[AMQ-8463] TODO: Squash -- refactor to use generics for stats types

activemq-broker/src/main/java/org/apache/activemq/broker/region/DestinationStatistics.java

@@ -51,15 +51,15 @@ public class DestinationStatistics extends StatsImpl {
     protected CountStatisticImpl networkDequeues;
 
     // [AMQ-8463] Advanced Message Statistics are optionally enabled
-    protected LongStatisticImpl enqueuedMessageBrokerInTime;
-    protected StringStatisticImpl enqueuedMessageClientID;
-    protected StringStatisticImpl enqueuedMessageID;
-    protected LongStatisticImpl enqueuedMessageTimestamp;
-    protected LongStatisticImpl dequeuedMessageBrokerInTime;
-    protected LongStatisticImpl dequeuedMessageBrokerOutTime;
-    protected StringStatisticImpl dequeuedMessageClientID;
-    protected StringStatisticImpl dequeuedMessageID;
-    protected LongStatisticImpl dequeuedMessageTimestamp;
+    protected UnsampledStatisticImpl<Long> enqueuedMessageBrokerInTime;
+    protected UnsampledStatisticImpl<String> enqueuedMessageClientID;
+    protected UnsampledStatisticImpl<String> enqueuedMessageID;
+    protected UnsampledStatisticImpl<Long> enqueuedMessageTimestamp;
+    protected UnsampledStatisticImpl<Long> dequeuedMessageBrokerInTime;
+    protected UnsampledStatisticImpl<Long> dequeuedMessageBrokerOutTime;
+    protected UnsampledStatisticImpl<String> dequeuedMessageClientID;
+    protected UnsampledStatisticImpl<String> dequeuedMessageID;
+    protected UnsampledStatisticImpl<Long> dequeuedMessageTimestamp;
 
     public DestinationStatistics() {
 
@@ -87,16 +87,16 @@ public DestinationStatistics() {
         networkEnqueues = new CountStatisticImpl("networkEnqueues", "The number of messages that have been sent to the destination via network connection");
         networkDequeues = new CountStatisticImpl("networkDequeues", "The number of messages that have been acknowledged from the destination via network connection");
 
-        enqueuedMessageBrokerInTime = new LongStatisticImpl("enqueuedMessageBrokerInTime", "Broker in time (ms) of last enqueued message to the destination");
-        enqueuedMessageClientID = new StringStatisticImpl("enqueuedMessageClientID", "ClientID of last enqueued message to the destination");
-        enqueuedMessageID = new StringStatisticImpl("enqueuedMessageID", "MessageID of last enqueued message to the destination");
-        enqueuedMessageTimestamp = new LongStatisticImpl("enqueuedMessageTimestamp", "Message timestamp of last enqueued message to the destination");
+        enqueuedMessageBrokerInTime = new UnsampledStatisticImpl<>("enqueuedMessageBrokerInTime", "ms", "Broker in time (ms) of last enqueued message to the destination", Long.valueOf(0l));
+        enqueuedMessageClientID = new UnsampledStatisticImpl<>("enqueuedMessageClientID", "id", "ClientID of last enqueued message to the destination", null);
+        enqueuedMessageID = new UnsampledStatisticImpl<>("enqueuedMessageID", "id", "MessageID of last enqueued message to the destination", null);
+        enqueuedMessageTimestamp = new UnsampledStatisticImpl<>("enqueuedMessageTimestamp", "ms", "Message timestamp of last enqueued message to the destination", Long.valueOf(0l));
 
-        dequeuedMessageBrokerInTime = new LongStatisticImpl("dequeuedMessageBrokerInTime", "Broker in time (ms) of last dequeued message to the destination");
-        dequeuedMessageBrokerOutTime = new LongStatisticImpl("dequeuedMessageBrokerOutTime", "Broker out time (ms) of last dequeued message to the destination");
-        dequeuedMessageClientID = new StringStatisticImpl("dequeuedMessageClientID", "ClientID of last dequeued message to the destination");
-        dequeuedMessageID = new StringStatisticImpl("dequeuedMessageID", "MessageID of last dequeued message to the destination");
-        dequeuedMessageTimestamp = new LongStatisticImpl("dequeuedMessageTimestamp", "Message timestamp of last dequeued message to the destination");
+        dequeuedMessageBrokerInTime = new UnsampledStatisticImpl<>("dequeuedMessageBrokerInTime", "ms", "Broker in time (ms) of last dequeued message to the destination", Long.valueOf(0l));
+        dequeuedMessageBrokerOutTime = new UnsampledStatisticImpl<>("dequeuedMessageBrokerOutTime", "ms", "Broker out time (ms) of last dequeued message to the destination", Long.valueOf(0l));
+        dequeuedMessageClientID = new UnsampledStatisticImpl<>("dequeuedMessageClientID", "id", "ClientID of last dequeued message to the destination", null);
+        dequeuedMessageID = new UnsampledStatisticImpl<>("dequeuedMessageID", "id", "MessageID of last dequeued message to the destination", null);
+        dequeuedMessageTimestamp = new UnsampledStatisticImpl<>("dequeuedMessageTimestamp", "ms", "Message timestamp of last dequeued message to the destination", Long.valueOf(0l));
 
         addStatistic("enqueues", enqueues);
         addStatistic("dispatched", dispatched);
@@ -202,39 +202,39 @@ public CountStatisticImpl getNetworkDequeues() {
         return networkDequeues;
     }
 
-    public LongStatisticImpl getEnqueuedMessageBrokerInTime() {
+    public UnsampledStatistic<Long> getEnqueuedMessageBrokerInTime() {
         return enqueuedMessageBrokerInTime;
     }
 
-    public StringStatisticImpl getEnqueuedMessageClientID() {
+    public UnsampledStatistic<String> getEnqueuedMessageClientID() {
         return enqueuedMessageClientID;
     }
 
-    public StringStatisticImpl getEnqueuedMessageID() {
+    public UnsampledStatistic<String> getEnqueuedMessageID() {
         return enqueuedMessageID;
     }
 
-    public LongStatisticImpl getEnqueuedMessageTimestamp() {
+    public UnsampledStatistic<Long> getEnqueuedMessageTimestamp() {
         return enqueuedMessageTimestamp;
     }
 
-    public LongStatisticImpl getDequeuedMessageBrokerInTime() {
+    public UnsampledStatistic<Long> getDequeuedMessageBrokerInTime() {
         return dequeuedMessageBrokerInTime;
     }
 
-    public LongStatisticImpl getDequeuedMessageBrokerOutTime() {
+    public UnsampledStatistic<Long> getDequeuedMessageBrokerOutTime() {
         return dequeuedMessageBrokerOutTime;
     }
 
-    public StringStatisticImpl getDequeuedMessageClientID() {
+    public UnsampledStatistic<String> getDequeuedMessageClientID() {
         return dequeuedMessageClientID;
     }
 
-    public StringStatisticImpl getDequeuedMessageID() {
+    public UnsampledStatistic<String> getDequeuedMessageID() {
         return dequeuedMessageID;
     }
 
-    public LongStatisticImpl getDequeuedMessageTimestamp() {
+    public UnsampledStatistic<Long> getDequeuedMessageTimestamp() {
         return dequeuedMessageTimestamp;
     }
 

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

@@ -22,5 +22,7 @@
  * A marker interface for Statistics without
  * sampleTime or or startTime.
  */
-public interface UnsampledStatistic extends Statistic {}
-
+public interface UnsampledStatistic<T> extends Statistic, Resettable {
+    public T getValue();
+    public void setValue(T value);
+}

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

@@ -16,19 +16,29 @@
  */
 package org.apache.activemq.management;
 
+import java.util.concurrent.atomic.AtomicReference;
+
 /**
- * Base class for a UnsampledStatistic implementation
- * 
+ * UnsampledStatistic<T> implementation
  * 
  */
-public abstract class UnsampledStatisticImpl extends StatisticImpl implements UnsampledStatistic {
+public class UnsampledStatisticImpl<T> extends StatisticImpl implements UnsampledStatistic<T> {
+
+    protected final AtomicReference<T> value = new AtomicReference<>();
+    protected final T defaultValue;
 
-    public UnsampledStatisticImpl(String name, String unit, String description) {
+    public UnsampledStatisticImpl(String name, String unit, String description, T defaultValue) {
         super(name, unit, description, 0l, 0l);
+        this.value.set(defaultValue);
+        this.defaultValue = defaultValue;
     }
 
     @Override
-    public void reset() {}
+    public void reset() {
+        if (isDoReset()) {
+            value.set(defaultValue);
+        }
+    }
 
     @Override
     protected void updateSampleTime() {}
@@ -42,4 +52,22 @@ public long getStartTime() {
     public long getLastSampleTime() {
         return 0l;
     }
+
+    @Override
+    public T getValue() {
+        return value.get();
+    }
+
+    @Override
+    public void setValue(T value) {
+        if (isEnabled()) {
+            this.value.set(value); 
+        }
+    }
+
+    protected void appendFieldDescription(StringBuffer buffer) {
+        buffer.append(" value: ");
+        buffer.append(value.get());
+        super.appendFieldDescription(buffer);
+    }
 }

activemq-client/src/test/java/org/apache/activemq/management/UnsampledStatisticsTest.java

@@ -25,30 +25,36 @@
 public class UnsampledStatisticsTest {
 
     @Test
-    public void testUnsampledStatisticsEnabled() {
-        LongStatisticImpl longStatisticImpl = new LongStatisticImpl("longStat", "long", "A long statistic");
-        longStatisticImpl.setEnabled(true);
-        longStatisticImpl.setValue(Long.MAX_VALUE);
-        LongStatistic longStatistic = longStatisticImpl;
+    public void testUnsampledStatisticsEnabledTest() {
+        UnsampledStatisticImpl<Long> longStatistic = new UnsampledStatisticImpl<>("longStat", "long", "A long statistic", Long.valueOf(0l));
+        longStatistic.setEnabled(true);
+        longStatistic.setValue(Long.MAX_VALUE);
 
-        StringStatisticImpl stringStatisticImpl = new StringStatisticImpl("stringStat", "chars", "A string statistic");
-        stringStatisticImpl.setEnabled(true);
-        stringStatisticImpl.setValue("Hello World!");
-        StringStatistic stringStatistic = stringStatisticImpl;
+        UnsampledStatisticImpl<String> stringStatistic = new UnsampledStatisticImpl<>("stringStat", "chars", "A string statistic", null);
+        stringStatistic.setEnabled(true);
+        stringStatistic.setValue("Hello World!");
 
         assertEquals("A long statistic", longStatistic.getDescription());
         assertEquals(Long.valueOf(0l), Long.valueOf(longStatistic.getLastSampleTime()));
         assertEquals("longStat", longStatistic.getName());
         assertEquals(Long.valueOf(0l), Long.valueOf(longStatistic.getStartTime()));
         assertEquals("long", longStatistic.getUnit());
         assertEquals(Long.valueOf(Long.MAX_VALUE), longStatistic.getValue());
+        assertTrue(longStatistic.toString().contains("value: " + Long.MAX_VALUE));
+        longStatistic.reset();
+        assertEquals(Long.valueOf(0l), longStatistic.getValue());
+        assertTrue(longStatistic.toString().contains("value: 0"));
 
         assertEquals("A string statistic", stringStatistic.getDescription());
         assertEquals(Long.valueOf(0l), Long.valueOf(stringStatistic.getLastSampleTime()));
         assertEquals("stringStat", stringStatistic.getName());
         assertEquals(Long.valueOf(0l), Long.valueOf(stringStatistic.getStartTime()));
         assertEquals("chars", stringStatistic.getUnit());
         assertEquals("Hello World!", stringStatistic.getValue());
+        assertTrue(stringStatistic.toString().contains("value: Hello World!"));
+        stringStatistic.reset();
+        assertNull(stringStatistic.getValue());
+        assertTrue(stringStatistic.toString().contains("value: null"));
     }
 
 }