Improve code readability

src/main/java/seedu/address/logic/commands/EndTestCommand.java

@@ -21,15 +21,20 @@ public class EndTestCommand extends Command {
 
     public EndTestCommand(KeyboardFlashCardsParser keyboardFlashCardsParser) {
         requireNonNull(keyboardFlashCardsParser);
+
         this.keyboardFlashCardsParser = keyboardFlashCardsParser;
     }
 
     @Override
     public CommandResult execute(Model model) {
+        requireNonNull(model);
+
         model.updatePerformance(model);
         logger.log(Level.INFO, "Updating performance");
+
         keyboardFlashCardsParser.endTestMode();
         logger.log(Level.INFO, "Enabling KeyboardFlashCardsParser to accept normal commands");
+
         CommandResult result = new CommandResult("Test ended");
         result.setTestMode(false, true);
         return result;

src/main/java/seedu/address/logic/commands/NextQuestionCommand.java

@@ -28,12 +28,16 @@ abstract class NextQuestionCommand extends Command {
     @Override
     public CommandResult execute(Model model) {
         requireNonNull(model);
+
         if (!model.hasTestFlashCard()) {
             logger.log(Level.INFO, "No more flashcards left to test!");
+
             keyboardFlashCardsParser.endTestMode();
             logger.log(Level.INFO, "Enabling KeyboardFlashCardsParser to accept normal commands");
+
             model.updatePerformance(model);
             logger.log(Level.INFO, "Updating performance");
+
             CommandResult result = new CommandResult(MESSAGE_SUCCESS_END_OF_TEST);
             result.setTestMode(false, true);
             return result;
@@ -42,6 +46,7 @@ public CommandResult execute(Model model) {
         model.setTestFlashCard();
         keyboardFlashCardsParser.setAwaitingAnswer(true);
         logger.log(Level.INFO, "Getting the next flashcard");
+
         return new CommandResult(
                 messageSuccess,
                 model.getTestFlashCardPanel());

src/main/java/seedu/address/logic/commands/RateQuestionCommand.java

@@ -25,14 +25,17 @@ public class RateQuestionCommand extends NextQuestionCommand {
 
     public RateQuestionCommand(KeyboardFlashCardsParser keyboardFlashCardsParser, Rating rating) {
         super(keyboardFlashCardsParser, MESSAGE_SUCCESS);
+
         requireNonNull(rating);
+
         this.keyboardFlashCardsParser = keyboardFlashCardsParser;
         this.rating = rating;
     }
 
     @Override
     public CommandResult execute(Model model) {
         requireNonNull(model);
+
         updateModelStatistics(model);
         updateFlashCardRating(model);
         return super.execute(model);
@@ -50,8 +53,10 @@ public boolean equals(Object other) {
     /** Updates statistics in the model. */
     private void updateModelStatistics(Model model) {
         assert model != null;
+
         String rating = this.rating.toString();
         assert rating.equals("good") || rating.equals("hard") || rating.equals("easy");
+
         switch (rating) {
         case "good":
             model.editStats(0);
@@ -70,14 +75,17 @@ private void updateModelStatistics(Model model) {
     /** Updates the rating of a flashcard. */
     private void updateFlashCardRating(Model model) {
         assert model != null;
+
         FlashCard flashCardToUpdate = model.getCurrentTestFlashCard();
         assert flashCardToUpdate != null;
+
         model.setFlashCard(flashCardToUpdate, createUpdatedFlashCard(flashCardToUpdate));
     }
 
     /** Creates a new immutable flashcard with the updated rating. */
     private FlashCard createUpdatedFlashCard(FlashCard flashCardToUpdate) {
         assert flashCardToUpdate != null;
+
         return new FlashCard(flashCardToUpdate.getQuestion(),
                 flashCardToUpdate.getAnswer(),
                 rating, flashCardToUpdate.getCategories());

src/main/java/seedu/address/logic/commands/ShowAnswerCommand.java

@@ -21,12 +21,14 @@ public class ShowAnswerCommand extends Command {
 
     public ShowAnswerCommand(KeyboardFlashCardsParser keyboardFlashCardsParser) {
         requireNonNull(keyboardFlashCardsParser);
+
         this.keyboardFlashCardsParser = keyboardFlashCardsParser;
     }
 
     @Override
     public CommandResult execute(Model model) {
         requireNonNull(model);
+
         model.showAnswer();
         keyboardFlashCardsParser.setAwaitingAnswer(false);
         return new CommandResult(MESSAGE_SHOW_ANSWER_SUCCESS);

src/main/java/seedu/address/logic/commands/StartCommand.java

@@ -48,12 +48,15 @@ public StartCommand(KeyboardFlashCardsParser keyboardFlashCardsParser, String ta
     @Override
     public CommandResult execute(Model model) {
         requireNonNull(model);
+
         List<FlashCard> testList = searchTag(model);
         model.initializeTestModel(testList);
+
         if (!model.hasTestFlashCard()) {
             logger.log(Level.WARNING, String.format("No flashcards found with the following tag(s):\n%s", tagName));
             return new CommandResult(MESSAGE_NO_FLASHCARDS);
         }
+
         keyboardFlashCardsParser.startTestMode();
         model.setTestFlashCard();
         keyboardFlashCardsParser.setAwaitingAnswer(true);
@@ -63,6 +66,7 @@ public CommandResult execute(Model model) {
                 MESSAGE_START_TEST_SUCCESS,
                 model.getTestFlashCardPanel());
         result.setTestMode(true, false);
+
         return result;
 
     }
@@ -78,9 +82,11 @@ public boolean equals(Object other) {
     /** Searches the list of flashcard to fetch the relevant tags. */
     private List<FlashCard> searchTag(Model model) {
         assert model != null;
+
         if (tagName.isEmpty()) {
             return new LinkedList<>(model.getFlashCardList());
         }
+
         CategoryContainsAnyKeywordsPredicate predicate = getSearchTermPredicate();
         logger.log(Level.INFO, "Getting a list of flashcards to test");
         return model.getFilteredFlashCardListNoCommit(predicate);

src/main/java/seedu/address/logic/parser/RateQuestionCommandParser.java

@@ -36,6 +36,7 @@ public RateQuestionCommand parse(String args) throws ParseException {
                 && !rating.equals(Rating.HARD)) {
             throw new ParseException(String.format(MESSAGE_INVALID_COMMAND_FORMAT, RateQuestionCommand.MESSAGE_USAGE));
         }
+
         return new RateQuestionCommand(keyboardFlashCardsParser, new Rating(rating));
     }
 }

src/main/java/seedu/address/logic/parser/StartCommandParser.java

@@ -28,6 +28,7 @@ public StartCommand parse(String args) throws ParseException {
         if (!args.matches(alphaNumericWithSpacesRegex) && !args.isEmpty()) {
             throw new ParseException(BAD_ARGUMENTS);
         }
+
         String trimmedArgs = args.trim();
         return new StartCommand(keyboardFlashCardsParser, trimmedArgs);
     }

src/main/java/seedu/address/model/FlashCardTestModel.java

@@ -44,6 +44,7 @@ private void setTestFlashCardPanel() {
 
     public TestFlashCardPanel getTestFlashCardPanel() {
         requireNonNull(currentFlashCard);
+
         setTestFlashCardPanel();
         return testFlashCardPanel;
     }