Merge branch 'undo-command-a'

src/main/java/igrad/MainApp.java

@@ -56,7 +56,10 @@ public void init() throws Exception {
 
         UserPrefsStorage userPrefsStorage = new JsonUserPrefsStorage(config.getUserPrefsFilePath());
         ReadOnlyUserPrefs userPrefs = initPrefs(userPrefsStorage);
-        CourseBookStorage courseBookStorage = new JsonCourseBookStorage(userPrefs.getCourseBookFilePath());
+        CourseBookStorage courseBookStorage = new JsonCourseBookStorage(
+            userPrefs.getCourseBookFilePath(),
+            userPrefs.getBackupCourseBookFilePath()
+        );
         storage = new StorageManager(courseBookStorage, userPrefsStorage);
 
         initLogging(config);

src/main/java/igrad/logic/LogicManager.java

@@ -10,6 +10,7 @@
 import igrad.logic.commands.CommandResult;
 import igrad.logic.commands.CourseAddCommand;
 import igrad.logic.commands.SelectAvatarCommand;
+import igrad.logic.commands.UndoCommand;
 import igrad.logic.commands.exceptions.CommandException;
 import igrad.logic.parser.CourseBookParser;
 import igrad.logic.parser.exceptions.ParseException;
@@ -78,9 +79,19 @@ public CommandResult execute(String commandText) throws CommandException,
         ParseException, IOException, ServiceException {
         logger.info("----------------[USER COMMAND][" + commandText + "]");
 
+
         CommandResult commandResult;
         Command command = courseBookParser.parseCommand(commandText);
 
+        if (!(command instanceof UndoCommand)) {
+            try {
+                // First, load current state into backup
+                storage.saveBackupCourseBook(model.getCourseBook());
+            } catch (IOException ioe) {
+                throw new CommandException(FILE_OPS_ERROR_MESSAGE + ioe, ioe);
+            }
+        }
+
         commandResult = command.execute(model);
 
         try {

src/main/java/igrad/logic/commands/UndoCommand.java

@@ -0,0 +1,47 @@
+package igrad.logic.commands;
+
+import java.util.Optional;
+
+import igrad.commons.exceptions.DataConversionException;
+import igrad.logic.commands.exceptions.CommandException;
+import igrad.model.Model;
+import igrad.model.ReadOnlyCourseBook;
+import igrad.storage.JsonCourseBookStorage;
+
+/**
+ * Undoes the previous action taken.
+ */
+public class UndoCommand extends Command {
+
+    public static final String COMMAND_WORD = "undo";
+
+    public static final String MESSAGE_USAGE = COMMAND_WORD + ": Undoes latest action.\n"
+        + "Example: " + COMMAND_WORD;
+
+    public static final String MESSAGE_SUCCESS = "Undid last command.";
+    public static final String MESSAGE_ERROR = "Unable to undo the last comamand.";
+
+    @Override
+    public CommandResult execute(Model model) throws CommandException {
+
+        JsonCourseBookStorage courseBookStorage = new JsonCourseBookStorage(
+            model.getCourseBookFilePath(),
+            model.getBackupCourseBookFilePath()
+        );
+
+        try {
+            Optional<ReadOnlyCourseBook> backupCourseBook = courseBookStorage.readBackupCourseBook();
+
+            if (backupCourseBook.isPresent()) {
+                model.setCourseBook(backupCourseBook.get());
+            } else {
+                throw new CommandException(MESSAGE_ERROR);
+            }
+
+        } catch (DataConversionException e) {
+            throw new CommandException(MESSAGE_ERROR);
+        }
+
+        return new CommandResult(MESSAGE_SUCCESS, false, false, false);
+    }
+}

src/main/java/igrad/logic/parser/CourseBookParser.java

@@ -20,6 +20,7 @@
 import igrad.logic.commands.ModuleDeleteCommand;
 import igrad.logic.commands.ModuleEditCommand;
 import igrad.logic.commands.SelectAvatarCommand;
+import igrad.logic.commands.UndoCommand;
 import igrad.logic.commands.requirement.RequirementAddCommand;
 import igrad.logic.commands.requirement.RequirementDeleteCommand;
 import igrad.logic.commands.requirement.RequirementEditCommand;
@@ -133,6 +134,9 @@ public Command parseCommand(String userInput) throws ParseException, IOException
         case ExportCommand.COMMAND_WORD:
             return new ExportCommand();
 
+        case UndoCommand.COMMAND_WORD:
+            return new UndoCommand();
+
         case CourseAddCommand.COMMAND_WORD:
             return new CourseAddCommandParser().parse(arguments);
 

src/main/java/igrad/model/Model.java

@@ -51,6 +51,12 @@ public interface Model {
      */
     Path getCourseBookFilePath();
 
+    /**
+     * Returns the user prefs' backup course book file path.
+     */
+    Path getBackupCourseBookFilePath();
+
+
     /**
      * Sets the user prefs' course book file path.
      */

src/main/java/igrad/model/ModelManager.java

@@ -80,6 +80,11 @@ public Path getCourseBookFilePath() {
         return userPrefs.getCourseBookFilePath();
     }
 
+    @Override
+    public Path getBackupCourseBookFilePath() {
+        return userPrefs.getBackupCourseBookFilePath();
+    }
+
     @Override
     public void setCourseBookFilePath(Path courseBookFilePath) {
         requireNonNull(courseBookFilePath);

src/main/java/igrad/model/ReadOnlyUserPrefs.java

@@ -14,5 +14,7 @@ public interface ReadOnlyUserPrefs {
 
     Path getCourseBookFilePath();
 
+    Path getBackupCourseBookFilePath();
+
     Avatar getAvatar();
 }

src/main/java/igrad/model/UserPrefs.java

@@ -16,6 +16,7 @@ public class UserPrefs implements ReadOnlyUserPrefs {
 
     private GuiSettings guiSettings = new GuiSettings();
     private Path courseBookFilePath = Paths.get("data", "coursebook.json");
+    private Path backupCourseBookFilePath = Paths.get("data", "backup_coursebook.json");
     private Avatar avatar = new Avatar();
 
     /**
@@ -39,6 +40,7 @@ public void resetData(ReadOnlyUserPrefs newUserPrefs) {
         requireNonNull(newUserPrefs);
         setGuiSettings(newUserPrefs.getGuiSettings());
         setCourseBookFilePath(newUserPrefs.getCourseBookFilePath());
+        setBackupCourseBookFilePath(newUserPrefs.getBackupCourseBookFilePath());
         setAvatar(newUserPrefs.getAvatar());
     }
 
@@ -55,11 +57,21 @@ public Path getCourseBookFilePath() {
         return courseBookFilePath;
     }
 
+    @Override
+    public Path getBackupCourseBookFilePath() {
+        return backupCourseBookFilePath;
+    }
+
     public void setCourseBookFilePath(Path courseBookFilePath) {
         requireNonNull(courseBookFilePath);
         this.courseBookFilePath = courseBookFilePath;
     }
 
+    public void setBackupCourseBookFilePath(Path backupCourseBookFilePath) {
+        requireNonNull(backupCourseBookFilePath);
+        this.backupCourseBookFilePath = backupCourseBookFilePath;
+    }
+
     public Avatar getAvatar() {
         return avatar;
     }
@@ -82,6 +94,7 @@ public boolean equals(Object other) {
 
         return guiSettings.equals(o.guiSettings)
             && courseBookFilePath.equals(o.courseBookFilePath)
+            && backupCourseBookFilePath.equals(o.backupCourseBookFilePath)
             && avatar.equals(o.avatar);
     }
 
@@ -95,6 +108,7 @@ public String toString() {
         StringBuilder sb = new StringBuilder();
         sb.append("Gui Settings : " + guiSettings);
         sb.append("\nLocal data file location : " + courseBookFilePath);
+        sb.append("\nBackup Local data file location : " + backupCourseBookFilePath);
         sb.append("\nAvatar : " + avatar);
         return sb.toString();
     }

src/main/java/igrad/model/util/SampleDataUtil.java

@@ -53,6 +53,10 @@ public static Path getSampleCourseBookFilePath() {
         return Paths.get("data", "coursebook.json");
     }
 
+    public static Path getSampleBackupCourseBookFilePath() {
+        return Paths.get("data", "backup_coursebook.json");
+    }
+
     public static ReadOnlyCourseBook getSampleCourseBook() {
         CourseBook sampleCourseBook = new CourseBook();
         for (Module sampleModule : getSamplePersons()) {
@@ -71,6 +75,7 @@ public static UserPrefs getSampleUserPrefs() {
 
         sampleUserPrefs.setGuiSettings(new GuiSettings());
         sampleUserPrefs.setCourseBookFilePath(getSampleCourseBookFilePath());
+        sampleUserPrefs.setBackupCourseBookFilePath(getSampleBackupCourseBookFilePath());
         sampleUserPrefs.setAvatar(getSampleAvatar());
 
         return sampleUserPrefs;

src/main/java/igrad/storage/CourseBookStorage.java

@@ -18,6 +18,20 @@ public interface CourseBookStorage {
      */
     Path getCourseBookFilePath();
 
+    /**
+     * Returns the file path of the backup data file.
+     */
+    Path getBackupCourseBookFilePath();
+
+    /**
+     * Returns backup CourseBook data as a {@link ReadOnlyCourseBook}.
+     * Returns {@code Optional.empty()} if storage file is not found.
+     *
+     * @throws DataConversionException if the data in storage is not in the expected format.
+     * @throws IOException             if there was any problem when reading from the storage.
+     */
+    Optional<ReadOnlyCourseBook> readBackupCourseBook() throws DataConversionException, IOException;
+
     /**
      * Returns CourseBook data as a {@link ReadOnlyCourseBook}.
      * Returns {@code Optional.empty()} if storage file is not found.
@@ -45,4 +59,9 @@ public interface CourseBookStorage {
      */
     void saveCourseBook(ReadOnlyCourseBook courseBook, Path filePath) throws IOException;
 
+    /**
+     * @see #saveBackupCourseBook(ReadOnlyCourseBook)
+     */
+    void saveBackupCourseBook(ReadOnlyCourseBook courseBook) throws IOException;
+
 }

src/main/java/igrad/storage/JsonCourseBookStorage.java

@@ -22,6 +22,12 @@ public class JsonCourseBookStorage implements CourseBookStorage {
     private static final Logger logger = LogsCenter.getLogger(JsonCourseBookStorage.class);
 
     private Path filePath;
+    private Path backupFilePath;
+
+    public JsonCourseBookStorage(Path filePath, Path backupFilePath) {
+        this.filePath = filePath;
+        this.backupFilePath = backupFilePath;
+    }
 
     public JsonCourseBookStorage(Path filePath) {
         this.filePath = filePath;
@@ -31,6 +37,16 @@ public Path getCourseBookFilePath() {
         return filePath;
     }
 
+    @Override
+    public Path getBackupCourseBookFilePath() {
+        return backupFilePath;
+    }
+
+    @Override
+    public Optional<ReadOnlyCourseBook> readBackupCourseBook() throws DataConversionException {
+        return readCourseBook(backupFilePath);
+    }
+
     @Override
     public Optional<ReadOnlyCourseBook> readCourseBook() throws DataConversionException {
         return readCourseBook(filePath);
@@ -79,4 +95,9 @@ public void saveCourseBook(ReadOnlyCourseBook courseBook, Path filePath) throws
         JsonUtil.saveJsonFile(new JsonSerializableCourseBook(courseBook), filePath);
     }
 
+    @Override
+    public void saveBackupCourseBook(ReadOnlyCourseBook courseBook) throws IOException {
+        saveCourseBook(courseBook, backupFilePath);
+    }
+
 }

src/main/java/igrad/storage/Storage.java

@@ -26,6 +26,12 @@ public interface Storage extends CourseBookStorage, UserPrefsStorage {
     @Override
     Optional<ReadOnlyCourseBook> readCourseBook() throws DataConversionException, IOException;
 
+    @Override
+    Optional<ReadOnlyCourseBook> readBackupCourseBook() throws DataConversionException, IOException;
+
     @Override
     void saveCourseBook(ReadOnlyCourseBook courseBook) throws IOException;
+
+    @Override
+    void saveBackupCourseBook(ReadOnlyCourseBook courseBook) throws IOException;
 }

src/main/java/igrad/storage/StorageManager.java

@@ -51,6 +51,11 @@ public Path getCourseBookFilePath() {
         return courseBookStorage.getCourseBookFilePath();
     }
 
+    @Override
+    public Path getBackupCourseBookFilePath() {
+        return courseBookStorage.getBackupCourseBookFilePath();
+    }
+
     @Override
     public Optional<ReadOnlyCourseBook> readCourseBook() throws DataConversionException, IOException {
         return readCourseBook(courseBookStorage.getCourseBookFilePath());
@@ -62,11 +67,22 @@ public Optional<ReadOnlyCourseBook> readCourseBook(Path filePath) throws DataCon
         return courseBookStorage.readCourseBook(filePath);
     }
 
+    @Override
+    public Optional<ReadOnlyCourseBook> readBackupCourseBook() throws DataConversionException, IOException {
+        return readCourseBook(courseBookStorage.getBackupCourseBookFilePath());
+    }
+
+    @Override
+    public void saveBackupCourseBook(ReadOnlyCourseBook courseBook) throws IOException {
+        saveCourseBook(courseBook, courseBookStorage.getBackupCourseBookFilePath());
+    }
+
     @Override
     public void saveCourseBook(ReadOnlyCourseBook courseBook) throws IOException {
         saveCourseBook(courseBook, courseBookStorage.getCourseBookFilePath());
     }
 
+
     @Override
     public void saveCourseBook(ReadOnlyCourseBook courseBook, Path filePath) throws IOException {
         logger.fine("Attempting to write to data file: " + filePath);

src/main/resources/view/MainWindow.fxml

@@ -13,7 +13,7 @@
 <?import javafx.scene.layout.VBox?>
 <?import javafx.stage.Stage?>
 
-<fx:root minHeight="750.0" minWidth="800.0" onCloseRequest="#handleExit" title="iGrad" type="javafx.stage.Stage" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1">
+<fx:root minHeight="800.0" minWidth="800.0" onCloseRequest="#handleExit" title="iGrad" type="javafx.stage.Stage" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1">
     <icons>
         <Image url="@/images/iGrad_Shibu.png" />
     </icons>

src/test/java/igrad/logic/commands/AddCommandTest.java

@@ -108,6 +108,11 @@ public Path getCourseBookFilePath() {
             throw new AssertionError("This method should not be called.");
         }
 
+        @Override
+        public Path getBackupCourseBookFilePath() {
+            throw new AssertionError("This method should not be called.");
+        }
+
         @Override
         public void setCourseBookFilePath(Path courseBookFilePath) {
             throw new AssertionError("This method should not be called.");