Merge pull request #74 from dedsecrattle/features/undo

Implement Undo Command

src/main/java/seedu/edulink/logic/LogicManager.java

@@ -49,7 +49,6 @@ public CommandResult execute(String commandText) throws CommandException, ParseE
         CommandResult commandResult;
         Command command = addressBookParser.parseCommand(commandText);
         commandResult = command.execute(model);
-
         try {
             storage.saveAddressBook(model.getAddressBook());
         } catch (AccessDeniedException e) {

src/main/java/seedu/edulink/logic/Messages.java

@@ -16,6 +16,7 @@ public class Messages {
     public static final String MESSAGE_INVALID_COMMAND_FORMAT = "Invalid command format! \n%1$s";
     public static final String MESSAGE_INVALID_PERSON_DISPLAYED_INDEX = "The student index provided is invalid";
     public static final String MESSAGE_STUDENT_NOT_FOUND = "Student with given ID does not exist!";
+    public static final String MESSAGE_NO_HISTORY_FOUND = "No History available to Undo";
     public static final String MESSAGE_PERSONS_LISTED_OVERVIEW = "%1$d persons listed!";
     public static final String MESSAGE_DUPLICATE_FIELDS =
         "Multiple values specified for the following single-valued field(s): ";

src/main/java/seedu/edulink/logic/commands/UndoCommand.java

@@ -0,0 +1,25 @@
+package seedu.edulink.logic.commands;
+
+import seedu.edulink.logic.Messages;
+import seedu.edulink.logic.commands.exceptions.CommandException;
+import seedu.edulink.model.Model;
+
+/**
+ * Undo the most recent command and revert back to previous state
+ */
+public class UndoCommand extends Command {
+    public static final String COMMAND_WORD = "undo";
+    public static final String MESSAGE_USAGE = "Usage: " + COMMAND_WORD;
+    public static final String MESSAGE_SUCCESS = "Undo Command done Successfully";
+
+    @Override
+    public CommandResult execute(Model model) throws CommandException {
+        if (model.resetToPreviousState()) {
+            model.updateFilteredPersonList(Model.PREDICATE_SHOW_ALL_PERSONS);
+            return new CommandResult(MESSAGE_SUCCESS);
+        } else {
+            throw new CommandException(Messages.MESSAGE_NO_HISTORY_FOUND);
+        }
+    }
+
+}

src/main/java/seedu/edulink/logic/parser/AddressBookParser.java

@@ -18,6 +18,7 @@
 import seedu.edulink.logic.commands.HelpCommand;
 import seedu.edulink.logic.commands.ListCommand;
 import seedu.edulink.logic.commands.TagCommand;
+import seedu.edulink.logic.commands.UndoCommand;
 import seedu.edulink.logic.parser.exceptions.ParseException;
 
 /**
@@ -78,9 +79,11 @@ public Command parseCommand(String userInput) throws ParseException {
         case HelpCommand.COMMAND_WORD:
             return new HelpCommand();
 
+        case UndoCommand.COMMAND_WORD:
+            return new UndoCommand();
+
         case TagCommand.COMMAND_WORD:
             return new TagCommandParser().parse(arguments);
-
         default:
             logger.finer("This user input caused a ParseException: " + userInput);
             throw new ParseException(MESSAGE_UNKNOWN_COMMAND);

src/main/java/seedu/edulink/model/AddressBook.java

@@ -83,7 +83,6 @@ public void addPerson(Student p) {
      */
     public void setPerson(Student target, Student editedStudent) {
         requireNonNull(editedStudent);
-
         persons.setPerson(target, editedStudent);
     }
 
@@ -128,4 +127,5 @@ public boolean equals(Object other) {
     public int hashCode() {
         return persons.hashCode();
     }
+
 }

src/main/java/seedu/edulink/model/Model.java

@@ -91,4 +91,6 @@ public interface Model {
      * @throws NullPointerException if {@code predicate} is null.
      */
     void updateFilteredPersonList(Predicate<Student> predicate);
+
+    boolean resetToPreviousState();
 }

src/main/java/seedu/edulink/model/ModelManager.java

@@ -4,6 +4,9 @@
 import static seedu.edulink.commons.util.CollectionUtil.requireAllNonNull;
 
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Stack;
 import java.util.function.Predicate;
 import java.util.logging.Logger;
 
@@ -22,6 +25,7 @@ public class ModelManager implements Model {
     private final AddressBook addressBook;
     private final UserPrefs userPrefs;
     private final FilteredList<Student> filteredStudents;
+    private final Stack<List<Student>> previousStates;
 
     /**
      * Initializes a ModelManager with the given addressBook and userPrefs.
@@ -34,6 +38,7 @@ public ModelManager(ReadOnlyAddressBook addressBook, ReadOnlyUserPrefs userPrefs
         this.addressBook = new AddressBook(addressBook);
         this.userPrefs = new UserPrefs(userPrefs);
         filteredStudents = new FilteredList<>(this.addressBook.getPersonList());
+        previousStates = new Stack<>();
     }
 
     public ModelManager() {
@@ -95,19 +100,24 @@ public boolean hasPerson(Student student) {
 
     @Override
     public void deletePerson(Student target) {
+        List<Student> prev = new ArrayList<>(addressBook.getPersonList());
+        previousStates.push(prev);
         addressBook.removePerson(target);
     }
 
     @Override
     public void addPerson(Student student) {
+        List<Student> prev = new ArrayList<>(addressBook.getPersonList());
+        previousStates.push(prev);
         addressBook.addPerson(student);
         updateFilteredPersonList(PREDICATE_SHOW_ALL_PERSONS);
     }
 
     @Override
     public void setPerson(Student target, Student editedStudent) {
+        List<Student> prev = new ArrayList<>(addressBook.getPersonList());
+        previousStates.push(prev);
         requireAllNonNull(target, editedStudent);
-
         addressBook.setPerson(target, editedStudent);
     }
 
@@ -128,6 +138,16 @@ public void updateFilteredPersonList(Predicate<Student> predicate) {
         filteredStudents.setPredicate(predicate);
     }
 
+    @Override
+    public boolean resetToPreviousState() {
+        if (previousStates.isEmpty()) {
+            return false;
+        } else {
+            addressBook.setPersons(previousStates.pop());
+            return true;
+        }
+    }
+
     @Override
     public boolean equals(Object other) {
         if (other == this) {

src/main/java/seedu/edulink/ui/MainWindow.java

@@ -186,7 +186,6 @@ private CommandResult executeCommand(String commandText) throws CommandException
             if (commandResult.isExit()) {
                 handleExit();
             }
-
             return commandResult;
         } catch (CommandException | ParseException e) {
             logger.info("An error occurred while executing command: " + commandText);

src/main/java/seedu/edulink/ui/UiManager.java

@@ -32,6 +32,7 @@ public UiManager(Logic logic) {
         this.logic = logic;
     }
 
+
     @Override
     public void start(Stage primaryStage) {
         logger.info("Starting UI...");

src/test/java/seedu/edulink/logic/commands/AddCommandTest.java

@@ -157,6 +157,11 @@ public ObservableList<Student> getFilteredPersonList() {
         public void updateFilteredPersonList(Predicate<Student> predicate) {
             throw new AssertionError("This method should not be called.");
         }
+
+        @Override
+        public boolean resetToPreviousState() {
+            throw new AssertionError("This method should not be called.");
+        }
     }
 
     /**

src/test/java/seedu/edulink/logic/commands/UndoCommandTest.java

@@ -0,0 +1,45 @@
+package seedu.edulink.logic.commands;
+
+import static seedu.edulink.logic.commands.CommandTestUtil.assertCommandFailure;
+import static seedu.edulink.logic.commands.CommandTestUtil.assertCommandSuccess;
+
+import org.junit.jupiter.api.Test;
+
+import seedu.edulink.logic.Messages;
+import seedu.edulink.model.Model;
+import seedu.edulink.model.ModelManager;
+import seedu.edulink.testutil.TypicalPersons;
+
+public class UndoCommandTest {
+    private Model model = new ModelManager();
+
+    @Test
+    public void undo_command_failure() {
+        assertCommandFailure(new UndoCommand(), model, Messages.MESSAGE_NO_HISTORY_FOUND);
+    }
+
+    @Test
+    public void add_success() {
+        model.addPerson(TypicalPersons.ALICE);
+        Model expected = new ModelManager();
+        assertCommandSuccess(new UndoCommand(), model, new CommandResult(UndoCommand.MESSAGE_SUCCESS), expected);
+    }
+
+    @Test
+    public void edit_success() {
+        model.addPerson(TypicalPersons.ALICE);
+        model.setPerson(TypicalPersons.ALICE, TypicalPersons.BOB);
+        Model expected = new ModelManager();
+        expected.addPerson(TypicalPersons.ALICE);
+        assertCommandSuccess(new UndoCommand(), model, new CommandResult(UndoCommand.MESSAGE_SUCCESS), expected);
+    }
+
+    @Test
+    public void delete_success() {
+        model.addPerson(TypicalPersons.ALICE);
+        model.deletePerson(TypicalPersons.ALICE);
+        Model expected = new ModelManager();
+        expected.addPerson(TypicalPersons.ALICE);
+        assertCommandSuccess(new UndoCommand(), model, new CommandResult(UndoCommand.MESSAGE_SUCCESS), expected);
+    }
+}

src/test/java/seedu/edulink/logic/parser/AddressBookParserTest.java

@@ -20,6 +20,7 @@
 import seedu.edulink.logic.commands.FindCommand;
 import seedu.edulink.logic.commands.HelpCommand;
 import seedu.edulink.logic.commands.ListCommand;
+import seedu.edulink.logic.commands.UndoCommand;
 import seedu.edulink.logic.parser.exceptions.ParseException;
 import seedu.edulink.model.student.IdAndNameContainsQueryIdAndNamePredicate;
 import seedu.edulink.model.student.IdContainsQueryIdPredicate;
@@ -89,6 +90,12 @@ public void parseCommand_help() throws Exception {
         assertTrue(parser.parseCommand(HelpCommand.COMMAND_WORD + " 3") instanceof HelpCommand);
     }
 
+    @Test
+    public void parseCommand_undo() throws Exception {
+        assertTrue(parser.parseCommand(UndoCommand.COMMAND_WORD) instanceof UndoCommand);
+        assertTrue(parser.parseCommand(UndoCommand.COMMAND_WORD + " 3") instanceof UndoCommand);
+    }
+
     @Test
     public void parseCommand_list() throws Exception {
         assertTrue(parser.parseCommand(ListCommand.COMMAND_WORD) instanceof ListCommand);

src/test/java/seedu/edulink/model/ModelManagerTest.java

@@ -92,6 +92,14 @@ public void getFilteredPersonList_modifyList_throwsUnsupportedOperationException
         assertThrows(UnsupportedOperationException.class, () -> modelManager.getFilteredPersonList().remove(0));
     }
 
+    @Test
+    public void resetToPreviousState() {
+        Model testModel = new ModelManager();
+        assertFalse(testModel.resetToPreviousState());
+        testModel.addPerson(ALICE);
+        assertTrue(testModel.resetToPreviousState());
+    }
+
     @Test
     public void equals() {
         AddressBook addressBook = new AddressBookBuilder().withPerson(ALICE).withPerson(BENSON).build();