Fix#3146 : Create a generic utility for filtering enums

app/src/main/java/org/oppia/android/app/survey/surveyitemviewmodel/UserTypeItemsViewModel.kt

@@ -13,6 +13,7 @@ import org.oppia.android.app.survey.SelectedAnswerHandler
 import org.oppia.android.app.translation.AppLanguageResourceHandler
 import org.oppia.android.app.viewmodel.ObservableArrayList
 import javax.inject.Inject
+import org.oppia.android.util.enumfilter.filterByEnumCondition
 
 /** [SurveyAnswerItemViewModel] for providing the type of user question options. */
 class UserTypeItemsViewModel @Inject constructor(
@@ -96,9 +97,14 @@ class UserTypeItemsViewModel @Inject constructor(
   }
 
   private fun getUserTypeOptions(): ObservableArrayList<MultipleChoiceOptionContentViewModel> {
-    val observableList = ObservableArrayList<MultipleChoiceOptionContentViewModel>()
-    observableList += UserTypeAnswer.values()
-      .filter { it.isValid() }
+    val observableList=ObservableArrayList<MultipleChoiceOptionContentViewModel>()
+    val filteredUserTypes=filterByEnumCondition(
+      UserTypeAnswer.values().toList(),
+      {it},
+      {it.isValid()}
+    )
+    observableList+=filteredUserTypes
+
       .mapIndexed { index, userTypeOption ->
         when (userTypeOption) {
           UserTypeAnswer.LEARNER ->

app/src/main/java/org/oppia/android/app/topic/lessons/TopicLessonsFragmentPresenter.kt

@@ -31,6 +31,7 @@ import org.oppia.android.util.accessibility.AccessibilityService
 import org.oppia.android.util.data.AsyncResult
 import org.oppia.android.util.data.DataProviders.Companion.toLiveData
 import javax.inject.Inject
+import org.oppia.android.util.enumfilter.filterByEnumCondition
 
 /** The presenter for [TopicLessonsFragment]. */
 @FragmentScope
@@ -161,18 +162,20 @@ class TopicLessonsFragmentPresenter @Inject constructor(
 
     val chapterSummaries = storySummaryViewModel
       .storySummary.chapterList
-    val completedChapterCount =
-      chapterSummaries.map(ChapterSummary::getChapterPlayState)
-        .filter {
-          it == ChapterPlayState.COMPLETED
-        }
-        .size
-    val inProgressChapterCount =
-      chapterSummaries.map(ChapterSummary::getChapterPlayState)
-        .filter {
-          it == ChapterPlayState.IN_PROGRESS_SAVED
-        }
-        .size
+    val completedChapterCount=filterByEnumCondition(
+      chapterSummaries.map(ChapterSummary::getChapterPlayState),
+      {it},
+      {it==ChapterPlayState.COMPLETED}
+    ).size
+
+    val inProgressChapterCount=
+      filterByEnumCondition(
+        chapterSummaries.map(ChapterSummary::getChapterPlayState),
+        {it},
+        {it==ChapterPlayState.IN_PROGRESS_SAVED}
+      ).size
+
+
 
     val storyPercentage: Int =
       (completedChapterCount * 100) / storySummaryViewModel.storySummary.chapterCount

domain/src/main/java/org/oppia/android/domain/oppialogger/analytics/PerformanceMetricsController.kt

@@ -16,6 +16,7 @@ import org.oppia.android.util.networking.NetworkConnectionUtil
 import java.lang.IllegalStateException
 import javax.inject.Inject
 import javax.inject.Singleton
+import org.oppia.android.util.enumfilter.filterByEnumCondition
 
 /**
  * Controller for handling performance metrics event logging.
@@ -128,10 +129,12 @@ class PerformanceMetricsController @Inject constructor(
    * priority is returned.
    */
   private fun getLeastRecentMetricLogIndex(oppiaMetricLogs: OppiaMetricLogs): Int? =
-    oppiaMetricLogs.oppiaMetricLogList.withIndex()
-      .filter { it.value.priority == Priority.LOW_PRIORITY }
-      .minByOrNull { it.value.timestampMillis }?.index
-      ?: getLeastRecentMediumPriorityEventIndex(oppiaMetricLogs)
+    filterByEnumCondition(
+      oppiaMetricLogs.oppiaMetricLogList.withIndex().toList(),
+      {it.value.priority},
+      {it==Priority.LOW_PRIORITY}
+    ).minByOrNull{it.value.timestampMillis}?.index
+      ?:getLeastRecentMediumPriorityEventIndex(oppiaMetricLogs)
 
   /**
    * Returns the index of the least recent event from the existing store on the basis of recency and
@@ -142,10 +145,13 @@ class PerformanceMetricsController @Inject constructor(
    * priority is returned.
    */
   private fun getLeastRecentMediumPriorityEventIndex(oppiaMetricLogs: OppiaMetricLogs): Int? =
-    oppiaMetricLogs.oppiaMetricLogList.withIndex()
-      .filter { it.value.priority == Priority.MEDIUM_PRIORITY }
-      .minByOrNull { it.value.timestampMillis }?.index
-      ?: getLeastRecentGeneralEventIndex(oppiaMetricLogs)
+    filterByEnumCondition(
+      oppiaMetricLogs.oppiaMetricLogList.withIndex().toList(),
+      {it.value.priority},
+      {it==Priority.MEDIUM_PRIORITY}
+    ).minByOrNull{it.value.timestampMillis}?.index
+      ?:getLeastRecentGeneralEventIndex(oppiaMetricLogs)
+
 
   /** Returns the index of the least recent event regardless of their priority. */
   private fun getLeastRecentGeneralEventIndex(oppiaMetricLogs: OppiaMetricLogs): Int? =

utility/src/main/java/org/oppia/android/util/enumfilter/genericutilityforfilteringenums.kt

@@ -0,0 +1,10 @@
+package org.oppia.android.util.enumfilter
+// This function is used to filter the list of items based on the enum condition.
+// This function takes the collection of items, enumExtractor function which extracts the enum from the item and condition function which checks the condition on the enum.
+inline fun<E:Enum<E>,T>filterByEnumCondition(
+collection:Collection<T>,
+enumExtractor:(T)->E,
+condition:(E)->Boolean
+):List<T>{
+  return collection.filter{condition(enumExtractor(it))}
+}