Refactor EventFactory into static methods. (#311)

* Remove EventFactory from Optimizely constructor.
* Remove ClientVersion and ClientEngine from OptimizelyBuilder
* Adds ClientEngineInfo for holding global engine value.
* Defines new UserEvent, ConversionEvent and ImpressionEvent models
* Redefines EventFactory to accept UserEvents via static methods
* Defines UserEventFactory to create UserEvents.

This change is in preparation for batching event payloads so we first want to extract separate canonical representations of conversions and impressions disjoint from the EventBatch model used for sending to the logging backend.

Author: Mike Davis

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

@@ -27,9 +27,8 @@
 import com.optimizely.ab.event.EventHandler;
 import com.optimizely.ab.event.LogEvent;
 import com.optimizely.ab.event.NoopEventHandler;
-import com.optimizely.ab.event.internal.BuildVersionInfo;
-import com.optimizely.ab.event.internal.EventFactory;
-import com.optimizely.ab.event.internal.payload.EventBatch.ClientEngine;
+import com.optimizely.ab.event.internal.*;
+import com.optimizely.ab.event.internal.payload.EventBatch;
 import com.optimizely.ab.notification.*;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -77,8 +76,6 @@ public class Optimizely implements AutoCloseable {
     @VisibleForTesting
     final DecisionService decisionService;
     @VisibleForTesting
-    final EventFactory eventFactory;
-    @VisibleForTesting
     final EventHandler eventHandler;
     @VisibleForTesting
     final ErrorHandler errorHandler;
@@ -92,17 +89,15 @@ public class Optimizely implements AutoCloseable {
     private final UserProfileService userProfileService;
 
     private Optimizely(@Nonnull EventHandler eventHandler,
-                       @Nonnull EventFactory eventFactory,
                        @Nonnull ErrorHandler errorHandler,
                        @Nonnull DecisionService decisionService,
                        @Nullable UserProfileService userProfileService,
                        @Nonnull ProjectConfigManager projectConfigManager,
                        @Nonnull NotificationCenter notificationCenter
     ) {
-        this.decisionService = decisionService;
         this.eventHandler = eventHandler;
-        this.eventFactory = eventFactory;
         this.errorHandler = errorHandler;
+        this.decisionService = decisionService;
         this.userProfileService = userProfileService;
         this.projectConfigManager = projectConfigManager;
         this.notificationCenter = notificationCenter;
@@ -230,36 +225,33 @@ private void sendImpression(@Nonnull ProjectConfig projectConfig,
                                 @Nonnull String userId,
                                 @Nonnull Map<String, ?> filteredAttributes,
                                 @Nonnull Variation variation) {
-        if (experiment.isRunning()) {
-            LogEvent impressionEvent = eventFactory.createImpressionEvent(
-                projectConfig,
-                experiment,
-                variation,
-                userId,
-                filteredAttributes);
-            logger.info("Activating user \"{}\" in experiment \"{}\".", userId, experiment.getKey());
+        if (!experiment.isRunning()) {
+            logger.info("Experiment has \"Launched\" status so not dispatching event during activation.");
+            return;
+        }
 
-            if (logger.isDebugEnabled()) {
-                logger.debug(
-                    "Dispatching impression event to URL {} with params {} and payload \"{}\".",
-                    impressionEvent.getEndpointUrl(), impressionEvent.getRequestParams(), impressionEvent.getBody());
-            }
+        logger.info("Activating user \"{}\" in experiment \"{}\".", userId, experiment.getKey());
+        UserEvent userEvent = UserEventFactory.createImpressionEvent(
+            projectConfig,
+            experiment,
+            variation,
+            userId,
+            filteredAttributes);
 
-            try {
-                eventHandler.dispatchEvent(impressionEvent);
-            } catch (Exception e) {
-                logger.error("Unexpected exception in event dispatcher", e);
-            }
+        LogEvent impressionEvent = EventFactory.createLogEvent(userEvent);
 
-            // Kept For backwards compatibility.
-            // This notification is deprecated and the new DecisionNotifications
-            // are sent via their respective method calls.
-            ActivateNotification activateNotification = new ActivateNotification(
-                experiment, userId, filteredAttributes, variation, impressionEvent);
-            notificationCenter.send(activateNotification);
-        } else {
-            logger.info("Experiment has \"Launched\" status so not dispatching event during activation.");
+        try {
+            eventHandler.dispatchEvent(impressionEvent);
+        } catch (Exception e) {
+            logger.error("Unexpected exception in event dispatcher", e);
         }
+
+        // Kept For backwards compatibility.
+        // This notification is deprecated and the new DecisionNotifications
+        // are sent via their respective method calls.
+        ActivateNotification activateNotification = new ActivateNotification(
+            experiment, userId, filteredAttributes, variation, impressionEvent);
+        notificationCenter.send(activateNotification);
     }
 
     //======== track calls ========//
@@ -309,22 +301,18 @@ public void track(@Nonnull String eventName,
             logger.warn("Event tags is null when non-null was expected. Defaulting to an empty event tags map.");
         }
 
-        // create the conversion event request parameters, then dispatch
-        LogEvent conversionEvent = eventFactory.createConversionEvent(
+        UserEvent userEvent = UserEventFactory.createConversionEvent(
             projectConfig,
             userId,
             eventType.getId(),
             eventType.getKey(),
             copiedAttributes,
             eventTags);
 
+        // create the conversion event request parameters, then dispatch
+        LogEvent conversionEvent = EventFactory.createLogEvent(userEvent);
         logger.info("Tracking event \"{}\" for user \"{}\".", eventName, userId);
 
-        if (logger.isDebugEnabled()) {
-            logger.debug("Dispatching conversion event to URL {} with params {} and payload \"{}\".",
-                conversionEvent.getEndpointUrl(), conversionEvent.getRequestParams(), conversionEvent.getBody());
-        }
-
         try {
             eventHandler.dispatchEvent(conversionEvent);
         } catch (Exception e) {
@@ -1012,9 +1000,6 @@ public static class Builder {
         private DecisionService decisionService;
         private ErrorHandler errorHandler;
         private EventHandler eventHandler;
-        private EventFactory eventFactory;
-        private ClientEngine clientEngine;
-        private String clientVersion;
         private ProjectConfig projectConfig;
         private ProjectConfigManager projectConfigManager;
         private UserProfileService userProfileService;
@@ -1047,13 +1032,16 @@ public Builder withUserProfileService(UserProfileService userProfileService) {
             return this;
         }
 
-        public Builder withClientEngine(ClientEngine clientEngine) {
-            this.clientEngine = clientEngine;
+        @Deprecated
+        public Builder withClientEngine(EventBatch.ClientEngine clientEngine) {
+            logger.info("Deprecated. In the future, set ClientEngine via ClientEngineInfo#setClientEngine.");
+            ClientEngineInfo.setClientEngine(clientEngine);
             return this;
         }
 
+        @Deprecated
         public Builder withClientVersion(String clientVersion) {
-            this.clientVersion = clientVersion;
+            logger.info("Explicitly setting the ClientVersion is no longer supported.");
             return this;
         }
 
@@ -1090,18 +1078,6 @@ protected Builder withDecisionService(DecisionService decisionService) {
 
         public Optimizely build() {
 
-            if (clientEngine == null) {
-                clientEngine = ClientEngine.JAVA_SDK;
-            }
-
-            if (clientVersion == null) {
-                clientVersion = BuildVersionInfo.VERSION;
-            }
-
-            if (eventFactory == null) {
-                eventFactory = new EventFactory(clientEngine, clientVersion);
-            }
-
             if (errorHandler == null) {
                 errorHandler = new NoOpErrorHandler();
             }
@@ -1141,7 +1117,7 @@ public Optimizely build() {
                 notificationCenter = new NotificationCenter();
             }
 
-            return new Optimizely(eventHandler, eventFactory, errorHandler, decisionService, userProfileService, projectConfigManager, notificationCenter);
+            return new Optimizely(eventHandler, errorHandler, decisionService, userProfileService, projectConfigManager, notificationCenter);
         }
     }
 }

core-api/src/main/java/com/optimizely/ab/config/Experiment.java

@@ -17,6 +17,7 @@
 package com.optimizely.ab.config;
 
 import com.fasterxml.jackson.annotation.*;
+import com.optimizely.ab.annotations.VisibleForTesting;
 import com.optimizely.ab.config.audience.AudienceIdCondition;
 import com.optimizely.ab.config.audience.Condition;
 
@@ -69,6 +70,11 @@ public String toString() {
         }
     }
 
+    @VisibleForTesting
+    public Experiment(String id, String key, String layerId) {
+        this(id, key, null, layerId, Collections.emptyList(), null, Collections.emptyList(), Collections.emptyMap(), Collections.emptyList(), "");
+    }
+
     @JsonCreator
     public Experiment(@JsonProperty("id") String id,
                       @JsonProperty("key") String key,

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

@@ -0,0 +1,36 @@
+/**
+ *
+ *    Copyright 2019, Optimizely and contributors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package com.optimizely.ab.event.internal;
+
+import java.util.UUID;
+
+/**
+ * BaseEvent provides a GUID implementation along with a system timestamp.
+ */
+public class BaseEvent {
+
+    private final String uuid = UUID.randomUUID().toString();
+    private final long timestamp = System.currentTimeMillis();
+
+    public final String getUUID() {
+        return uuid;
+    }
+
+    public final long getTimestamp() {
+        return timestamp;
+    }
+}

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

@@ -0,0 +1,50 @@
+/**
+ *
+ *    Copyright 2019, Optimizely and contributors
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package com.optimizely.ab.event.internal;
+
+import com.optimizely.ab.event.internal.payload.EventBatch;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * ClientEngineInfo is a utility to globally get and set the ClientEngine used in
+ * event tracking. The ClientEngine defaults to JAVA_SDK but can be overridden at
+ * runtime.
+ */
+public class ClientEngineInfo {
+    private static final Logger logger = LoggerFactory.getLogger(ClientEngineInfo.class);
+
+    public static final EventBatch.ClientEngine DEFAULT = EventBatch.ClientEngine.JAVA_SDK;
+    private static EventBatch.ClientEngine clientEngine = DEFAULT;
+
+    public static void setClientEngine(EventBatch.ClientEngine clientEngine) {
+        if (clientEngine == null) {
+            logger.warn("ClientEngine cannot be null, defaulting to {}", ClientEngineInfo.clientEngine.getClientEngineValue());
+            return;
+        }
+
+        logger.info("Setting Optimizely client engine to {}", clientEngine.getClientEngineValue());
+        ClientEngineInfo.clientEngine = clientEngine;
+    }
+
+    public static EventBatch.ClientEngine getClientEngine() {
+        return clientEngine;
+    }
+
+    private ClientEngineInfo() {
+    }
+}