On 11/25/2015 03:05 AM, Peter Levart wrote:
On 11/25/2015 01:59 AM, Martin Buchholz wrote:
On Tue, Nov 24, 2015 at 2:30 PM, Peter Levart <peter.lev...@gmail.com
<mailto:peter.lev...@gmail.com>> wrote:
What do you think of exception cloning?
Making copies of java objects has historically been troublesome (e.g.
Cloneable).
I was only thinking of Cloneable. Serialization is troublesome. If Throwable was
retrofitted to implement Cloneable and have the following new static method:
I still think this would be a useful feature, assuming no hidden snags.
In addition to CompletableFuture, we might be able to use it instead of
emulating a variant of it in ForkJoinTask.getThrowableException.
There are probably other candidate uses elsewhere (although I can't
think of any offhand).
In the mean time though, I think using addSuppressed in
CompletableFuture.whenComplete is the best we can do, and
surely better than not doing it.
-Doug
/**
* {@link Object#clone() Clones} given {@code exception} and returns it's
clone which
* shares all state with original exception (shallow clone) except for the
possible list of already
* {@link #addSuppressed(Throwable) added} {@link #getSuppressed()
suppressed}
* exceptions. The suppressed exception instances are not cloned, just the
* list containing them. Further {@link #addSuppressed(Throwable)
additions}
* to the suppressed exceptions of the returned clone instance
* don't affect the suppressed exceptions of original exception and vice
versa.
*
* @param exception the exception to clone.
* @param <T> the type of exception
* @return shallow clone of given exception with suppressed exception
* list shallow-cloned
* @since 1.9
*/
@SuppressWarnings("unchecked")
public static <T extends Throwable> T clone(T exception) {
try {
Throwable clone = (Throwable) exception.clone();
if (clone.suppressedExceptions != null &&
clone.suppressedExceptions != SUPPRESSED_SENTINEL) {
clone.suppressedExceptions = new
ArrayList<>(clone.suppressedExceptions);
}
return (T) clone;
} catch (CloneNotSupportedException e) {
throw new InternalError(e);
}
}
...then would you prefer using it or would you nevertheless prefer swapping the
roles of exceptions in whenComplete?
Regards, Peter
