add exceptions to handle index out of bound error

Author: YingxuH

src/main/java/Duke.java

@@ -1,14 +1,9 @@
 //package java;
 
+import exceptions.*;
 import parser.Command;
 import parser.Parser;
 
-import exceptions.IllegalDateTimeFormatException;
-import exceptions.InvalidStorageFilePathException;
-import exceptions.NoCommandException;
-import exceptions.StorageOperationException;
-import exceptions.NoDescriptionException;
-
 import model.TaskList;
 
 import storage.Storage;
@@ -66,7 +61,10 @@ public String getResponse(String input) throws RuntimeException{
             assert commandResult.length() > 0: "The response message is empty";
 
             return commandResult;
-        } catch (NoDescriptionException | NoCommandException | IllegalDateTimeFormatException e) {
+        } catch (NoDescriptionException
+                | NoCommandException
+                | IllegalDateTimeFormatException
+                | IllegalPositionException e) {
             return e.getMessage();
         } catch (IOException e) {
             throw new RuntimeException(e);

src/main/java/exceptions/IllegalPositionException.java

@@ -0,0 +1,5 @@
+package exceptions;
+
+public class IllegalPositionException extends Exception {
+    public IllegalPositionException(String cause) { super(cause); }
+}

src/main/java/model/TaskList.java

@@ -1,5 +1,7 @@
 package model;
 
+import exceptions.IllegalPositionException;
+
 import java.time.LocalDate;
 
 import java.util.ArrayList;
@@ -65,9 +67,15 @@ public String add(Task task) {
      * @param position A position within the bound of the list.
      * @return response of the remove action.
      */
-    public String remove(int position) {
+    public String remove(int position) throws IllegalPositionException {
         assert this.internalList.size() > 0: "task list is empty, cannot delete";
 
+
+        if (position < 0 || position >= internalList.size()) {
+            throw new IllegalPositionException("Oops!!! The input position "
+                    + Integer.toString(position)
+                    + " is out of the boundary!\n");
+        }
         Task deletedTask = internalList.get(position);
         internalList.remove(position);
         return ECHO_DELETE_TASK
@@ -84,9 +92,14 @@ public String remove(int position) {
      * @param position A position within the bound of the list.
      * @return response of the mark action.
      */
-    public String markTaskAsDone(Integer position) {
+    public String markTaskAsDone(int position) throws IllegalPositionException {
         assert this.internalList.size() > 0: "task list is empty, cannot mark";
 
+        if (position < 0 || position >= internalList.size()) {
+            throw new IllegalPositionException("Oops!!! The input position "
+                    + Integer.toString(position)
+                    + " is out of the boundary!\n");
+        }
         Task finishedTask = this.internalList.get(position);
         finishedTask.markAsDone();
         return ECHO_COMPLETE_TASK

src/main/java/parser/Command.java

@@ -1,6 +1,7 @@
 package parser;
 
 import exceptions.IllegalDateTimeFormatException;
+import exceptions.IllegalPositionException;
 import exceptions.NoDescriptionException;
 import model.TaskList;
 
@@ -113,5 +114,5 @@ public String findKeyword(Pattern pattern, String input) {
         return matcher.group(POSITION_KEYWORD);
     }
 
-    public abstract String execute() throws NoDescriptionException;
+    public abstract String execute() throws NoDescriptionException, IllegalPositionException;
 }

src/main/java/parser/DeleteCommand.java

@@ -1,5 +1,7 @@
 package parser;
 
+import exceptions.IllegalPositionException;
+
 import static parser.Parser.DELETE_PATTERN;
 
 /**
@@ -21,7 +23,7 @@ public class DeleteCommand extends Command {
      * @return response from the TaskList class as a string.
      */
     @Override
-    public String execute() {
+    public String execute() throws IllegalPositionException {
         return this.taskList.remove(this.position);
     }
 }

src/main/java/parser/FinishCommand.java

@@ -1,5 +1,7 @@
 package parser;
 
+import exceptions.IllegalPositionException;
+
 import static parser.Parser.FINISH_PATTERN;
 
 /**
@@ -20,7 +22,7 @@ public class FinishCommand extends Command {
      * Mark a task at the inputted position as done.
      * @return response from the TaskList class as a string.
      */
-    public String execute() {
+    public String execute() throws IllegalPositionException {
         return this.taskList.markTaskAsDone(position);
     }
 }