(feat): Feature Management isFeatureEnabled Listener (#271)

Author: mnoman09

core-api/src/main/java/com/optimizely/ab/Optimizely.java

@@ -387,8 +387,12 @@ public Boolean isFeatureEnabled(@Nonnull String featureKey,
         }
 
         Map<String, ?> copiedAttributes = copyAttributes(attributes);
-        FeatureDecision featureDecision = decisionService.getVariationForFeature(featureFlag, userId, copiedAttributes);
+        FeatureDecision.DecisionSource decisionSource = FeatureDecision.DecisionSource.ROLLOUT;
+        String sourceExperimentKey = null;
+        String sourceVariationKey = null;
 
+        FeatureDecision featureDecision = decisionService.getVariationForFeature(featureFlag, userId, copiedAttributes);
+        Boolean featureEnabled = false;
         if (featureDecision.variation != null) {
             if (featureDecision.decisionSource.equals(FeatureDecision.DecisionSource.FEATURE_TEST)) {
                 sendImpression(
@@ -397,18 +401,32 @@ public Boolean isFeatureEnabled(@Nonnull String featureKey,
                     userId,
                     copiedAttributes,
                     featureDecision.variation);
+                decisionSource = featureDecision.decisionSource;
+                sourceVariationKey = featureDecision.variation.getKey();
+                sourceExperimentKey = featureDecision.experiment.getKey();
             } else {
                 logger.info("The user \"{}\" is not included in an experiment for feature \"{}\".",
                     userId, featureKey);
             }
             if (featureDecision.variation.getFeatureEnabled()) {
                 logger.info("Feature \"{}\" is enabled for user \"{}\".", featureKey, userId);
-                return true;
+                featureEnabled = true;
             }
         }
 
+        DecisionNotification decisionNotification = DecisionNotification.newFeatureDecisionNotificationBuilder()
+            .withUserId(userId)
+            .withAttributes(copiedAttributes)
+            .withFeatureKey(featureKey)
+            .withFeatureEnabled(featureEnabled)
+            .withSource(decisionSource)
+            .withExperimentKey(sourceExperimentKey)
+            .withVariationKey(sourceVariationKey)
+            .build();
+        notificationCenter.sendNotifications(decisionNotification);
+
         logger.info("Feature \"{}\" is not enabled for user \"{}\".", featureKey, userId);
-        return false;
+        return featureEnabled;
     }
 
     /**

core-api/src/main/java/com/optimizely/ab/notification/DecisionNotification.java

@@ -16,9 +16,7 @@
 
 package com.optimizely.ab.notification;
 
-
 import com.optimizely.ab.bucketing.FeatureDecision;
-import com.optimizely.ab.config.FeatureVariable;
 import com.optimizely.ab.config.Variation;
 
 import javax.annotation.Nonnull;
@@ -69,8 +67,8 @@ public static ExperimentDecisionNotificationBuilder newExperimentDecisionNotific
     }
 
     public static class ExperimentDecisionNotificationBuilder {
-        public final static String EXPERIMENT_KEY = "experiment_key";
-        public final static String VARIATION_KEY = "variation_key";
+        public final static String EXPERIMENT_KEY = "experimentKey";
+        public final static String VARIATION_KEY = "variationKey";
 
         private String type;
         private String experimentKey;
@@ -116,4 +114,81 @@ public DecisionNotification build() {
                 decisionInfo);
         }
     }
+
+    public static FeatureDecisionNotificationBuilder newFeatureDecisionNotificationBuilder() {
+        return new FeatureDecisionNotificationBuilder();
+    }
+
+    public static class FeatureDecisionNotificationBuilder {
+        public final static String FEATURE_KEY = "featureKey";
+        public final static String FEATURE_ENABLED = "featureEnabled";
+        public final static String SOURCE = "source";
+        public final static String SOURCE_INFO = "sourceInfo";
+        public final static String EXPERIMENT_KEY = "experimentKey";
+        public final static String VARIATION_KEY = "variationKey";
+
+        private String featureKey;
+        private Boolean featureEnabled;
+        private String experimentKey;
+        private String variationKey;
+        private FeatureDecision.DecisionSource source;
+        private String userId;
+        private Map<String, ?> attributes;
+        private Map<String, Object> decisionInfo;
+
+        public FeatureDecisionNotificationBuilder withUserId(String userId) {
+            this.userId = userId;
+            return this;
+        }
+
+        public FeatureDecisionNotificationBuilder withAttributes(Map<String, ?> attributes) {
+            this.attributes = attributes;
+            return this;
+        }
+
+        public FeatureDecisionNotificationBuilder withExperimentKey(String experimentKey) {
+            this.experimentKey = experimentKey;
+            return this;
+        }
+
+        public FeatureDecisionNotificationBuilder withVariationKey(String variationKey) {
+            this.variationKey = variationKey;
+            return this;
+        }
+
+        public FeatureDecisionNotificationBuilder withSource(FeatureDecision.DecisionSource source) {
+            this.source = source;
+            return this;
+        }
+
+        public FeatureDecisionNotificationBuilder withFeatureKey(String featureKey) {
+            this.featureKey = featureKey;
+            return this;
+        }
+
+        public FeatureDecisionNotificationBuilder withFeatureEnabled(Boolean featureEnabled) {
+            this.featureEnabled = featureEnabled;
+            return this;
+        }
+
+        public DecisionNotification build() {
+            decisionInfo = new HashMap<>();
+            decisionInfo.put(FEATURE_KEY, featureKey);
+            decisionInfo.put(FEATURE_ENABLED, featureEnabled);
+            decisionInfo.put(SOURCE, source);
+
+            Map<String, String> sourceInfo = new HashMap<>();
+            if (source.equals(FeatureDecision.DecisionSource.FEATURE_TEST)) {
+                sourceInfo.put(EXPERIMENT_KEY, experimentKey);
+                sourceInfo.put(VARIATION_KEY, variationKey);
+            }
+            decisionInfo.put(SOURCE_INFO, sourceInfo);
+
+            return new DecisionNotification(
+                NotificationCenter.DecisionNotificationType.FEATURE.toString(),
+                userId,
+                attributes,
+                decisionInfo);
+        }
+    }
 }