Added task loading and saving functionality (Level-7)

Author: weixue123

data/duke.txt

@@ -0,0 +1,3 @@
+T | 1 | CS2107 Revision | 
+D | 1 | CS2103 Post-Lecture Quiz | 5 Feb 2021 2:00 AM
+E | 0 | BT4013 Nano-Quiz 4 | 8 Feb 2021 10:00 AM to 10:30 AM

src/main/java/Duke.java

@@ -7,9 +7,11 @@ public static void main(String[] args) {
         System.out.println("Hello! I'm Duke");
         System.out.println("What can I do for you?");
 
-        boolean appIsRunning = true;
         Scanner sc = new Scanner(System.in);
-        TaskList tasks = new TaskList();
+        Loader loader = new Loader();
+        TaskCollection tasks = loader.loadTasks();
+
+        boolean appIsRunning = true;
 
         while (appIsRunning) {
             InputHandler handler = new InputHandler(sc.nextLine());
@@ -27,6 +29,7 @@ public static void main(String[] args) {
                 case "bye":
                     System.out.println("Bye. Hope to see you again soon!");
                     appIsRunning = false;
+                    loader.saveTasks(tasks);
                     break;
 
                 case "list":

src/main/java/Loader.java

@@ -0,0 +1,87 @@
+import Tasks.*;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.Scanner;
+
+public class Loader {
+    private final String path = "data/duke.txt";
+
+    public TaskCollection loadTasks() {
+        TaskCollection tasks = new TaskCollection();
+        File file = new File(this.path);
+
+        try {
+            Scanner sc = new Scanner(file);
+            while (sc.hasNextLine()) {
+                String taskDetails = sc.nextLine();
+                Task newTask = createTask(taskDetails);
+                tasks.addTask(newTask);
+            }
+            return tasks;
+        } catch (FileNotFoundException e) {
+            return tasks;
+        }
+    }
+
+    public void saveTasks(TaskCollection tasks) {
+        try {
+            FileWriter writer = new FileWriter(this.path);
+
+            for (Task task : tasks.getListOfTasks()) {
+                writer.write(convertToSavableString(task));
+            }
+
+            writer.close();
+
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    private Task createTask(String taskDetails) {
+        String[] taskDetailsArray = taskDetails.split("\\|", 4);
+        String taskType = taskDetailsArray[0].trim();
+        String done = taskDetailsArray[1].trim();
+        String description = taskDetailsArray[2].trim();
+        String time = taskDetailsArray[3].trim();
+
+        Task newTask;
+        if (taskType.equals("T")) {
+            newTask = new ToDo(description);
+        } else if (taskType.equals("D")) {
+            newTask = new Deadline(description, time);
+        } else {
+            newTask = new Event(description, time);
+        }
+
+        if (done.equals("1")) {
+            newTask.markAsDone();
+        }
+
+        return newTask;
+    }
+
+    private String convertToSavableString(Task task) {
+        String time = "";
+        String taskType;
+
+        if (task instanceof Deadline) {
+            taskType = "D";
+            time = ((Deadline) task).getBy();
+        } else if (task instanceof Event) {
+            taskType = "E";
+            time = ((Event) task).getAt();
+        } else {
+            taskType = "T";
+        }
+
+        String done = task.isDone() ? "1" : "0";
+        String description = task.getDescription();
+
+        return taskType + " | " + done + " | " + description + " | " + time + "\n";
+    }
+}

src/main/java/TaskList.java src/main/java/TaskCollection.javasrc/main/java/TaskList.java renamed to src/main/java/TaskCollection.java

@@ -3,13 +3,17 @@
 
 import java.util.ArrayList;
 
-public class TaskList {
+public class TaskCollection {
     private final ArrayList<Task> tasks;
 
-    public TaskList() {
+    public TaskCollection() {
         tasks = new ArrayList<>();
     }
 
+    public ArrayList<Task> getListOfTasks() {
+        return this.tasks;
+    }
+
     public void addTask(Task task) {
         this.tasks.add(task);
     }

src/main/java/Tasks/Deadline.java

@@ -12,6 +12,10 @@ private String getByString() {
         return "(by: " + this.by + ")";
     }
 
+    public String getBy() {
+        return this.by;
+    }
+
     public String getStatusString() {
         return "[D]" + super.getStatusString() + " " + this.getByString();
     }

src/main/java/Tasks/Event.java

@@ -12,6 +12,10 @@ private String getAtString() {
         return "(at: " + this.at + ")";
     }
 
+    public String getAt() {
+        return this.at;
+    }
+
     public String getStatusString() {
         return "[E]" + super.getStatusString() + " " + this.getAtString();
     }

src/main/java/Tasks/Task.java

@@ -13,6 +13,10 @@ public void markAsDone() {
         this.isDone = true;
     }
 
+    public boolean isDone() {
+        return this.isDone;
+    }
+
     private String getStatusIcon() {
         return this.isDone ? "X" : " ";
     }