Add support for numeric metrics (#129)

Author: Vignesh Raja

core-api/src/main/java/com/optimizely/ab/event/internal/EventBuilderV2.java

@@ -112,10 +112,16 @@ public LogEvent createConversionEvent(@Nonnull ProjectConfig projectConfig,
 
         List<LayerState> layerStates = createLayerStates(projectConfig, experimentVariationMap);
 
-        Long eventValue = EventTagUtils.getRevenueValue(eventTags);
-        List<EventMetric> eventMetrics = Collections.emptyList();
-        if (eventValue != null) {
-            eventMetrics = Collections.singletonList(new EventMetric(EventMetric.REVENUE_METRIC_TYPE, eventValue));
+        List<EventMetric> eventMetrics = new ArrayList<EventMetric>();
+
+        Long revenueValue = EventTagUtils.getRevenueValue(eventTags);
+        if (revenueValue != null) {
+            eventMetrics.add(new EventMetric(EventMetric.REVENUE_METRIC_TYPE, revenueValue));
+        }
+
+        Double numericMetricValue = EventTagUtils.getNumericValue(eventTags);
+        if (numericMetricValue != null) {
+            eventMetrics.add(new EventMetric(EventMetric.NUMERIC_METRIC_TYPE, numericMetricValue));
         }
 
         Conversion conversionPayload = new Conversion();

core-api/src/main/java/com/optimizely/ab/event/internal/payload/EventMetric.java

@@ -19,13 +19,14 @@
 public class EventMetric {
 
     public static final String REVENUE_METRIC_TYPE = "revenue";
+    public static final String NUMERIC_METRIC_TYPE = "value";
 
     private String name;
-    private long value;
+    private Number value;
 
     public EventMetric() { }
 
-    public EventMetric(String name, long value) {
+    public EventMetric(String name, Number value) {
         this.name = name;
         this.value = value;
     }
@@ -38,30 +39,29 @@ public void setName(String name) {
         this.name = name;
     }
 
-    public long getValue() {
+    public Number getValue() {
         return value;
     }
 
-    public void setValue(long value) {
+    public void setValue(Number value) {
         this.value = value;
     }
 
-
     @Override
-    public boolean equals(Object other) {
-        if (!(other instanceof EventMetric))
-            return false;
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (obj == null || getClass() != obj.getClass()) return false;
 
-        EventMetric otherEventMetric = (EventMetric)other;
+        EventMetric that = (EventMetric) obj;
 
-        return name.equals(otherEventMetric.getName()) && value == otherEventMetric.getValue();
+        if (!name.equals(that.name)) return false;
+        return value.equals(that.value);
     }
 
-
     @Override
     public int hashCode() {
-        int result = name != null ? name.hashCode() : 0;
-        result = 31 * result + (int) (value ^ (value >>> 32));
+        int result = name.hashCode();
+        result = 31 * result + value.hashCode();
         return result;
     }
 

core-api/src/main/java/com/optimizely/ab/internal/EventTagUtils.java

@@ -47,4 +47,22 @@ public static Long getRevenueValue(@Nonnull Map<String, ?> eventTags) {
         }
         return eventValue;
     }
+
+    /**
+     * Fetch the numeric metric value from event tags. "value" is a reserved keyword.
+     */
+    public static Double getNumericValue(@Nonnull Map<String, ?> eventTags) {
+        Double eventValue = null;
+        if (eventTags.containsKey(ReservedEventKey.VALUE.toString())) {
+            Object rawValue = eventTags.get(ReservedEventKey.VALUE.toString());
+            if (rawValue instanceof Number) {
+                eventValue = ((Number) rawValue).doubleValue();
+                logger.info("Parsed numeric metric value \"{}\" from event tags.", eventValue);
+            } else {
+                logger.warn("Failed to parse numeric metric value \"{}\" from event tags.", rawValue);
+            }
+        }
+
+        return eventValue;
+    }
 }

core-api/src/main/java/com/optimizely/ab/internal/ReservedEventKey.java

@@ -17,7 +17,8 @@
 package com.optimizely.ab.internal;
 
 public enum ReservedEventKey {
-    REVENUE("revenue");
+    REVENUE("revenue"),
+    VALUE("value");
 
     private final String key;
 

core-api/src/test/java/com/optimizely/ab/event/internal/EventBuilderV2Test.java

@@ -17,6 +17,7 @@
 package com.optimizely.ab.event.internal;
 
 import com.google.gson.Gson;
+import com.google.gson.internal.LazilyParsedNumber;
 import com.optimizely.ab.bucketing.Bucketer;
 import com.optimizely.ab.bucketing.DecisionService;
 import com.optimizely.ab.bucketing.UserProfileService;
@@ -314,11 +315,13 @@ public void createConversionEvent() throws Exception {
     }
 
     /**
-     * Verify that eventValue is properly recorded in a conversion request as an {@link EventMetric}
+     * Verify that "revenue" and "value" are properly recorded in a conversion request as {@link EventMetric} objects.
+     * "revenue" is fixed-point and "value" is floating-point.
      */
     @Test
-    public void createConversionParamsWithRevenue() throws Exception {
-        long revenue = 1234L;
+    public void createConversionParamsWithEventMetrics() throws Exception {
+        Long revenue = 1234L;
+        Double value = 13.37;
 
         // use the "valid" project config and its associated experiment, variation, and attributes
         Attribute attribute = validProjectConfig.getAttributes().get(0);
@@ -341,6 +344,7 @@ public void createConversionParamsWithRevenue() throws Exception {
         Map<String, String> attributeMap = Collections.singletonMap(attribute.getKey(), "value");
         Map<String, Object> eventTagMap = new HashMap<String, Object>();
         eventTagMap.put(ReservedEventKey.REVENUE.toString(), revenue);
+        eventTagMap.put(ReservedEventKey.VALUE.toString(), value);
         Map<Experiment, Variation> experimentVariationMap = createExperimentVariationMap(
                 validProjectConfig,
                 decisionService,
@@ -352,10 +356,11 @@ public void createConversionParamsWithRevenue() throws Exception {
                 eventTagMap);
 
         Conversion conversion = gson.fromJson(conversionEvent.getBody(), Conversion.class);
-
-        // we're not going to verify everything, only revenue
-        assertThat(conversion.getEventMetrics(),
-                is(Collections.singletonList(new EventMetric(EventMetric.REVENUE_METRIC_TYPE, revenue))));
+        List<EventMetric> eventMetrics = Arrays.asList(
+                new EventMetric(EventMetric.REVENUE_METRIC_TYPE, new LazilyParsedNumber(revenue.toString())),
+                new EventMetric(EventMetric.NUMERIC_METRIC_TYPE, new LazilyParsedNumber(value.toString())));
+        // we're not going to verify everything, only the event metrics
+        assertThat(conversion.getEventMetrics(), is(eventMetrics));
     }
 
     /**