From 5d2613873c0ba380aeae463aaa39563c14fbe08b Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@leastfixedpoint.com>
Date: Tue, 30 Apr 2024 21:25:34 +0200
Subject: [PATCH] Switch to monotonic System.nanoTime()

---
 src/main/java/org/syndicate_lang/actors/Promise.java        | 6 +++---
 .../org/syndicate_lang/actors/example/example2/Main.java    | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/main/java/org/syndicate_lang/actors/Promise.java b/src/main/java/org/syndicate_lang/actors/Promise.java
index a3657ec..db23cbc 100644
--- a/src/main/java/org/syndicate_lang/actors/Promise.java
+++ b/src/main/java/org/syndicate_lang/actors/Promise.java
@@ -170,11 +170,11 @@ public class Promise<T> implements Future<T> {
             if (delay == -1) {
                 while (this.isPending()) this.wait();
             } else {
-                long targetTime = System.currentTimeMillis() + unit.toMillis(delay);
+                long targetTime = System.nanoTime() + unit.toNanos(delay);
                 while (this.isPending()) {
-                    long now = System.currentTimeMillis();
+                    long now = System.nanoTime();
                     if (now >= targetTime) throw TIMEOUT_WAITING_FOR_PROMISE_RESOLUTION;
-                    this.wait(targetTime - now);
+                    this.wait(TimeUnit.NANOSECONDS.toMillis(targetTime - now));
                 }
             }
         }
diff --git a/src/test/java/org/syndicate_lang/actors/example/example2/Main.java b/src/test/java/org/syndicate_lang/actors/example/example2/Main.java
index a67435f..f19148d 100644
--- a/src/test/java/org/syndicate_lang/actors/example/example2/Main.java
+++ b/src/test/java/org/syndicate_lang/actors/example/example2/Main.java
@@ -47,7 +47,7 @@ public class Main extends Entity {
         t.message_(_forwarders.get(0), new IForwarder.SetPeer(_forwarders.get(_nActors - 1)));
         t.later(t0 -> {
             t0.log().info("Start");
-            this._startTime = System.currentTimeMillis();
+            this._startTime = System.nanoTime();
             _forwarders.forEach(a -> t0.message_(a, new IForwarder.HandleMessage(0)));
         });
     }
@@ -57,7 +57,7 @@ public class Main extends Entity {
         if (body instanceof IForwarder.HandleMessage) {
             this._remainingToReceive--;
             if (this._remainingToReceive == 0) {
-                double delta = (System.currentTimeMillis() - this._startTime) / 1000.0;
+                double delta = (System.nanoTime() - this._startTime) / 1000000000.0;
                 long nMessages = (long) _nActors * (long) _nRounds;
                 double hz = nMessages / delta;
                 turn.quit();