Add OptimizelyFactory and update config notification. (#298)

* Add UpdateConfigNotification
* Add NotificationCenter to builder.
* Create OptimizelyFactory for basic default configurability.
* Add PropertyUtils to standardize on default overrides by environment.

Author: Mike Davis

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

@@ -85,7 +85,8 @@ public class Optimizely implements AutoCloseable {
 
     private final ProjectConfigManager projectConfigManager;
 
-    public final NotificationCenter notificationCenter = new NotificationCenter();
+    // TODO should be private
+    public final NotificationCenter notificationCenter;
 
     @Nullable
     private final UserProfileService userProfileService;
@@ -94,15 +95,17 @@ private Optimizely(@Nonnull EventHandler eventHandler,
                        @Nonnull EventFactory eventFactory,
                        @Nonnull ErrorHandler errorHandler,
                        @Nonnull DecisionService decisionService,
-                       @Nonnull UserProfileService userProfileService,
-                       @Nonnull ProjectConfigManager projectConfigManager
+                       @Nullable UserProfileService userProfileService,
+                       @Nonnull ProjectConfigManager projectConfigManager,
+                       @Nonnull NotificationCenter notificationCenter
     ) {
         this.decisionService = decisionService;
         this.eventHandler = eventHandler;
         this.eventFactory = eventFactory;
         this.errorHandler = errorHandler;
         this.userProfileService = userProfileService;
         this.projectConfigManager = projectConfigManager;
+        this.notificationCenter = notificationCenter;
     }
 
     /**
@@ -951,17 +954,34 @@ public NotificationCenter getNotificationCenter() {
      * Convenience method for adding DecisionNotification Handlers
      */
     public int addDecisionNotificationHandler(NotificationHandler<DecisionNotification> handler) {
-        NotificationManager<DecisionNotification> manager = notificationCenter
-            .getNotificationManager(DecisionNotification.class);
-        return manager.addHandler(handler);
+        return addNotificationHandler(DecisionNotification.class, handler);
     }
 
     /**
      * Convenience method for adding TrackNotification Handlers
      */
     public int addTrackNotificationHandler(NotificationHandler<TrackNotification> handler) {
-        NotificationManager<TrackNotification> notificationManager =
-            notificationCenter.getNotificationManager(TrackNotification.class);
+        return addNotificationHandler(TrackNotification.class, handler);
+    }
+
+    /**
+     * Convenience method for adding UpdateConfigNotification Handlers
+     */
+    public int addUpdateConfigNotificationHandler(NotificationHandler<UpdateConfigNotification> handler) {
+        return addNotificationHandler(UpdateConfigNotification.class, handler);
+    }
+
+    /**
+     * Convenience method for adding UpdateConfigNotification Handlers
+     */
+    private <T> int addNotificationHandler(Class<T> clazz, NotificationHandler<T> handler) {
+        NotificationManager<T> notificationManager = notificationCenter.getNotificationManager(clazz);
+
+        if (notificationManager == null) {
+            logger.warn("{} not supported by the NotificationCenter.", clazz);
+            return -1;
+        }
+
         return notificationManager.addHandler(handler);
     }
 
@@ -999,6 +1019,7 @@ public static class Builder {
         private ProjectConfig projectConfig;
         private ProjectConfigManager projectConfigManager;
         private UserProfileService userProfileService;
+        private NotificationCenter notificationCenter;
 
         // For backwards compatibility
         private AtomicProjectConfigManager fallbackConfigManager = new AtomicProjectConfigManager();
@@ -1063,6 +1084,11 @@ protected Builder withEventBuilder(EventFactory eventFactory) {
             return this;
         }
 
+        protected Builder withNotificationCenter(NotificationCenter notificationCenter) {
+            this.notificationCenter = notificationCenter;
+            return this;
+        }
+
         public Optimizely build() {
 
             if (clientEngine == null) {
@@ -1112,7 +1138,11 @@ public Optimizely build() {
                 projectConfigManager = fallbackConfigManager;
             }
 
-            return new Optimizely(eventHandler, eventFactory, errorHandler, decisionService, userProfileService, projectConfigManager);
+            if (notificationCenter == null) {
+                notificationCenter = new NotificationCenter();
+            }
+
+            return new Optimizely(eventHandler, eventFactory, errorHandler, decisionService, userProfileService, projectConfigManager, notificationCenter);
         }
     }
 }

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

@@ -16,6 +16,8 @@
  */
 package com.optimizely.ab.config;
 
+import com.optimizely.ab.notification.NotificationCenter;
+import com.optimizely.ab.notification.UpdateConfigNotification;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -38,27 +40,35 @@
 public abstract class PollingProjectConfigManager implements ProjectConfigManager, AutoCloseable {
 
     private static final Logger logger = LoggerFactory.getLogger(PollingProjectConfigManager.class);
+    private static final UpdateConfigNotification SIGNAL = new UpdateConfigNotification();
 
     private final AtomicReference<ProjectConfig> currentProjectConfig = new AtomicReference<>();
     private final ScheduledExecutorService scheduledExecutorService;
     private final long period;
     private final TimeUnit timeUnit;
     private final long blockingTimeoutPeriod;
     private final TimeUnit blockingTimeoutUnit;
+    private final NotificationCenter notificationCenter;
+
     private final CountDownLatch countDownLatch = new CountDownLatch(1);
 
     private volatile boolean started;
     private ScheduledFuture<?> scheduledFuture;
 
     public PollingProjectConfigManager(long period, TimeUnit timeUnit)  {
-        this(period, timeUnit, Long.MAX_VALUE, TimeUnit.MILLISECONDS);
+        this(period, timeUnit, Long.MAX_VALUE, TimeUnit.MILLISECONDS, new NotificationCenter());
+    }
+
+    public PollingProjectConfigManager(long period, TimeUnit timeUnit, NotificationCenter notificationCenter)  {
+        this(period, timeUnit, Long.MAX_VALUE, TimeUnit.MILLISECONDS, notificationCenter);
     }
 
-    public PollingProjectConfigManager(long period, TimeUnit timeUnit, long blockingTimeoutPeriod, TimeUnit blockingTimeoutUnit)  {
+    public PollingProjectConfigManager(long period, TimeUnit timeUnit, long blockingTimeoutPeriod, TimeUnit blockingTimeoutUnit, NotificationCenter notificationCenter)  {
         this.period = period;
         this.timeUnit = timeUnit;
         this.blockingTimeoutPeriod = blockingTimeoutPeriod;
         this.blockingTimeoutUnit = blockingTimeoutUnit;
+        this.notificationCenter = notificationCenter;
 
         final ThreadFactory threadFactory = Executors.defaultThreadFactory();
         this.scheduledExecutorService = Executors.newSingleThreadScheduledExecutor(runnable -> {
@@ -89,9 +99,14 @@ void setConfig(ProjectConfig projectConfig) {
         logger.info("New datafile set with revision: {}. Old revision: {}", projectConfig.getRevision(), previousRevision);
 
         currentProjectConfig.set(projectConfig);
+        notificationCenter.send(SIGNAL);
         countDownLatch.countDown();
     }
 
+    public NotificationCenter getNotificationCenter() {
+        return notificationCenter;
+    }
+
     /**
      * If the instance was never started, then call getConfig() directly from the inner ProjectConfigManager.
      * else, wait until the ProjectConfig is set or the timeout expires.