chore: clarify min polling interval as 15 mins (#319)

Author: jaeopt

.gitignore

@@ -6,3 +6,5 @@
 /build
 /captures
 values.gradle
+jacoco.exec
+

android-sdk/src/main/java/com/optimizely/ab/android/sdk/OptimizelyManager.java

@@ -54,6 +54,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.List;
 import java.util.Set;
 
 
@@ -677,6 +678,7 @@ public static class Builder {
          * Sets the interval which {@link DatafileService} through the {@link DatafileHandler} will attempt to update the
          * cached datafile.  If you set this to -1, you disable background updates.  If you don't set
          * a download interval (or set to less than 0), then no background updates will be scheduled or occur.
+         * The minimum interval is 900 secs (15 minutes) (enforced by the Android JobScheduler API. See {@link android.app.job.JobInfo})
          *
          * @param interval the interval in seconds
          * @return this {@link Builder} instance
@@ -789,10 +791,10 @@ public OptimizelyManager build(Context context) {
             }
 
             if (datafileDownloadInterval > 0) {
-                // AlarmManager doesn't allow intervals less than 60 seconds
-                if (datafileDownloadInterval < 60) {
-                    datafileDownloadInterval = 60;
-                    logger.warn("Minimum datafile polling interval is 60 seconds. Defaulting to 60 seconds.");
+                // JobScheduler API doesn't allow intervals less than 15 minutes
+                if (datafileDownloadInterval < 900) {
+                    datafileDownloadInterval = 900;
+                    logger.warn("Minimum datafile polling interval is 15 minutes. Defaulting to 15 minutes.");
                 }
             }
 

android-sdk/src/test/java/com/optimizely/ab/android/sdk/OptimizelyManagerBuilderTest.java

@@ -61,7 +61,7 @@ public void testBuildWithInvalidPollingInterval() {
                 .withDatafileDownloadInterval(5L)
                 .build(appContext);
 
-        assertEquals(60L, manager.getDatafileDownloadInterval().longValue());
+        assertEquals(900L, manager.getDatafileDownloadInterval().longValue());
     }
 
     /**
@@ -73,10 +73,10 @@ public void testBuildWithValidPollingInterval() {
         Context appContext = mock(Context.class);
         when(appContext.getApplicationContext()).thenReturn(appContext);
         OptimizelyManager manager = OptimizelyManager.builder("1")
-                .withDatafileDownloadInterval(61L)
+                .withDatafileDownloadInterval(901L)
                 .build(appContext);
 
-        assertEquals(61L, manager.getDatafileDownloadInterval().longValue());
+        assertEquals(901L, manager.getDatafileDownloadInterval().longValue());
     }
 
     @Test
@@ -85,11 +85,11 @@ public void testBuildWithEventHandler() {
         when(appContext.getApplicationContext()).thenReturn(appContext);
         EventHandler eventHandler = mock(EventHandler.class);
         OptimizelyManager manager = OptimizelyManager.builder(testProjectId)
-                .withDatafileDownloadInterval(61L)
+                .withDatafileDownloadInterval(901L)
                 .withEventHandler(eventHandler)
                 .build(appContext);
 
-        assertEquals(61L, manager.getDatafileDownloadInterval().longValue());
+        assertEquals(901L, manager.getDatafileDownloadInterval().longValue());
         assertEquals(manager.getEventHandler(appContext), eventHandler);
 
 

test-app/src/main/java/com/optimizely/ab/android/test_app/MyApplication.java

@@ -27,6 +27,7 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.UUID;
+import java.util.concurrent.TimeUnit;
 
 public class MyApplication extends Application {
 
@@ -74,7 +75,7 @@ public void onCreate() {
 
          OptimizelyManager.Builder builder = OptimizelyManager.builder();
          optimizelyManager =  builder.withEventDispatchInterval(60L * 1000L)
-            .withDatafileDownloadInterval(0)
+            .withDatafileDownloadInterval(TimeUnit.MINUTES.toSeconds(15))
             .withSDKKey("FCnSegiEkRry9rhVMroit4")
             .build(getApplicationContext());
     }