Merge pull request #93 from bryanyee33/86-undo-command

Add Undo command

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

@@ -20,8 +20,7 @@ public class Messages {
                 "Multiple values specified for the following single-valued field(s): ";
 
     public static final String MESSAGE_SHOWING_HELP = "Opened help window.";
-    public static final String MESSAGE_EXIT_ACKNOWLEDGEMENT = "Exiting Address Book as requested ...";
-
+    public static final String MESSAGE_EXITING = "Exiting Address Book as requested ...";
 
     /**
      * Returns an error message indicating the duplicate prefixes.

src/main/java/seedu/address/logic/commands/CommandType.java

@@ -52,6 +52,12 @@ public Command createCommand(String arguments) {
         public Command createCommand(String arguments) {
             return new HelpCommand();
         }
+    },
+    UNDO {
+        @Override
+        public Command createCommand(String arguments) {
+            return new UndoCommand();
+        }
     };
 
     public abstract Command createCommand(String arguments) throws IllegalArgumentException;

src/main/java/seedu/address/logic/commands/ExitCommand.java

@@ -12,7 +12,7 @@ public class ExitCommand extends Command {
 
     @Override
     public String execute(Model model) {
-        return Messages.MESSAGE_EXIT_ACKNOWLEDGEMENT;
+        return Messages.MESSAGE_EXITING;
     }
 
 }

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

@@ -0,0 +1,28 @@
+package seedu.address.logic.commands;
+
+import seedu.address.logic.commands.exceptions.CommandException;
+import seedu.address.model.Model;
+
+/**
+ * Undoes the latest modifying command
+ */
+public class UndoCommand extends Command {
+
+    public static final String COMMAND_WORD = "undo";
+
+    public static final String MESSAGE_USAGE = COMMAND_WORD + ": Undo the latest modifying command.\n"
+            + "Example: " + COMMAND_WORD;
+
+    public static final String MESSAGE_SUCCESS = "Undid the latest modifying command.";
+    public static final String MESSAGE_UNDO_EXCEPTION = "No modifying command to reverse.";
+
+    @Override
+    public String execute(Model model) throws CommandException {
+        if (!model.canUndo()) {
+            throw new CommandException(MESSAGE_UNDO_EXCEPTION);
+        }
+
+        model.undo();
+        return MESSAGE_SUCCESS;
+    }
+}

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

@@ -3,9 +3,13 @@
 import static java.util.Objects.requireNonNull;
 
 import java.util.List;
+import java.util.Stack;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
 
 import javafx.collections.ObservableList;
 import seedu.address.commons.util.ToStringBuilder;
+import seedu.address.model.exceptions.AddressBookUndoException;
 import seedu.address.model.person.Person;
 import seedu.address.model.person.UniquePersonList;
 
@@ -14,37 +18,54 @@
  * Duplicates are not allowed (by .isSamePerson comparison)
  */
 public class AddressBook implements ReadOnlyAddressBook {
+    private final UniquePersonList persons = new UniquePersonList();
+    @JsonIgnore
+    private final Stack<UniquePersonList> undoList = new Stack<>();
 
-    private final UniquePersonList persons;
-
-    /*
-     * The 'unusual' code block below is a non-static initialization block, sometimes used to avoid duplication
-     * between constructors. See https://docs.oracle.com/javase/tutorial/java/javaOO/initial.html
-     *
-     * Note that non-static init blocks are not recommended to use. There are other ways to avoid duplication
-     *   among constructors.
-     */
-    {
-        persons = new UniquePersonList();
+    public AddressBook() {
     }
 
-    public AddressBook() {}
-
     /**
      * Creates an AddressBook using the Persons in the {@code toBeCopied}
      */
     public AddressBook(ReadOnlyAddressBook toBeCopied) {
-        this();
-        resetData(toBeCopied);
+        persons.setPersons(toBeCopied.getPersonList());
     }
 
     //// list overwrite operations
 
+    /**
+     * Makes a copy of persons, and stores it in personsList.
+     */
+    private void save() {
+        UniquePersonList savedList = new UniquePersonList();
+        savedList.setPersons(persons);
+        undoList.add(savedList);
+    }
+
+    /**
+     * Returns true if there are states to reverse to.
+     */
+    public boolean canUndo() {
+        return !undoList.empty();
+    }
+
+    /**
+     * Undoes the latest change to address book.
+     */
+    public void undo() {
+        if (undoList.empty()) {
+            throw new AddressBookUndoException();
+        }
+        persons.setPersons(undoList.pop());
+    }
+
     /**
      * Replaces the contents of the person list with {@code persons}.
      * {@code persons} must not contain duplicate persons.
      */
     public void setPersons(List<Person> persons) {
+        save();
         this.persons.setPersons(persons);
     }
 
@@ -72,6 +93,7 @@ public boolean hasPerson(Person person) {
      * The person must not already exist in the address book.
      */
     public void addPerson(Person p) {
+        save();
         persons.add(p);
     }
 
@@ -82,7 +104,7 @@ public void addPerson(Person p) {
      */
     public void setPerson(Person target, Person editedPerson) {
         requireNonNull(editedPerson);
-
+        save();
         persons.setPerson(target, editedPerson);
     }
 
@@ -91,6 +113,7 @@ public void setPerson(Person target, Person editedPerson) {
      * {@code key} must exist in the address book.
      */
     public void removePerson(Person key) {
+        save();
         persons.remove(key);
     }
 

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

@@ -5,6 +5,7 @@
 
 import javafx.collections.ObservableList;
 import seedu.address.commons.core.GuiSettings;
+import seedu.address.model.exceptions.AddressBookUndoException;
 import seedu.address.model.person.Person;
 
 /**
@@ -52,6 +53,16 @@ public interface Model {
     /** Returns the AddressBook */
     ReadOnlyAddressBook getAddressBook();
 
+    /**
+     * Returns true if there are states to reverse to.
+     */
+    boolean canUndo();
+
+    /**
+     * Undoes the latest change to address book.
+     */
+    void undo() throws AddressBookUndoException;
+
     /**
      * Returns true if a person with the same identity as {@code person} exists in the address book.
      */

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

@@ -87,6 +87,16 @@ public ReadOnlyAddressBook getAddressBook() {
         return addressBook;
     }
 
+    @Override
+    public boolean canUndo() {
+        return addressBook.canUndo();
+    }
+
+    @Override
+    public void undo() {
+        addressBook.undo();
+    }
+
     @Override
     public boolean hasPerson(Person person) {
         requireNonNull(person);

src/main/java/seedu/address/model/exceptions/AddressBookUndoException.java

@@ -0,0 +1,10 @@
+package seedu.address.model.exceptions;
+
+/**
+ * Signals that there are no more states to undo to.
+ */
+public class AddressBookUndoException extends RuntimeException {
+    public AddressBookUndoException() {
+        super("There are no previous AddressBook states to return to.");
+    }
+}

src/main/java/seedu/address/storage/StorageManager.java

@@ -57,7 +57,7 @@ public Path getAddressBookFilePath() {
 
     @Override
     public Optional<ReadOnlyAddressBook> readAddressBook() throws DataLoadingException {
-        return readAddressBook(addressBookStorage.getAddressBookFilePath());
+        return readAddressBook(getAddressBookFilePath());
     }
 
     @Override

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

@@ -185,10 +185,10 @@ private String executeCommand(String commandText) throws CommandException, Parse
             throw e;
         }
 
-        if (commandResult.equals(Messages.MESSAGE_SHOWING_HELP)) {
+        if (commandResult == Messages.MESSAGE_SHOWING_HELP) {
             handleHelp();
         }
-        if (commandResult.equals(Messages.MESSAGE_EXIT_ACKNOWLEDGEMENT)) {
+        if (commandResult == Messages.MESSAGE_EXITING) {
             handleExit();
         }
         return commandResult;

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

@@ -345,6 +345,16 @@ public ReadOnlyAddressBook getAddressBook() {
             throw new AssertionError("This method should not be called.");
         }
 
+        @Override
+        public boolean canUndo() {
+            throw new AssertionError("This method should not be called.");
+        }
+
+        @Override
+        public void undo() {
+            throw new AssertionError("This method should not be called.");
+        }
+
         @Override
         public boolean hasPerson(Person person) {
             throw new AssertionError("This method should not be called.");

src/test/java/seedu/address/logic/commands/ExitCommandTest.java

@@ -14,6 +14,6 @@ public class ExitCommandTest {
 
     @Test
     public void execute_exit_success() {
-        assertCommandSuccess(new ExitCommand(), model, Messages.MESSAGE_EXIT_ACKNOWLEDGEMENT, expectedModel);
+        assertCommandSuccess(new ExitCommand(), model, Messages.MESSAGE_EXITING, expectedModel);
     }
 }

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

@@ -0,0 +1,77 @@
+package seedu.address.logic.commands;
+
+import static seedu.address.logic.commands.CommandTestUtil.assertCommandFailure;
+import static seedu.address.logic.commands.CommandTestUtil.assertCommandSuccess;
+import static seedu.address.testutil.TypicalIndexes.INDEX_FIRST_PERSON;
+import static seedu.address.testutil.TypicalPersons.getTypicalAddressBook;
+
+import org.junit.jupiter.api.Test;
+
+import seedu.address.model.AddressBook;
+import seedu.address.model.Model;
+import seedu.address.model.ModelManager;
+import seedu.address.model.UserPrefs;
+import seedu.address.model.person.Person;
+import seedu.address.testutil.PersonBuilder;
+
+public class UndoCommandTest {
+
+    private Model model = new ModelManager(getTypicalAddressBook(), new UserPrefs());
+
+    @Test
+    public void execute_multipleInvalidUndo_throwsCommandException() {
+        UndoCommand undoCommand = new UndoCommand();
+
+        String expectedMessage = UndoCommand.MESSAGE_UNDO_EXCEPTION;
+
+        assertCommandFailure(undoCommand, model, expectedMessage);
+        assertCommandFailure(undoCommand, model, expectedMessage);
+        assertCommandFailure(undoCommand, model, expectedMessage);
+    }
+
+    @Test
+    public void execute_oneUndo_success() {
+        UndoCommand undoCommand = new UndoCommand();
+
+        String expectedMessage = UndoCommand.MESSAGE_SUCCESS;
+
+        Person personToDelete = model.getFilteredPersonList().get(INDEX_FIRST_PERSON.getZeroBased());
+        model.deletePerson(personToDelete);
+        ModelManager expectedModel = new ModelManager(getTypicalAddressBook(), new UserPrefs());
+
+        assertCommandSuccess(undoCommand, model, expectedMessage, expectedModel);
+    }
+
+    @Test
+    public void execute_multipleUndo_success() {
+        UndoCommand undoCommand = new UndoCommand();
+
+        String expectedMessage = UndoCommand.MESSAGE_SUCCESS;
+        ModelManager expectedModelBase = new ModelManager(getTypicalAddressBook(), new UserPrefs());
+
+        // delete
+        Person personToDelete = model.getFilteredPersonList().get(INDEX_FIRST_PERSON.getZeroBased());
+        ModelManager expectedModelDelete = new ModelManager(new AddressBook(model.getAddressBook()), new UserPrefs());
+        expectedModelDelete.deletePerson(personToDelete);
+        model.deletePerson(personToDelete);
+
+        // edit
+        Person editedPerson = new PersonBuilder().build();
+        ModelManager expectedModelEdit = new ModelManager(new AddressBook(model.getAddressBook()), new UserPrefs());
+        expectedModelEdit.setPerson(model.getFilteredPersonList().get(0), editedPerson);
+        editedPerson = new PersonBuilder().build();
+        model.setPerson(model.getFilteredPersonList().get(0), editedPerson);
+
+        // clear
+        model.setAddressBook(new AddressBook());
+
+        // undo clear
+        assertCommandSuccess(undoCommand, model, expectedMessage, expectedModelEdit);
+        // undo edit
+        assertCommandSuccess(undoCommand, model, expectedMessage, expectedModelDelete);
+        // undo delete
+        assertCommandSuccess(undoCommand, model, expectedMessage, expectedModelBase);
+        // no more to undo
+        assertCommandFailure(undoCommand, model, UndoCommand.MESSAGE_UNDO_EXCEPTION);
+    }
+}

src/test/java/seedu/address/model/AddressBookTest.java

@@ -1,5 +1,6 @@
 package seedu.address.model;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -18,6 +19,7 @@
 
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
+import seedu.address.model.exceptions.AddressBookUndoException;
 import seedu.address.model.person.Person;
 import seedu.address.model.person.exceptions.DuplicatePersonException;
 import seedu.address.testutil.PersonBuilder;
@@ -31,6 +33,17 @@ public void constructor() {
         assertEquals(Collections.emptyList(), addressBook.getPersonList());
     }
 
+    @Test
+    public void undo_undoRemaining_success() {
+        addressBook.addPerson(ALICE);
+        assertDoesNotThrow(addressBook::undo);
+    }
+
+    @Test
+    public void undo_noUndoRemaining_throwsAddressBookUndoException() {
+        assertThrows(AddressBookUndoException.class, addressBook::undo);
+    }
+
     @Test
     public void resetData_null_throwsNullPointerException() {
         assertThrows(NullPointerException.class, () -> addressBook.resetData(null));