Extract EngagementManager and cover it with unit tests

parsely/src/main/java/com/parsely/parselyandroid/EngagementManager.java

@@ -0,0 +1,120 @@
+package com.parsely.parselyandroid;
+
+import java.util.Calendar;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.TimeZone;
+import java.util.Timer;
+import java.util.TimerTask;
+
+/**
+ * Engagement manager for article and video engagement.
+ * <p>
+ * Implemented to handle its own queuing of future executions to accomplish
+ * two things:
+ * <p>
+ * 1. Flushing any engaged time before canceling.
+ * 2. Progressive backoff for long engagements to save data.
+ */
+class EngagementManager {
+
+    private final ParselyTracker parselyTracker;
+    public Map<String, Object> baseEvent;
+    private boolean started;
+    private final Timer parentTimer;
+    private TimerTask waitingTimerTask;
+    private long latestDelayMillis, totalTime;
+    private Calendar startTime;
+    private final UpdateEngagementIntervalCalculator intervalCalculator;
+
+    public EngagementManager(
+            ParselyTracker parselyTracker,
+            Timer parentTimer,
+            long intervalMillis,
+            Map<String, Object> baseEvent,
+            UpdateEngagementIntervalCalculator intervalCalculator
+    ) {
+        this.parselyTracker = parselyTracker;
+        this.baseEvent = baseEvent;
+        this.parentTimer = parentTimer;
+        this.intervalCalculator = intervalCalculator;
+        latestDelayMillis = intervalMillis;
+        totalTime = 0;
+        startTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+    }
+
+    public boolean isRunning() {
+        return started;
+    }
+
+    public void start() {
+        scheduleNextExecution(latestDelayMillis);
+        started = true;
+        startTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+    }
+
+    public void stop() {
+        waitingTimerTask.cancel();
+        started = false;
+    }
+
+    public boolean isSameVideo(String url, String urlRef, ParselyVideoMetadata metadata) {
+        Map<String, Object> baseMetadata = (Map<String, Object>) baseEvent.get("metadata");
+        return (baseEvent.get("url").equals(url) &&
+                baseEvent.get("urlref").equals(urlRef) &&
+                baseMetadata.get("link").equals(metadata.link) &&
+                (int) (baseMetadata.get("duration")) == metadata.durationSeconds);
+    }
+
+    private void scheduleNextExecution(long delay) {
+        TimerTask task = new TimerTask() {
+            public void run() {
+                doEnqueue(scheduledExecutionTime());
+                latestDelayMillis = intervalCalculator.updateLatestInterval(startTime);
+                scheduleNextExecution(latestDelayMillis);
+            }
+
+            public boolean cancel() {
+                boolean output = super.cancel();
+                // Only enqueue when we actually canceled something. If output is false then
+                // this has already been canceled.
+                if (output) {
+                    doEnqueue(scheduledExecutionTime());
+                }
+                return output;
+            }
+        };
+        latestDelayMillis = delay;
+        parentTimer.schedule(task, delay);
+        waitingTimerTask = task;
+    }
+
+    private void doEnqueue(long scheduledExecutionTime) {
+        // Create a copy of the base event to enqueue
+        Map<String, Object> event = new HashMap<>(baseEvent);
+        ParselyTracker.PLog(String.format("Enqueuing %s event.", event.get("action")));
+
+        // Update `ts` for the event since it's happening right now.
+        Calendar now = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+        @SuppressWarnings("unchecked")
+        Map<String, Object> baseEventData = (Map<String, Object>) event.get("data");
+        assert baseEventData != null;
+        Map<String, Object> data = new HashMap<>(baseEventData);
+        data.put("ts", now.getTimeInMillis());
+        event.put("data", data);
+
+        // Adjust inc by execution time in case we're late or early.
+        long executionDiff = (System.currentTimeMillis() - scheduledExecutionTime);
+        long inc = (latestDelayMillis + executionDiff);
+        totalTime += inc;
+        event.put("inc", inc / 1000);
+        event.put("tt", totalTime);
+
+        parselyTracker.enqueueEvent(event);
+    }
+
+
+    public double getIntervalMillis() {
+        return latestDelayMillis;
+    }
+}

parsely/src/main/java/com/parsely/parselyandroid/ParselyTracker.java

@@ -38,12 +38,10 @@
 import java.io.ObjectOutputStream;
 import java.io.StringWriter;
 import java.util.ArrayList;
-import java.util.Calendar;
 import java.util.Formatter;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
-import java.util.TimeZone;
 import java.util.Timer;
 import java.util.TimerTask;
 import java.util.UUID;
@@ -74,6 +72,7 @@ public class ParselyTracker {
     private String lastPageviewUuid = null;
     @NonNull
     private final EventsBuilder eventsBuilder;
+    @NonNull final UpdateEngagementIntervalCalculator intervalCalculator = new UpdateEngagementIntervalCalculator();
 
     /**
      * Create a new ParselyTracker instance.
@@ -176,7 +175,7 @@ public double getVideoEngagementInterval() {
      * @return Whether the engagement tracker is running.
      */
     public boolean engagementIsActive() {
-        return engagementManager != null && engagementManager.started;
+        return engagementManager != null && engagementManager.isRunning();
     }
 
     /**
@@ -185,7 +184,7 @@ public boolean engagementIsActive() {
      * @return Whether video tracking is active.
      */
     public boolean videoIsActive() {
-        return videoEngagementManager != null && videoEngagementManager.started;
+        return videoEngagementManager != null && videoEngagementManager.isRunning();
     }
 
     /**
@@ -289,7 +288,7 @@ public void startEngagement(
 
         // Start a new EngagementTask
         Map<String, Object> event = eventsBuilder.buildEvent(url, urlRef, "heartbeat", null, extraData, lastPageviewUuid);
-        engagementManager = new EngagementManager(timer, DEFAULT_ENGAGEMENT_INTERVAL_MILLIS, event);
+        engagementManager = new EngagementManager(this, timer, DEFAULT_ENGAGEMENT_INTERVAL_MILLIS, event, intervalCalculator);
         engagementManager.start();
     }
 
@@ -365,7 +364,7 @@ public void trackPlay(
         // Start a new engagement manager for the video.
         @NonNull final Map<String, Object> hbEvent = eventsBuilder.buildEvent(url, urlRef, "vheartbeat", videoMetadata, extraData, uuid);
         // TODO: Can we remove some metadata fields from this request?
-        videoEngagementManager = new EngagementManager(timer, DEFAULT_ENGAGEMENT_INTERVAL_MILLIS, hbEvent);
+        videoEngagementManager = new EngagementManager(this, timer, DEFAULT_ENGAGEMENT_INTERVAL_MILLIS, hbEvent, intervalCalculator);
         videoEngagementManager.start();
     }
 
@@ -416,7 +415,7 @@ public void resetVideo() {
      *
      * @param event The event Map to enqueue.
      */
-    private void enqueueEvent(Map<String, Object> event) {
+    void enqueueEvent(Map<String, Object> event) {
         // Push it onto the queue
         eventQueue.add(event);
         new QueueManager().execute();
@@ -722,118 +721,4 @@ private void flushEvents() {
         new FlushQueue().execute();
     }
 
-    /**
-     * Engagement manager for article and video engagement.
-     * <p>
-     * Implemented to handle its own queuing of future executions to accomplish
-     * two things:
-     * <p>
-     * 1. Flushing any engaged time before canceling.
-     * 2. Progressive backoff for long engagements to save data.
-     */
-    private class EngagementManager {
-
-        public Map<String, Object> baseEvent;
-        private boolean started;
-        private final Timer parentTimer;
-        private TimerTask waitingTimerTask;
-        private long latestDelayMillis, totalTime;
-        private Calendar startTime;
-
-        private static final long MAX_TIME_BETWEEN_HEARTBEATS = 60 * 60;
-        private static final long OFFSET_MATCHING_BASE_INTERVAL = 35;
-        private static final double BACKOFF_PROPORTION = 0.3;
-
-
-        public EngagementManager(Timer parentTimer, long intervalMillis, Map<String, Object> baseEvent) {
-            this.baseEvent = baseEvent;
-            this.parentTimer = parentTimer;
-            latestDelayMillis = intervalMillis;
-            totalTime = 0;
-            startTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
-        }
-
-        public boolean isRunning() {
-            return started;
-        }
-
-        public void start() {
-            scheduleNextExecution(latestDelayMillis);
-            started = true;
-            startTime = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
-        }
-
-        public void stop() {
-            waitingTimerTask.cancel();
-            started = false;
-        }
-
-        public boolean isSameVideo(String url, String urlRef, ParselyVideoMetadata metadata) {
-            Map<String, Object> baseMetadata = (Map<String, Object>) baseEvent.get("metadata");
-            return (baseEvent.get("url").equals(url) &&
-                    baseEvent.get("urlref").equals(urlRef) &&
-                    baseMetadata.get("link").equals(metadata.link) &&
-                    (int) (baseMetadata.get("duration")) == metadata.durationSeconds);
-        }
-
-        private void scheduleNextExecution(long delay) {
-            TimerTask task = new TimerTask() {
-                public void run() {
-                    doEnqueue(scheduledExecutionTime());
-                    updateLatestInterval();
-                    scheduleNextExecution(latestDelayMillis);
-                }
-
-                public boolean cancel() {
-                    boolean output = super.cancel();
-                    // Only enqueue when we actually canceled something. If output is false then
-                    // this has already been canceled.
-                    if (output) {
-                        doEnqueue(scheduledExecutionTime());
-                    }
-                    return output;
-                }
-            };
-            latestDelayMillis = delay;
-            parentTimer.schedule(task, delay);
-            waitingTimerTask = task;
-        }
-
-        private void doEnqueue(long scheduledExecutionTime) {
-            // Create a copy of the base event to enqueue
-            Map<String, Object> event = new HashMap<>(baseEvent);
-            PLog(String.format("Enqueuing %s event.", event.get("action")));
-
-            // Update `ts` for the event since it's happening right now.
-            Calendar now = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
-            @SuppressWarnings("unchecked")
-            Map<String, Object> baseEventData = (Map<String, Object>) event.get("data");
-            assert baseEventData != null;
-            Map<String, Object> data = new HashMap<>((Map<String, Object>) baseEventData);
-            data.put("ts", now.getTimeInMillis());
-            event.put("data", data);
-
-            // Adjust inc by execution time in case we're late or early.
-            long executionDiff = (System.currentTimeMillis() - scheduledExecutionTime);
-            long inc = (latestDelayMillis + executionDiff);
-            totalTime += inc;
-            event.put("inc", inc / 1000);
-            event.put("tt", totalTime);
-
-            enqueueEvent(event);
-        }
-
-        private void updateLatestInterval() {
-            Calendar now = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
-            long totalTrackedTime = (now.getTime().getTime() - startTime.getTime().getTime()) / 1000;
-            double totalWithOffset = totalTrackedTime + OFFSET_MATCHING_BASE_INTERVAL;
-            double newInterval = totalWithOffset * BACKOFF_PROPORTION;
-            long clampedNewInterval = (long)Math.min(MAX_TIME_BETWEEN_HEARTBEATS, newInterval);
-            latestDelayMillis = clampedNewInterval * 1000;
-        }
-
-        public double getIntervalMillis() {
-            return latestDelayMillis;
-        }
-    }
 }

parsely/src/main/java/com/parsely/parselyandroid/UpdateEngagementIntervalCalculator.java

@@ -0,0 +1,22 @@
+package com.parsely.parselyandroid;
+
+import androidx.annotation.NonNull;
+
+import java.util.Calendar;
+import java.util.TimeZone;
+
+class UpdateEngagementIntervalCalculator {
+
+    private static final long MAX_TIME_BETWEEN_HEARTBEATS = 60 * 60;
+    private static final long OFFSET_MATCHING_BASE_INTERVAL = 35;
+    private static final double BACKOFF_PROPORTION = 0.3;
+
+    long updateLatestInterval(@NonNull final Calendar startTime) {
+        Calendar now = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
+        long totalTrackedTime = (now.getTime().getTime() - startTime.getTime().getTime()) / 1000;
+        double totalWithOffset = totalTrackedTime + OFFSET_MATCHING_BASE_INTERVAL;
+        double newInterval = totalWithOffset * BACKOFF_PROPORTION;
+        long clampedNewInterval = (long) Math.min(MAX_TIME_BETWEEN_HEARTBEATS, newInterval);
+        return clampedNewInterval * 1000;
+    }
+}