Move serialization to LogEvent.getBody(). (#201)

This PR moves the serialization from POJO to JSON into LogEvent#getBody(). This allows the serialization of the event to be offloaded to with the event handler when the HTTP request is built. This should be 100% backwards compatible with any existing EventHandler implementations. Initial benchmarks are much improved over the current master in tight loop simulations.

Author: Mike Davis

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

@@ -199,9 +199,13 @@ private void sendImpression(@Nonnull ProjectConfig projectConfig,
                     userId,
                     filteredAttributes);
             logger.info("Activating user \"{}\" in experiment \"{}\".", userId, experiment.getKey());
-            logger.debug(
-                    "Dispatching impression event to URL {} with params {} and payload \"{}\".",
-                    impressionEvent.getEndpointUrl(), impressionEvent.getRequestParams(), impressionEvent.getBody());
+
+            if (logger.isDebugEnabled()) {
+                logger.debug(
+                        "Dispatching impression event to URL {} with params {} and payload \"{}\".",
+                        impressionEvent.getEndpointUrl(), impressionEvent.getRequestParams(), impressionEvent.getBody());
+            }
+
             try {
                 eventHandler.dispatchEvent(impressionEvent);
             } catch (Exception e) {
@@ -294,8 +298,12 @@ public void track(@Nonnull String eventName,
         }
 
         logger.info("Tracking event \"{}\" for user \"{}\".", eventName, userId);
-        logger.debug("Dispatching conversion event to URL {} with params {} and payload \"{}\".",
-                conversionEvent.getEndpointUrl(), conversionEvent.getRequestParams(), conversionEvent.getBody());
+
+        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) {

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

@@ -16,6 +16,10 @@
  */
 package com.optimizely.ab.event;
 
+import com.optimizely.ab.event.internal.payload.EventBatch;
+import com.optimizely.ab.event.internal.serializer.DefaultJsonSerializer;
+import com.optimizely.ab.event.internal.serializer.Serializer;
+
 import java.util.Map;
 
 import javax.annotation.Nonnull;
@@ -30,16 +34,16 @@ public class LogEvent {
     private final RequestMethod requestMethod;
     private final String endpointUrl;
     private final Map<String, String> requestParams;
-    private final String body;
+    private final EventBatch eventBatch;
 
     public LogEvent(@Nonnull RequestMethod requestMethod,
                     @Nonnull String endpointUrl,
                     @Nonnull Map<String, String> requestParams,
-                    @Nonnull String body) {
+                    EventBatch eventBatch) {
         this.requestMethod = requestMethod;
         this.endpointUrl = endpointUrl;
         this.requestParams = requestParams;
-        this.body = body;
+        this.eventBatch = eventBatch;
     }
 
     //======== Getters ========//
@@ -57,7 +61,12 @@ public Map<String, String> getRequestParams() {
     }
 
     public String getBody() {
-        return body;
+        if (eventBatch == null) {
+            return "";
+        }
+
+        Serializer serializer = DefaultJsonSerializer.getInstance();
+        return serializer.serialize(eventBatch);
     }
 
     //======== Overriding method ========//
@@ -68,7 +77,7 @@ public String toString() {
                "requestMethod=" + requestMethod +
                ", endpointUrl='" + endpointUrl + '\'' +
                ", requestParams=" + requestParams +
-               ", body='" + body + '\'' +
+               ", body='" + getBody() + '\'' +
                '}';
     }
 

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

@@ -28,8 +28,6 @@
 import com.optimizely.ab.event.internal.payload.Event;
 import com.optimizely.ab.event.internal.payload.Snapshot;
 import com.optimizely.ab.event.internal.payload.Visitor;
-import com.optimizely.ab.event.internal.serializer.DefaultJsonSerializer;
-import com.optimizely.ab.event.internal.serializer.Serializer;
 import com.optimizely.ab.internal.EventTagUtils;
 import com.optimizely.ab.internal.ControlAttribute;
 import org.slf4j.Logger;
@@ -46,7 +44,6 @@ public class EventFactory {
     static final String EVENT_ENDPOINT = "https://logx.optimizely.com/v1/events";  // Should be part of the datafile
     static final String  ACTIVATE_EVENT_KEY = "campaign_activated";
 
-    private Serializer serializer;
     @VisibleForTesting
     public final String clientVersion;
     @VisibleForTesting
@@ -59,7 +56,6 @@ public EventFactory() {
     public EventFactory(EventBatch.ClientEngine clientEngine, String clientVersion) {
         this.clientEngine = clientEngine;
         this.clientVersion = clientVersion;
-        this.serializer = DefaultJsonSerializer.getInstance();
     }
 
     public LogEvent createImpressionEvent(@Nonnull ProjectConfig projectConfig,
@@ -104,8 +100,7 @@ public LogEvent createImpressionEvent(@Nonnull ProjectConfig projectConfig,
                 .setRevision(projectConfig.getRevision())
                 .build();
 
-        String payload = this.serializer.serialize(eventBatch);
-        return new LogEvent(LogEvent.RequestMethod.POST, EVENT_ENDPOINT, Collections.<String, String>emptyMap(), payload);
+        return new LogEvent(LogEvent.RequestMethod.POST, EVENT_ENDPOINT, Collections.<String, String>emptyMap(), eventBatch);
     }
 
     public LogEvent createConversionEvent(@Nonnull ProjectConfig projectConfig,
@@ -166,8 +161,7 @@ public LogEvent createConversionEvent(@Nonnull ProjectConfig projectConfig,
                 .setRevision(projectConfig.getRevision())
                 .build();
 
-        String payload = this.serializer.serialize(eventBatch);
-        return new LogEvent(LogEvent.RequestMethod.POST, EVENT_ENDPOINT, Collections.<String, String>emptyMap(), payload);
+        return new LogEvent(LogEvent.RequestMethod.POST, EVENT_ENDPOINT, Collections.<String, String>emptyMap(), eventBatch);
     }
 
     private List<Attribute> buildAttributeList(ProjectConfig projectConfig, Map<String, String> attributes) {