JEP 102 Process Updates revised API draft

[Chris Hegarty]

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.Riggs at 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
>