Refactor predicates in Model & Improve the test structure

src/main/java/trackitnus/commons/core/Messages.java

@@ -13,10 +13,8 @@ public class Messages {
     public static final String MESSAGE_INVALID_TAB_VALUE = "Invalid tab values.";
     public static final String MESSAGE_CONTACTS_LISTED_OVERVIEW = "%1$d contacts listed!";
     public static final String MESSAGE_LESSON_DOES_NOT_EXIST = "There is no such lesson";
-    public static final String MESSAGE_TASKS_LISTED_OVERVIEW = "%1$d tasks listed!";
     public static final String MESSAGE_INVALID_LESSON_DISPLAYED_INDEX = "The lesson index provided is invalid";
 
-    public static final String MESSAGE_INVALID_MODULE_DISPLAYED_INDEX = "The module index provided is invalid";
     public static final String MESSAGE_MODULE_DOES_NOT_EXIST = "The module specified in the command doesn't exist.";
     public static final String MESSAGE_TASK_DOES_NOT_EXIST = "There is no such task";
 
@@ -25,4 +23,8 @@ public class Messages {
     public static final String MESSAGE_NOT_EDITED = "At least one field to edit must be provided.";
     public static final String MESSAGE_DUPLICATE_MODULE = "This module already exists";
     public static final String MESSAGE_DUPLICATE_TASK = "This task already exists";
+    public static final String MESSAGE_INVALID_INDEX = "Index is not a non-zero unsigned integer.";
+    public static final String DATE_MESSAGE_CONSTRAINTS = "Date should be in the format dd/MM/yyyy";
+    public static final String WEIGHTAGE_MESSAGE_CONSTRAINTS = "Weightage should be in the"
+        + " form of a floating point number";
 }

src/main/java/trackitnus/logic/commands/task/EditTaskCommand.java

@@ -113,6 +113,14 @@ public boolean equals(Object other) {
             && editTaskDescriptor.equals(e.editTaskDescriptor);
     }
 
+    @Override
+    public String toString() {
+        return "EditTaskCommand{" +
+            "index=" + index +
+            ", editTaskDescriptor=" + editTaskDescriptor +
+            '}';
+    }
+
     /**
      * Stores the details to edit the task with. Each non-empty field value will replace the
      * corresponding field value of the task.
@@ -183,7 +191,7 @@ public Optional<String> getRemark() {
         }
 
         public void setRemark(String remark) {
-            this.remark = remark;
+            this.remark = (remark == null ? "" : remark);
             this.isRemarkChanged = true;
         }
 
@@ -215,5 +223,15 @@ public boolean equals(Object other) {
                 && getDate().equals(e.getDate())
                 && getRemark().equals(e.getRemark());
         }
+
+        @Override
+        public String toString() {
+            return "EditTaskDescriptor{" +
+                "name=" + name +
+                ", date=" + date +
+                ", code=" + code +
+                ", remark='" + remark +
+                '}';
+        }
     }
 }

src/main/java/trackitnus/logic/parser/ParserUtil.java

@@ -4,12 +4,14 @@
 
 import java.time.LocalDate;
 import java.time.LocalTime;
+import java.time.format.DateTimeFormatter;
 import java.time.format.DateTimeParseException;
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Optional;
 import java.util.Set;
 
+import trackitnus.commons.core.Messages;
 import trackitnus.commons.core.index.Index;
 import trackitnus.commons.util.StringUtil;
 import trackitnus.logic.parser.exceptions.ParseException;
@@ -23,14 +25,13 @@
 import trackitnus.model.lesson.LessonDateTime;
 import trackitnus.model.lesson.Type;
 import trackitnus.model.tag.Tag;
-import trackitnus.model.task.Task;
 
 /**
  * Contains utility methods used for parsing strings in the various *Parser classes.
  */
 public class ParserUtil {
 
-    public static final String MESSAGE_INVALID_INDEX = "Index is not a non-zero unsigned integer.";
+    public static final DateTimeFormatter DATE_PATTERN = DateTimeFormatter.ofPattern("dd/MM/yyyy");
 
     /**
      * Parses {@code oneBasedIndex} into an {@code Index} and returns it. Leading and trailing whitespaces will be
@@ -41,7 +42,7 @@ public class ParserUtil {
     public static Index parseIndex(String oneBasedIndex) throws ParseException {
         String trimmedIndex = oneBasedIndex.trim();
         if (!StringUtil.isNonZeroUnsignedInteger(trimmedIndex)) {
-            throw new ParseException(MESSAGE_INVALID_INDEX);
+            throw new ParseException(Messages.MESSAGE_INVALID_INDEX);
         }
         return Index.fromOneBased(Integer.parseInt(trimmedIndex));
     }
@@ -198,9 +199,26 @@ public static LocalDate parseDate(String date) throws ParseException {
         requireNonNull(date);
         String trimmedDate = date.trim();
         try {
-            return LocalDate.parse(trimmedDate, Task.FORMATTER);
+            return LocalDate.parse(trimmedDate, DATE_PATTERN);
         } catch (DateTimeParseException e) {
-            throw new ParseException(Task.DATE_MESSAGE_CONSTRAINTS);
+            throw new ParseException(Messages.DATE_MESSAGE_CONSTRAINTS);
+        }
+    }
+
+    /**
+     * Parses a VALID {@code String date} into a {@code LocalDate}.
+     * Leading and trailing whitespaces will be trimmed.
+     * Crash the program if the date cannot be parsed (it's the caller responsibility to make sure the date passed in
+     * is valid!). The function is written so that the caller doesn't need to handle the possible exception since
+     * it's expected that no exception will be thrown.
+     */
+    public static LocalDate parseValidDate(String date) {
+        requireNonNull(date);
+        String trimmedDate = date.trim();
+        try {
+            return LocalDate.parse(trimmedDate, DATE_PATTERN);
+        } catch (DateTimeParseException e) {
+            throw new IllegalArgumentException("An invalid date has been passed into parseValidDate");
         }
     }
 
@@ -216,7 +234,7 @@ public static double parseWeightage(String weightage) throws ParseException {
         try {
             return Double.parseDouble(trimmedWeightage);
         } catch (NumberFormatException e) {
-            throw new ParseException(Task.WEIGHTAGE_MESSAGE_CONSTRAINTS);
+            throw new ParseException(Messages.WEIGHTAGE_MESSAGE_CONSTRAINTS);
         }
     }
 
@@ -242,17 +260,22 @@ public static String parseRemark(Optional<String> remark) {
      */
     public static Type parseType(String type) throws ParseException {
         requireNonNull(type);
-        String rawType = type.trim();
+        String rawType = type.trim().toLowerCase();
         switch (rawType) {
         case "lecture":
+        case "lec":
             return Type.LEC;
         case "tutorial":
+        case "tut":
             return Type.TUT;
         case "lab":
+        case "laboratory":
             return Type.LAB;
         case "recitation":
+        case "rec":
             return Type.REC;
         case "sectional":
+        case "sec":
             return Type.SEC;
         default:
             throw new ParseException(Lesson.TYPE_MESSAGE_CONSTRAINTS);
@@ -284,7 +307,7 @@ private static DayOfWeek parseLessonWeekday(String weekday) throws ParseExceptio
         case "sat":
             return DayOfWeek.Sat;
         default:
-            throw new ParseException(Lesson.DATE_MESSAGE_CONSTRAINTS);
+            throw new ParseException(Lesson.LESSON_TIME_MESSAGE_CONSTRAINTS);
         }
     }
 
@@ -311,7 +334,7 @@ public static LessonDateTime parseLessonDateTime(String date) throws ParseExcept
             if (e instanceof ParseException) {
                 throw e;
             } else {
-                throw new ParseException(Lesson.DATE_MESSAGE_CONSTRAINTS);
+                throw new ParseException(Lesson.LESSON_TIME_MESSAGE_CONSTRAINTS);
             }
         }
     }

src/main/java/trackitnus/logic/parser/lesson/AddLessonCommandParser.java

@@ -43,8 +43,7 @@ public AddLessonCommand parse(String args) throws ParseException {
             ArgumentTokenizer.tokenize(args,
                 PREFIX_CODE, PREFIX_TYPE, PREFIX_DATE);
 
-        if (!arePrefixesPresent(argMultimap, PREFIX_CODE, PREFIX_TYPE, PREFIX_DATE)
-            || !argMultimap.getPreamble().isEmpty()) {
+        if (!arePrefixesPresent(argMultimap, PREFIX_CODE, PREFIX_TYPE, PREFIX_DATE)) {
             throw new ParseException(String.format(Messages.MESSAGE_INVALID_COMMAND_FORMAT,
                 AddLessonCommand.MESSAGE_USAGE));
         }

src/main/java/trackitnus/model/ModelManager.java

@@ -20,12 +20,19 @@
 import trackitnus.model.commons.Code;
 import trackitnus.model.commons.Name;
 import trackitnus.model.contact.Contact;
+import trackitnus.model.contact.ContactHasTagPredicate;
 import trackitnus.model.lesson.DayOfWeek;
 import trackitnus.model.lesson.Lesson;
+import trackitnus.model.lesson.LessonHasCodePredicate;
+import trackitnus.model.lesson.LessonOnWeekdayPredicate;
 import trackitnus.model.lesson.Type;
 import trackitnus.model.module.Module;
 import trackitnus.model.tag.Tag;
 import trackitnus.model.task.Task;
+import trackitnus.model.task.TaskAfterDatePredicate;
+import trackitnus.model.task.TaskHasCodePredicate;
+import trackitnus.model.task.TaskIsOverduePredicate;
+import trackitnus.model.task.TaskOnDatePredicate;
 
 /**
  * Represents the in-memory model of the address book data.
@@ -302,14 +309,12 @@ public ObservableList<Lesson> getDayUpcomingLessons(LocalDate date) {
         sortLesson();
         updateFilteredLessonList(PREDICATE_SHOW_ALL_LESSONS);
         DayOfWeek weekday = DayOfWeek.getLessonWeekDay(date);
-        Predicate<Lesson> predicate = lesson -> (lesson.getWeekday().equals(weekday));
-        return getFilteredLessonList().filtered(predicate);
+        return getFilteredLessonList().filtered(new LessonOnWeekdayPredicate(weekday));
     }
 
     @Override
     public ObservableList<Lesson> getModuleLessons(Code code) {
-        Predicate<Lesson> predicate = lesson -> (lesson.getCode().equals(code));
-        updateFilteredLessonList(predicate);
+        updateFilteredLessonList(new LessonHasCodePredicate(code));
         return getFilteredLessonList();
     }
 
@@ -326,39 +331,33 @@ public Index getLessonIndex(Lesson lesson) throws CommandException {
     @Override
     public ObservableList<Contact> getModuleContacts(Code code) {
         Tag target = new Tag(code.toString());
-        Predicate<Contact> predicate = contact -> (contact.getTags().contains(target));
-        updateFilteredContactList(predicate);
+        updateFilteredContactList(new ContactHasTagPredicate(target));
         return getFilteredContactList();
     }
 
     @Override
     public ObservableList<Task> getModuleTasks(Code code) {
-        Predicate<Task> p = task -> task.belongsToModule(code);
-        updateFilteredTaskList(p);
+        updateFilteredTaskList(new TaskHasCodePredicate(code));
         return getFilteredTaskList();
     }
 
     @Override
     public ObservableList<Task> getOverdueTasks() {
         updateFilteredTaskList(Model.PREDICATE_SHOW_ALL_TASKS);
-        LocalDate today = LocalDate.now();
-        Predicate<Task> p = task -> task.getDate().isBefore(today);
-        return getFilteredTaskList().filtered(p);
+        return getFilteredTaskList().filtered(new TaskIsOverduePredicate());
     }
 
     @Override
     public ObservableList<Task> getFutureTasks() {
         updateFilteredTaskList(Model.PREDICATE_SHOW_ALL_TASKS);
         LocalDate oneWeekLater = LocalDate.now().plusWeeks(1);
-        Predicate<Task> p = task -> task.getDate().isAfter(oneWeekLater);
-        return getFilteredTaskList().filtered(p);
+        return getFilteredTaskList().filtered(new TaskAfterDatePredicate(oneWeekLater));
     }
 
     @Override
     public ObservableList<Task> getDayUpcomingTasks(LocalDate date) {
         updateFilteredTaskList(Model.PREDICATE_SHOW_ALL_TASKS);
-        Predicate<Task> p = task -> task.getDate().equals(date);
-        return getFilteredTaskList().filtered(p);
+        return getFilteredTaskList().filtered(new TaskOnDatePredicate(date));
     }
 
     @Override

src/main/java/trackitnus/model/contact/ContactHasTagPredicate.java

@@ -0,0 +1,26 @@
+package trackitnus.model.contact;
+
+import java.util.function.Predicate;
+
+import trackitnus.model.tag.Tag;
+
+public class ContactHasTagPredicate implements Predicate<Contact> {
+
+    private final Tag tag;
+
+    public ContactHasTagPredicate(Tag tag) {
+        this.tag = tag;
+    }
+
+    @Override
+    public boolean test(Contact contact) {
+        return contact.getTags().contains(tag);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+            || (other instanceof ContactHasTagPredicate // instanceof handles nulls
+            && tag.equals(((ContactHasTagPredicate) other).tag)); // state check
+    }
+}

src/main/java/trackitnus/model/lesson/Lesson.java

@@ -18,8 +18,8 @@ public class Lesson {
     public static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("d/MM/yyyy");
     public static final String TIME_MESSAGE_CONSTRAINTS =
         "Starting time should be earlier than finishing time";
-    public static final String DATE_MESSAGE_CONSTRAINTS =
-        "Date should be in the format \"ddd H:mm-H:mm\" (in 24-hour format), e.g. Mon 8:00-13:00";
+    public static final String LESSON_TIME_MESSAGE_CONSTRAINTS =
+        "Lesson's time should be in the format \"ddd H:mm-H:mm\" (in 24-hour format), e.g. Mon 8:00-13:00";
     public static final String WEIGHTAGE_MESSAGE_CONSTRAINTS =
         "Weightage should be in the form of a floating point number";
     public static final String TYPE_MESSAGE_CONSTRAINTS =

src/main/java/trackitnus/model/lesson/LessonHasCodePredicate.java

@@ -0,0 +1,26 @@
+package trackitnus.model.lesson;
+
+import java.util.function.Predicate;
+
+import trackitnus.model.commons.Code;
+
+public class LessonHasCodePredicate implements Predicate<Lesson> {
+
+    private final Code code;
+
+    public LessonHasCodePredicate(Code code) {
+        this.code = code;
+    }
+
+    @Override
+    public boolean test(Lesson lesson) {
+        return lesson.getCode().equals(code);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+            || (other instanceof LessonHasCodePredicate // instanceof handles nulls
+            && code.equals(((LessonHasCodePredicate) other).code)); // state check
+    }
+}

src/main/java/trackitnus/model/lesson/LessonOnWeekdayPredicate.java

@@ -0,0 +1,24 @@
+package trackitnus.model.lesson;
+
+import java.util.function.Predicate;
+
+public class LessonOnWeekdayPredicate implements Predicate<Lesson> {
+
+    private final DayOfWeek weekday;
+
+    public LessonOnWeekdayPredicate(DayOfWeek weekday) {
+        this.weekday = weekday;
+    }
+
+    @Override
+    public boolean test(Lesson lesson) {
+        return lesson.getWeekday().equals(weekday);
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+            || (other instanceof LessonOnWeekdayPredicate // instanceof handles nulls
+            && weekday.equals(((LessonOnWeekdayPredicate) other).weekday)); // state check
+    }
+}

src/main/java/trackitnus/model/lesson/exceptions/DuplicateLessonException.java

@@ -6,6 +6,6 @@
  */
 public class DuplicateLessonException extends RuntimeException {
     public DuplicateLessonException() {
-        super("Operation would result in duplicate contacts");
+        super("Operation would result in duplicate lesson");
     }
 }

src/main/java/trackitnus/model/task/Task.java

@@ -1,7 +1,6 @@
 package trackitnus.model.task;
 
 import java.time.LocalDate;
-import java.time.format.DateTimeFormatter;
 import java.util.Objects;
 import java.util.Optional;
 
@@ -16,10 +15,6 @@
  */
 public class Task {
     public static final String TYPE = "T";
-    public static final String DATE_MESSAGE_CONSTRAINTS = "Date should be in the format dd/MM/yyyy or dd/MM/yyyy hh:mm";
-    public static final String WEIGHTAGE_MESSAGE_CONSTRAINTS = "Weightage should be in the"
-        + " form of a floating point number";
-    public static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("dd/MM/yyyy");
 
     private final Name name;
     private final LocalDate date;