Add validation to disallow start time after end time

src/main/java/command/AddCommand.java

@@ -3,8 +3,9 @@
 import exception.DuplicateTaskException;
 import exception.ErrorAccessingFileException;
 import exception.InvalidCommandFormatException;
-import exception.InvalidDateTimeException;
+import exception.InvalidDateTimeFormatException;
 import exception.InvalidTaskTypeException;
+import exception.InvalidTimePeriodException;
 import exception.MissingCommandDescriptionException;
 import message.Message;
 import tasklist.Task;
@@ -46,27 +47,30 @@ public static AddCommand createCommand(String description, CommandTypeEnum comma
      * @return Message representing the command is executed.
      * @throws InvalidTaskTypeException If the task type is not valid.
      * @throws ErrorAccessingFileException If there is an error accessing the storage file.
-     * @throws InvalidDateTimeException If a task meant to contain time information has an invalid datetime format.
+     * @throws InvalidDateTimeFormatException If a task meant to contain datetime has an invalid datetime format.
      * @throws DuplicateTaskException If there is an attempt to add a duplicate task.
      * @throws InvalidCommandFormatException If the task has an incorrect format.
+     * @throws InvalidTimePeriodException If the start time is after the end time.
      */
     public Message execute(TaskList list) throws
             InvalidTaskTypeException,
             ErrorAccessingFileException,
-            InvalidDateTimeException,
+            InvalidDateTimeFormatException,
             DuplicateTaskException,
-            InvalidCommandFormatException {
+            InvalidCommandFormatException,
+            InvalidTimePeriodException {
         Task task = addTask(list);
         Message message = getOutputMessage(list, task);
         return message;
     }
 
     private Task addTask(TaskList list) throws
             InvalidTaskTypeException,
-            InvalidDateTimeException,
+            InvalidDateTimeFormatException,
             DuplicateTaskException,
             ErrorAccessingFileException,
-            InvalidCommandFormatException {
+            InvalidCommandFormatException,
+            InvalidTimePeriodException {
         Task task = Task.createTask(this.description, this.commandType);
 
         list.validateTaskNotDuplicate(task);

src/main/java/exception/InvalidDateTimeException.java → src/main/java/exception/InvalidDateTimeFormatException.java

@@ -3,13 +3,13 @@
 /**
  * Encapsulates an exception when an input has an invalid datetime format.
  */
-public class InvalidDateTimeException extends DukeException {
+public class InvalidDateTimeFormatException extends DukeException {
     /**
      * Instantiates an exception when an input has an invalid datetime format.
      *
      * @param format Required datetime format.
      */
-    public InvalidDateTimeException(String dateOrTime, String format) {
+    public InvalidDateTimeFormatException(String dateOrTime, String format) {
         super(String.format("%s should be in the form of <%s>", dateOrTime, format));
     }
 }

src/main/java/exception/InvalidTimePeriodException.java

@@ -0,0 +1,13 @@
+package exception;
+
+/**
+ * Encapsulates an exception when the start time is after the end time in a time period.
+ */
+public class InvalidTimePeriodException extends DukeException {
+    /**
+     * Instantiates an exception when the start time is after the end time in a time period.
+     */
+    public InvalidTimePeriodException() {
+        super("Start time cannot be after end time. The first time must be the start time.");
+    }
+}

src/main/java/parser/DateTimeParser.java

@@ -5,7 +5,7 @@
 import java.time.format.DateTimeFormatter;
 import java.time.format.DateTimeParseException;
 
-import exception.InvalidDateTimeException;
+import exception.InvalidDateTimeFormatException;
 
 /**
  * Encapsulates a parser for date time.
@@ -17,16 +17,16 @@ public class DateTimeParser {
      * @param dateString Date string.
      * @param dateFormat Format of date string.
      * @return `LocalDate`.
-     * @throws InvalidDateTimeException If there is an error parsing a string to a date.
+     * @throws InvalidDateTimeFormatException If there is an error parsing a string to a date.
      */
     public static LocalDate changeDateStringToDate(String dateString, String dateFormat)
-            throws InvalidDateTimeException {
+            throws InvalidDateTimeFormatException {
         DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern(dateFormat);
 
         try {
             return LocalDate.parse(dateString, dateFormatter);
         } catch (DateTimeParseException e) {
-            throw new InvalidDateTimeException("Date", dateFormat);
+            throw new InvalidDateTimeFormatException("Date", dateFormat);
         }
     }
 
@@ -36,16 +36,16 @@ public static LocalDate changeDateStringToDate(String dateString, String dateFor
      * @param timeString Time string.
      * @param timeFormat Format of time string.
      * @return `LocalTime`.
-     * @throws InvalidDateTimeException If there is an error parsing a string to a time.
+     * @throws InvalidDateTimeFormatException If there is an error parsing a string to a time.
      */
     public static LocalTime changeTimeStringToTime(String timeString, String timeFormat)
-            throws InvalidDateTimeException {
+            throws InvalidDateTimeFormatException {
         DateTimeFormatter timeFormatter = DateTimeFormatter.ofPattern(timeFormat);
 
         try {
             return LocalTime.parse(timeString, timeFormatter);
         } catch (DateTimeParseException e) {
-            throw new InvalidDateTimeException("Time", timeFormat);
+            throw new InvalidDateTimeFormatException("Time", timeFormat);
         }
     }
 

src/main/java/tasklist/DeadlineTask.java

@@ -4,7 +4,7 @@
 import java.time.LocalTime;
 
 import exception.InvalidCommandFormatException;
-import exception.InvalidDateTimeException;
+import exception.InvalidDateTimeFormatException;
 import exception.InvalidFormatInStorageException;
 import exception.InvalidNumOfStringPartsException;
 import parser.CommandParser;
@@ -34,11 +34,11 @@ private DeadlineTask(String description, boolean isDone, LocalDate date, LocalTi
      *
      * @param description Description including action and deadline information.
      * @return Deadline task.
-     * @throws InvalidDateTimeException If the description has an invalid datetime format.
+     * @throws InvalidDateTimeFormatException If the description has an invalid datetime format.
      * @throws InvalidCommandFormatException If the description has an invalid format.
      */
     public static DeadlineTask createTask(String description)
-            throws InvalidDateTimeException, InvalidCommandFormatException {
+            throws InvalidDateTimeFormatException, InvalidCommandFormatException {
         try {
             String[] actionAndDateTimeDescriptions = CommandParser.splitStringBySplitter(
                     description, SPLITTER_ACTION_TIME);
@@ -123,7 +123,7 @@ public static DeadlineTask createTaskFromStoredString(String description) throws
             LocalTime time = DateTimeParser.changeTimeStringToTime(dateTimeDescriptions[1], timeFormat);
 
             return new DeadlineTask(actionDescription, isDone, date, time);
-        } catch (InvalidDateTimeException | InvalidNumOfStringPartsException e) {
+        } catch (InvalidDateTimeFormatException | InvalidNumOfStringPartsException e) {
             String expectedFormat = String.format("[ ] <description> %s %s %s",
                     SPLITTER_ACTION_TIME, dateFormat, timeFormat);
             throw new InvalidFormatInStorageException(description, expectedFormat);

src/main/java/tasklist/EventTask.java

@@ -4,9 +4,10 @@
 import java.time.LocalTime;
 
 import exception.InvalidCommandFormatException;
-import exception.InvalidDateTimeException;
+import exception.InvalidDateTimeFormatException;
 import exception.InvalidFormatInStorageException;
 import exception.InvalidNumOfStringPartsException;
+import exception.InvalidTimePeriodException;
 import parser.CommandParser;
 import parser.DateTimeParser;
 import type.CommandTypeEnum;
@@ -36,11 +37,14 @@ private EventTask(String description, boolean isDone, LocalDate date, LocalTime
      *
      * @param description Description including action, date and time information.
      * @return Event task.
-     * @throws InvalidDateTimeException If the description has an invalid datetime format.
+     * @throws InvalidDateTimeFormatException If the description has an invalid datetime format.
      * @throws InvalidCommandFormatException If the description has an invalid format.
+     * @throws InvalidTimePeriodException If the start time is after the end time.
      */
-    public static EventTask createTask (String description)
-            throws InvalidDateTimeException, InvalidCommandFormatException {
+    public static EventTask createTask (String description) throws
+            InvalidDateTimeFormatException,
+            InvalidCommandFormatException,
+            InvalidTimePeriodException {
         try {
             String[] actionAndTimeDescriptions = CommandParser.splitStringBySplitter(
                     description,
@@ -59,6 +63,7 @@ public static EventTask createTask (String description)
                     dateTimeDescriptions[1], TimeFormatTypeEnum.INPUT.toString());
             LocalTime endTime = DateTimeParser.changeTimeStringToTime(
                     dateTimeDescriptions[2], TimeFormatTypeEnum.INPUT.toString());
+            validateStartTimeBeforeOrAtEndTime(startTime, endTime);
 
             return new EventTask(actionDescription, false, date, startTime, endTime);
         } catch (InvalidNumOfStringPartsException e) {
@@ -131,7 +136,7 @@ public static EventTask createTaskFromStoredString(String description) throws In
             LocalTime endTime = DateTimeParser.changeTimeStringToTime(dateTimeDescriptions[2], timeFormat);
 
             return new EventTask(actionDescription, isDone, date, startTime, endTime);
-        } catch (InvalidNumOfStringPartsException | InvalidDateTimeException e) {
+        } catch (InvalidNumOfStringPartsException | InvalidDateTimeFormatException e) {
             String expectedFormat = String.format("[ ] <description> %s %s %s",
                     SPLITTER_ACTION_TIME, dateFormat, timeFormat);
             throw new InvalidFormatInStorageException(description, expectedFormat);
@@ -162,4 +167,11 @@ protected boolean isDuplicateOf(Task task) {
 
         return this.endTime.equals(eventTask.endTime);
     }
+
+    private static void validateStartTimeBeforeOrAtEndTime(LocalTime startTime, LocalTime endTime)
+            throws InvalidTimePeriodException {
+        if (startTime.compareTo(endTime) > 0) {
+            throw new InvalidTimePeriodException();
+        }
+    }
 }

src/main/java/tasklist/Task.java

@@ -3,9 +3,10 @@
 import java.util.Arrays;
 
 import exception.InvalidCommandFormatException;
-import exception.InvalidDateTimeException;
+import exception.InvalidDateTimeFormatException;
 import exception.InvalidFormatInStorageException;
 import exception.InvalidTaskTypeException;
+import exception.InvalidTimePeriodException;
 import type.CommandTypeEnum;
 import type.TaskIconTypeEnum;
 
@@ -38,10 +39,14 @@ public Task(String description, boolean isDone) {
      * @return `Task`.
      * @throws InvalidTaskTypeException If the type of task is not recognised.
      * @throws InvalidCommandFormatException If the command is incorrectly formatted.
-     * @throws InvalidDateTimeException If there is an invalid date time.
+     * @throws InvalidDateTimeFormatException If there is an invalid date time.
+     * @throws InvalidTimePeriodException If the start time is after the end time.
      */
-    public static Task createTask(String description, CommandTypeEnum commandType)
-            throws InvalidTaskTypeException, InvalidCommandFormatException, InvalidDateTimeException {
+    public static Task createTask(String description, CommandTypeEnum commandType) throws
+            InvalidTaskTypeException,
+            InvalidCommandFormatException,
+            InvalidDateTimeFormatException,
+            InvalidTimePeriodException {
         switch (commandType) {
         case TODO:
             return TodoTask.createTask(description);