent.
Yes but you cannot distinguish between the two cases yet this wording is
trying to make that distinction. My concern is interaction with the
wording here:
* @return {@code true} if and only if {@code obj} is the referent
* of this reference object
As written it implies to me that given:
Object o = new Object();
PhantomReference r = new PhantomReference(o);
r.clear();
assert(r.refersTo(null)); // pass or fail?
then the assert should fail because "null" was not the referent, as r
has been cleared - which are two distinct cases according to the initial
java doc. The initial doc would be clearer if it stated words to the
effect of:
"returns {@code true} if this reference object refers to {@code null}
(either because it was constructed that way, or it has been cleared)."
or else the @return doc needs to account for the null case more
explicitly. Also why the "if and only if" in the @return doc versus a
simple "if"? What is being emphasized by using "if and only if"?
Cheers,
David
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PR: https://git.openjdk.java.net/jdk/pull/498
