Adds tlm for beans registered and unregistered

src/main/java/org/datadog/jmxfetch/Instance.java

@@ -788,6 +788,11 @@ public synchronized void trackBean(ObjectName beanName) {
             log.warn("Cannot get bean attributes or class name: " + e.getMessage(), e);
         }
         log.debug("Bean registration processed. '{}'. Found {} matching attributes.", beanName, matchedAttributesForBean);
+
+        if (instanceTelemetryBean != null) {
+            int beanRegisterationsHandled = instanceTelemetryBean.getBeanRegistrationsHandled();
+            instanceTelemetryBean.setBeanRegistrationsHandled(beanRegisterationsHandled + 1);
+        }
     }
 
     /** Removes any matching attributes from the specified bean. */
@@ -811,6 +816,11 @@ public synchronized void untrackBean(ObjectName beanName) {
             removedMetrics,
             beanName);
         this.metricCountForMatchingAttributes -= removedMetrics;
+
+        if (instanceTelemetryBean != null) {
+            int beanUnRegistrationsHandled = instanceTelemetryBean.getBeanUnregistrationsHandled();
+            instanceTelemetryBean.setBeanUnregistrationsHandled(beanUnRegistrationsHandled + 1);
+        }
     }
 
     private void subscribeToBeans() {

src/main/java/org/datadog/jmxfetch/util/InstanceTelemetry.java

@@ -9,6 +9,8 @@ public class InstanceTelemetry implements InstanceTelemetryMBean {
     private int metricCount;
     private int wildcardDomainQueryCount;
     private double beanMatchRatio;
+    private int beanRegistrationsHandled;
+    private int beanUnregistrationsHandled;
 
     /** Jmxfetch telemetry bean constructor. */
     public InstanceTelemetry() {
@@ -26,6 +28,8 @@ public InstanceTelemetry() {
         // - numBeansWithoutMatchingAttributes
         // a bit wordy though.
         beanMatchRatio = 0.0;
+        beanRegistrationsHandled = 0;
+        beanUnregistrationsHandled = 0;
     }
 
     public int getBeansFetched() {
@@ -48,6 +52,14 @@ public double getBeanMatchRatio() {
         return beanMatchRatio;
     }
 
+    public int getBeanRegistrationsHandled() {
+        return beanRegistrationsHandled;
+    }
+
+    public int getBeanUnregistrationsHandled() {
+        return beanUnregistrationsHandled;
+    }
+
     public void setBeansFetched(int count) {
         beansFetched = count;
     }
@@ -68,4 +80,12 @@ public void setBeanMatchRatio(double ratio) {
         beanMatchRatio = ratio;
     }
 
+    public void setBeanRegistrationsHandled(int count) {
+        beanRegistrationsHandled = count;
+    }
+
+    public void setBeanUnregistrationsHandled(int count) {
+        beanUnregistrationsHandled = count;
+    }
+
 }

src/test/java/org/datadog/jmxfetch/TestInstance.java

@@ -277,6 +277,12 @@ public void testBeanSubscription() throws Exception {
         metrics = getMetrics();
 
         assertEquals(numRegisteredAttributes, metrics.size());
+
+        List<Instance> instances = getInstances();
+        assertEquals(1, instances.size());
+        Instance i = instances.get(0);
+        assertEquals(2, i.getInstanceTelemetryBean().getBeanRegistrationsHandled());
+        assertEquals(0, i.getInstanceTelemetryBean().getBeanUnregistrationsHandled());
     }
 
     @Test
@@ -319,8 +325,13 @@ public void testBeanUnsubscription() throws Exception {
         assertEquals(numRegisteredAttributes, metrics.size());
         // Which is why this second check exists, it reflects the running total of metrics
         // collected which is used to determine if new attributes can be added
-        Instance i = app.getInstances().get(0);
+        List<Instance> instances = getInstances();
+        assertEquals(1, instances.size());
+        Instance i = instances.get(0);
         assertEquals(numRegisteredAttributes, i.getCurrentNumberOfMetrics());
+
+        assertEquals(1, i.getInstanceTelemetryBean().getBeanRegistrationsHandled());
+        assertEquals(1, i.getInstanceTelemetryBean().getBeanUnregistrationsHandled());
     }
 
     @Test