On 03/12/2015 02:39 PM, Roger Riggs wrote:
Hi,
Just a thought, it might be useful to introduce a public subtype of
Process that is
returned from ProcessBuilder for which the guarantees about behavior
could be
tighter (no UOEs). It would also provide a place to document the
behaviors
now spread across ProcessBuilder and Process.
$.02, Roger
That was my thinking too today. A Process2 or XProcess? If ProcessHandle
was an interface this subtype could implement it (back to square one). I
think it could be an interface if Process2 was not publicly extendable
(package-protected constructor) as it would not represent part of
extensible API.
Does that mean that we would need additional methods
ProcessBuilder.start2() / Runtime.exec2() too?
Peter
On 3/12/15 9:09 AM, Chris Hegarty wrote:
This is looking good, still looking at the detail… just a quick comment.
It may be possible to remove the UOE from Process.onExit, if you
implement the “never to be used” default without using ProcessHandle?
diff --git a/src/java.base/share/classes/java/lang/Process.java
b/src/java.base/share/classes/java/lang/Process.java
--- a/src/java.base/share/classes/java/lang/Process.java
+++ b/src/java.base/share/classes/java/lang/Process.java
@@ -360,20 +360,20 @@
* a unique instance is returned for each call to {@code onExit}.
*
* @throws IllegalStateException if the process is the current
process
- * @throws UnsupportedOperationException if the Process
implementation
- * does not support this operation
- * @implSpec
- * The Process instances created by {@link ProcessBuilder
ProcessBuilder} return
- * a {@code ComputableFuture<Process>} equivalent
- * to {@code toHandle().onExit().thenApply(ph -> this)}.
*
- * @implNote
- * The implementation of this method is {@link #toHandle
toHandle().onExit().thenApply(ph -> this)}.
- * Override to provide more specific onExit behavior.
* @since 1.9
*/
public CompletableFuture<Process> onExit() {
- return toHandle().onExit().thenApply((ph) -> this);
+ return CompletableFuture.supplyAsync(this::wait0);
+ }
+
+ private Process wait0() {
+ while(true) {
+ try {
+ waitFor();
+ return this;
+ } catch (InterruptedException x) {}
+ }
}
/**
-Chris.
On 11 Mar 2015, at 19:58, Roger Riggs <roger.ri...@oracle.com> wrote:
Hi,
The recommendations have been applied to the javadoc and the sandbox
JDK-8046092-branch.
http://cr.openjdk.java.net/~rriggs/ph-apidraft/
Some operations on a Process take an extra dereference due to the
delegation to ProcessHandle.
For example, getting the cputime or startTime of the process:
Process p = ...
Duration d = p.toHandle().info().totalCpuDuration();
Instant start = p.toHandle().info().startInstant();
As do the listing of children; convenience methods could be
introduced with the UOE possibility
but that is a risk only for externally defined Process subtypes.
Developers working with Processes should not have to deal with
ProcessHandle
to get information about the processes they spawn.
Comments appreciated, Roger
