AMQ-9552: Add metric lastMessageTimestamp to StatisticsBroker based o…

…n lastSampleTime of metric enqueues,

 StatisticImpl#lastSampleTime is set to zero be default,
 add method StatisticImpl#getLastSampleTimeOrStartTime to maintain currect behaviour

activemq-broker/src/main/java/org/apache/activemq/broker/jmx/NetworkDestinationView.java

@@ -74,7 +74,7 @@ public void messageSent(){
     }
 
     public long getLastAccessTime(){
-        return timeStatistic.getLastSampleTime();
+        return timeStatistic.getLastSampleTimeOrStartTime();
     }
 
     public void close(){

activemq-broker/src/main/java/org/apache/activemq/plugin/StatisticsBroker.java

@@ -160,6 +160,10 @@ else if (dest instanceof Topic) {
                                 tempFirstMessage.clear();
                             }
                         }
+                        // NOTICE: Client-side, you may get the broker "now" Timestamp by msg.getJMSTimestamp()
+                        // This allows for calculating inactivity.
+                        // When no message is enqueued since broker start (or statistics reset) it returns 0
+                        statsMessage.setLong("lastMessageTimestamp", stats.getEnqueues().getLastSampleTime());
                         statsMessage.setJMSCorrelationID(messageSend.getCorrelationId());
                         sendStats(producerExchange.getConnectionContext(), statsMessage, replyTo);
                     }

activemq-client/src/main/java/org/apache/activemq/management/JMSEndpointStatsImpl.java

@@ -129,7 +129,7 @@ public String toString() {
 
     public void onMessage() {
         if (enabled) {
-            long start = messageCount.getLastSampleTime();
+            long start = messageCount.getLastSampleTimeOrStartTime();
             messageCount.increment();
             long end = messageCount.getLastSampleTime();
             messageRateTime.addTime(end - start);

activemq-client/src/main/java/org/apache/activemq/management/StatisticImpl.java

@@ -37,13 +37,13 @@ public StatisticImpl(String name, String unit, String description) {
         this.unit = unit;
         this.description = description;
         this.startTime = System.currentTimeMillis();
-        this.lastSampleTime = this.startTime;
+        this.lastSampleTime = 0;
     }
 
     public synchronized void reset() {
         if(isDoReset()) {
             this.startTime = System.currentTimeMillis();
-            this.lastSampleTime = this.startTime;
+            this.lastSampleTime = 0;
         }
     }
 
@@ -80,6 +80,9 @@ public synchronized long getLastSampleTime() {
         return this.lastSampleTime;
     }
 
+    public synchronized long getLastSampleTimeOrStartTime(){
+        return lastSampleTime == 0 ? startTime : lastSampleTime;
+    }
     /**
      * @return the enabled
      */

activemq-unit-tests/src/test/java/org/apache/activemq/management/TimeStatisticTest.java

@@ -30,6 +30,8 @@ public void testStatistic() throws Exception {
         TimeStatisticImpl stat = new TimeStatisticImpl("myTimer", "millis", "myDescription");
         assertStatistic(stat, "myTimer", "millis", "myDescription");
 
+        assertEquals("Check if lastSimpleTime is 0 for new statistic", 0, stat.getLastSampleTime());
+
         assertEquals(0, stat.getCount());
 
         stat.addTime(100);
@@ -59,6 +61,7 @@ public void testStatistic() throws Exception {
         LOG.info("Stat is: " + stat);
 
         stat.reset();
+        assertEquals("Check if lastSimpleTime is 0 on statistic reset", 0, stat.getLastSampleTime());
 
         assertEquals(0, stat.getCount());
         assertEquals(0, stat.getMinTime());

activemq-unit-tests/src/test/java/org/apache/activemq/plugin/BrokerStatisticsPluginTest.java

@@ -218,6 +218,7 @@ public void testDestinationStatsWithFirstMessageTimestamp() throws Exception {
         assertEquals(1, reply.getLong("size"));
         assertTrue(reply.getJMSTimestamp() > 0);
         assertTrue(reply.getLong("firstMessageTimestamp") > 0);
+        assertTrue(reply.getLong("lastMessageTimestamp") >= msg.getJMSTimestamp());
         // Assert that we got the brokerInTime for the first message in queue as value of key "firstMessageTimestamp"
         assertTrue(System.currentTimeMillis() >= reply.getLong("firstMessageTimestamp"));
         assertEquals(Message.DEFAULT_PRIORITY, reply.getJMSPriority());