A small implementation issue.
I couldn't find anything in the code or the spec about whether the thread that
executes a handler is or isn't a daemon thread. My first inclination was to make
sure that the handler threads are daemon threads, similar to most system-created
threads.
But in thinking about use cases, a handler might want to do some cleanup before
saving state and exiting. The cleanup might end up causing all non-daemon
threads to exit, which would pull the rug out from under the handler thread
while it's in the midst of further cleanup or saving state. That would be bad.
Thus I'm thinking that the handler threads should be non-daemon threads, and
further that this should be specified.
What do you think?
s'marks
On 2/1/16 8:02 AM, Roger Riggs wrote:
Please review an API addition to handle signals such as SIGINT, SIGHUP, and
SIGTERM.
This JEP 260 motivated alternative to sun.misc.Signal supports the use case for
interactive applications that need to handle Control-C and other signals.
The new java.util.Signal class provides a settable primary signal handler and a
default
signal handler. The primary signal handler can be unregistered and handling is
restored
to the default signal handler. System initialization registers default signal
handlers
to terminate on SIGINT, SIGHUP, and SIGTERM. Use of the Signal API requires
a permission if a SecurityManager is set.
The sun.misc.Signal implementation is modified to be layered on a common
thread and dispatch mechanism. The VM handling of native signals is not
affected.
The command option to reduce signal use by the runtime with -Xrs is unmodified.
The changes to hotspot are minimal to rename the hardcoded callback to the Java
Signal dispatcher.
Please review and comment on the API and implementation.
javadoc:
http://cr.openjdk.java.net/~rriggs/signal-doc/
Webrev:
jdk: http://cr.openjdk.java.net/~rriggs/webrev-signal-8087286/
hotspot: http://cr.openjdk.java.net/~rriggs/webrev-hs-signal-8087286/
Issue:
https://bugs.openjdk.java.net/browse/JDK-8087286
JEP 260:
https://bugs.openjdk.java.net/browse/JDK-8132928
Thanks, Roger
