From 4b17df85b365f1f1e5a3b32c537a7ead4c94111d Mon Sep 17 00:00:00 2001
From: James Hilliard <james.hilliard1@gmail.com>
Date: Wed, 26 May 2021 23:10:22 -0600
Subject: [PATCH] Use monotonic clocks for MUXPool and fix timeout calculation
 bug.

---
 .../main/java/org/jpos/q2/iso/MUXPool.java    | 27 ++++++++++---------
 .../java/org/jpos/q2/iso/MUXPoolTest.java     |  2 +-
 2 files changed, 16 insertions(+), 13 deletions(-)

diff --git a/jpos/src/main/java/org/jpos/q2/iso/MUXPool.java b/jpos/src/main/java/org/jpos/q2/iso/MUXPool.java
index f1cbde9f69..34593e4702 100644
--- a/jpos/src/main/java/org/jpos/q2/iso/MUXPool.java
+++ b/jpos/src/main/java/org/jpos/q2/iso/MUXPool.java
@@ -27,6 +27,7 @@
 import org.jpos.util.NameRegistrar;
 
 import java.io.IOException;
+import java.time.Duration;
 import java.util.StringTokenizer;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -70,13 +71,12 @@ public void stopService () {
         NameRegistrar.unregister ("mux."+getName ());
     }
     public ISOMsg request (ISOMsg m, long timeout) throws ISOException {
-        long maxWait = System.currentTimeMillis() + timeout;
-        MUX mux = getMUX(m,maxWait);
+        Duration maxWait = Duration.ofNanos(System.nanoTime()).plus(Duration.ofMillis(timeout));
+        MUX mux = getMUX(m,timeout);
 
         if (mux != null) {
-            timeout = maxWait - System.currentTimeMillis();
-            if (timeout >= 0)
-                return mux.request (m, timeout);
+            if (timeout > 0)
+                return mux.request (m, Math.max(maxWait.minus(Duration.ofNanos(System.nanoTime())).toMillis(), 1L));
         }
         return null;
     }
@@ -96,15 +96,19 @@ public boolean isConnected() {
         return false;
     }
     protected MUX firstAvailableMUX (long maxWait) {
+        Duration now = Duration.ofNanos(System.nanoTime());
+        Duration timeout = Duration.ofMillis(maxWait).plus(now);
         do {
             for (MUX m : mux)
                 if (isUsable(m))
                     return m;
             ISOUtil.sleep (1000);
-        } while (System.currentTimeMillis() < maxWait);
+        } while (Duration.ofNanos(System.nanoTime()).compareTo(timeout) < 0);
         return null;
     }
     protected MUX nextAvailableMUX (int mnumber, long maxWait) {
+        Duration now = Duration.ofNanos(System.nanoTime());
+        Duration timeout = Duration.ofMillis(maxWait).plus(now);
         do {
             for (int i=0; i<mux.length; i++) {
                 int j = (mnumber+i) % mux.length;
@@ -113,7 +117,7 @@ protected MUX nextAvailableMUX (int mnumber, long maxWait) {
                 msgno.incrementAndGet();
             }
             ISOUtil.sleep (1000);
-        } while (System.currentTimeMillis() < maxWait);
+        } while (Duration.ofNanos(System.nanoTime()).compareTo(timeout) < 0);
         return null;
     }
     private String[] toStringArray (String s) {
@@ -129,13 +133,12 @@ private String[] toStringArray (String s) {
     public void request (ISOMsg m, long timeout, final ISOResponseListener r, final Object handBack) 
         throws ISOException 
     {
-        long maxWait = System.currentTimeMillis() + timeout;
-        MUX mux = getMUX(m,maxWait);
+        Duration maxWait = Duration.ofNanos(System.nanoTime()).plus(Duration.ofMillis(timeout));
+        MUX mux = getMUX(m,timeout);
 
         if (mux != null) {
-            timeout = maxWait - System.currentTimeMillis();
-            if (timeout >= 0)
-                mux.request(m, timeout,r, handBack);
+            if (timeout > 0)
+                mux.request(m, Math.max(maxWait.minus(Duration.ofNanos(System.nanoTime())).toMillis(), 1L),r, handBack);
             else {
                 new Thread() {
                     public void run() {
diff --git a/jpos/src/test/java/org/jpos/q2/iso/MUXPoolTest.java b/jpos/src/test/java/org/jpos/q2/iso/MUXPoolTest.java
index be456e786d..6f95724e36 100644
--- a/jpos/src/test/java/org/jpos/q2/iso/MUXPoolTest.java
+++ b/jpos/src/test/java/org/jpos/q2/iso/MUXPoolTest.java
@@ -93,7 +93,7 @@ public void testRequestThrowsNullPointerException() throws Throwable {
             if (isJavaVersionAtMost(JAVA_14)) {
                 assertNull(ex.getMessage(), "ex.getMessage()");
             } else {
-                assertEquals("Cannot read the array length because \"<local4>\" is null", ex.getMessage(), "ex.getMessage()");
+                assertEquals("Cannot read the array length because \"<local6>\" is null", ex.getMessage(), "ex.getMessage()");
             }
         }
     }