Merge pull request #238

Correct bugs in undo command and update its UML in DG

docs/DeveloperGuide.md

@@ -134,7 +134,7 @@ The structure is simple:
 
 The `Model` component,
 
-* stores the address book data i.e., all `Person` objects (which are contained in a `UniquePersonList` object).
+* stores the CampusConnect data i.e., all `Person` objects (which are contained in a `UniquePersonList` object).
 * stores the currently 'selected' `Person` objects (e.g., results of a search query) as a separate _filtered_ list which is exposed to outsiders as an unmodifiable `ObservableList<Person>` that can be 'observed' e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
 * stores a `UserPref` object that represents the user’s preferences. This is exposed to the outside as a `ReadOnlyUserPref` objects.
 * does not depend on any of the other three components (as the `Model` represents data entities of the domain, they should make sense on their own without depending on other components)
@@ -155,7 +155,7 @@ The `Model` component,
 <puml src="diagrams/StorageClassDiagram.puml" width="550" />
 
 The `Storage` component,
-* can save both address book data and user preference data in JSON format, and read them back into corresponding objects.
+* can save both CampusConnect data and user preference data in JSON format, and read them back into corresponding objects.
 * inherits from both `CampusConnectStorage` and `UserPrefStorage`, which means it can be treated as either one (if only the functionality of only one is needed).
 * depends on some classes in the `Model` component (because the `Storage` component's job is to save/retrieve objects that belong to the `Model`)
 
@@ -169,16 +169,16 @@ Classes used by multiple components are in the `seedu.address.commons` package.
 
 This section describes some noteworthy details on how certain features are implemented.
 
-### \[Proposed\] Undo/redo feature
+### Undo/redo feature
 
 #### Proposed Implementation
 
 The proposed undo/redo mechanism is facilitated by `VersionedCampusConnect`. It extends `CampusConnect` with an undo/redo history, stored internally as an `history` and `future`. Additionally, it implements the following operations:
 
-* `VersionedCampusConnect#saveCurrentData()` — Saves the current address book state in its future.
-*  `VersionedCampusConnect#saveOldData()` — Saves the current address book state in its history.
-* `VersionedCampusConnect#extractOldData()` — Restores the previous address book state from its history.
-* `VersionedCampusConnect#extractUndoneData()` — Restores a previously undone address book state from its history.
+* `VersionedCampusConnect#saveCurrentData()` — Saves the current CampusConnect state in its future.
+*  `VersionedCampusConnect#saveOldData()` — Saves the current CampusConnect state in its history.
+* `VersionedCampusConnect#extractOldData()` — Restores the previous CampusConnect state from its history.
+* `VersionedCampusConnect#extractUndoneData()` — Restores a previously undone CampusConnect state from its history.
 
 These operations are exposed in the `Model` interface as `Model#saveCurrentCampusConnect()`, `Model#undoCampusConnect()` and `Model#redoCampusConnect()` respectively.
 
@@ -188,7 +188,7 @@ Step 1. The user launches the application for the first time. The `VersionedCamp
 
 <puml src="diagrams/UndoRedoState0.puml" alt="UndoRedoState0" />
 
-Step 2. The user executes `delete 5` command to delete the 5th person in the address book. The `delete` command calls `Model#saveCurrentCampusConnect()`, causing the modified state of the CampusConnect after the `delete 5` command executes to be displayed and the old state of CampusConnect to be saved to the history.
+Step 2. The user executes `delete 5` command to delete the 5th person in the CampusConnect. The `delete` command calls `Model#saveCurrentCampusConnect()`, causing the modified state of the CampusConnect after the `delete 5` command executes to be displayed and the old state of CampusConnect to be saved to the history.
 
 <puml src="diagrams/UndoRedoState1.puml" alt="UndoRedoState1" />
 
@@ -236,7 +236,7 @@ The `redo` command does the opposite — it calls `Model#redoCampusConnect()
 
 </box>
 
-Step 5. The user then decides to execute the command `list`. Commands that do not modify the address book, such as `list`, will usually not call `Model#commitCampusConnect()`, `Model#undoCampusConnect()` or `Model#redoCampusConnect()`. Thus, the `campusConnectStateList` remains unchanged.
+Step 5. The user then decides to execute the command `list`. Commands that do not modify the CampusConnect, such as `list`, will usually not call `Model#saveCurrentCampusConnect()`, `Model#undoCampusConnect()` or `Model#redoCampusConnect()`. Thus, the `history` and `future` remain unchanged.
 
 <puml src="diagrams/UndoRedoState4.puml" alt="UndoRedoState4" />
 
@@ -252,7 +252,7 @@ The following activity diagram summarizes what happens when a user executes a ne
 
 **Aspect: How undo & redo executes:**
 
-* **Alternative 1 (current choice):** Saves the entire address book.
+* **Alternative 1 (current choice):** Saves the entire CampusConnect.
   * Pros: Easy to implement.
   * Cons: May have performance issues in terms of memory usage.
 
@@ -302,19 +302,19 @@ _{Explain here how the data archiving feature will be implemented}_
 
 Priorities: High (must have) - `* * *`, Medium (nice to have) - `* *`, Low (unlikely to have) - `*`
 
-| Priority | As a …​                 | I want to …​                                                    | So that I can…​                                                               |
-|----------|-------------------------|-----------------------------------------------------------------|-------------------------------------------------------------------------------|
-| `* * *`  | new user                | see usage instructions                                          | refer to instructions when I forget how to use the App                        |
-| `* * *`  | user                    | add a new contact                                               | easily connect with them                                                      |
-| `* * *`  | user                    | delete a contact                                                | remove entries that I no longer need                                          |
-| `* * *`  | user                    | find a person by name                                           | locate details of persons without having to go through the entire list        |
-| `* *`    | user                    | update my contacts information                                  | always keep an updated version of contact information                         |
-| `*`      | user with many contacts | search contacts by name                                         | locate a contact easily                                                       |
-| `*`      | user                    | add a tag information to contacts                               | easily locate and connect with individuals such as classmates or club members |
-| `*`      | student                 | filter contacts by tags such as "group project" or "internship" | easily access related contacts                                                |
-| `*`      | user                    | undo my last action                                             | prevent the accidental deletion of all my contacts                            |
-
-*{More to be added}*
+| Priority | As a …​                 | I want to …​                                                    | So that I can…​                                                                    |
+|----------|-------------------------|-----------------------------------------------------------------|------------------------------------------------------------------------------------|
+| `* * *`  | new user                | see usage instructions                                          | refer to instructions when I forget how to use the App                             |
+| `* * *`  | user                    | add a new contact                                               | easily connect with them                                                           |
+| `* * *`  | user                    | delete a contact                                                | remove entries that I no longer need                                               |
+| `* * *`  | user                    | find a person by name                                           | locate details of persons without having to go through the entire list             |
+| `* *`    | user                    | update my contacts information                                  | always keep an updated version of contact information                              |
+| `* *`    | user                    | undo my last action                                             | prevent the accidental deletion of all my contacts                                 |
+| `* *`    | user                    | redo my latest undone action                                    | prevent the accidental undoing of certain actions                                  |    
+| `*`      | user with many contacts | search contacts by name                                         | locate a contact easily                                                            |
+| `*`      | user                    | add a tag information to contacts                               | easily locate and connect with individuals such as classmates or club members      |
+| `*`      | student                 | filter contacts by tags such as "group project" or "internship" | easily access related contacts                                                     |
+| `*`      | user with many tags     | categorize tags into different groups                           | easily organize contacts and locate individuals such as classmates or club members |
 
 ### Use cases
 
@@ -398,13 +398,13 @@ Priorities: High (must have) - `* * *`, Medium (nice to have) - `* *`, Low (unli
 
       Use case ends.
 
-**Use case: UC04 - Add tags to a contact**\
+**Use case: UC04 - Add tags to a contact**
 **Precondition**: Contact to add tags to already exists
 
 **MSS**
 1. User requests to add tags to a contact.
 2. CampusConnect searches the contact list and finds the correct contact.
-3. CampusConnect add tags to the contact.
+3. CampusConnect adds tags to the contact.
 4. CampusConnect displays success message.
 
    Use case ends.
@@ -419,65 +419,81 @@ Priorities: High (must have) - `* * *`, Medium (nice to have) - `* *`, Low (unli
       Use case ends.
 
 
-* 1b. Tag already exists for the contact
-    * 1b1. CampusConnect shows error message.
-    * 1b2. User enters input again
-
-      Steps 1b1-1b2 repeat until non-duplicate tags are input
+* 3a. Tag already exists for the contact
+    * 3a1. CampusConnect shows error message.
 
       Use case ends.
 
-
-**Use case: UC05 - Sort contacts by criterion**
+**Use cases: UC05 - Delete a tag from a contact**
+**Precondition**: Contact to delete a tag from already exists
 
 **MSS**
-1. User requests to sort list by criterion.
-2. CampusConnect sorts the list.
-3. CampusConnect displays the sorted list.
+1. User requests to delete a specific tag from a contact
+2. CampusConnect searches the contact list and finds the correct contact.
+3. CampusConnect deletes the specific tag from the contact
+4. CampusConnect displays success message
 
-   Use case ends.
+   Use case ends
 
 **Extensions**
-* 1a. Contact list is empty
+* 1a. Input format is invalid
+    * 1a1. CampusConnect shows error message.
+    * 1a2 User enters input again.
 
-  Use case ends.
+      Steps 1a1-1a2 repeat until input format is valid.
 
+      Use case ends.
 
-* 1b. Input format is invalid.
-    * 1b1. CampusConnect shows error message.
-    * 1b2. User enters input again.
+* 3a. The contact does not contain the tag user wants to delete
+    * 3a1. CampusConnect shows error message.
+
+      Use case ends.
 
-      Steps 1b1-1b2 repeat until input format is valid.
+**Use cases: UC06 - Undo an execution of command**
+**Precondition**: At least one valid command has been executed by the user.
 
-      Use case ends.
+**MSS**
+1. User requests to undo the most recent command execution.
+2. CampusConnect reverts the most recent command, restoring the data to its previous state 
+before the command was executed.
 
+   Use case ends
 
-* 1c. Invalid criterion input.
-    * 1c1. CampusConnect shows error message.
-    * 1c2. User enters input again.
+**Extensions**
+* 1a. Input format is invalid.
+    * 1a1. CampusConnect shows error message.
+    * 1a2. User enters input again.
 
-      Steps 1c1-1c2 repeat until input format is valid.
+      Steps 1a1-1a2 repeat until input format is valid.
 
       Use case ends.
 
+* 1b. No earlier data to revert.
+    * 1b1. CampusConnect shows error message.
 
-**Use case: UC06 - Pin contacts to the top of the list**\
-**Precondition**: Contact list is not empty
+      Use cases ends.
 
-**MSS**
-1. User requests to pin contact to the top of the list.
-2. CampusConnect marks contact as pinned.
-3. CampusConnect displays success message.
+**Use Case: UC07 - Redo Command Execution**
+
+**Precondition: The user has previously undone at least one command.**
+
+**MSS:**
+1. The user requests to redo the most recently undone command.
+2. CampusConnect restores the data to the state it was in immediately before the undo.
 
    Use case ends.
 
-**Extensions**
+**Extensions:**
+* 1a. Invalid Input Format:
+    * 1a1. CampusConnect displays an error message indicating the input format is invalid.
+    * 1a2. The user re-enters the input.
 
-* 1a. Input format is invalid.
-    * 1a1. CampusConnect shows error message.
-    * 1a2. User enters input again.
+      Steps 1a1-1a2 repeat until the input format is valid.
 
-      Steps 1a1-1a2 repeat until input format is valid.
+      Use case ends.
+
+* 1b. No More Commands to Redo:
+    * 1b1. CampusConnect displays an error message indicating that there are no more commands to redo.
 
       Use case ends.
 

docs/diagrams/CommitActivityDiagram.puml

@@ -3,16 +3,23 @@ skin rose
 skinparam ActivityFontSize 15
 skinparam ArrowFontSize 12
 start
-:User executes command;
+:User inputs and
+executes command;
 
 'Since the beta syntax does not support placing the condition outside the
 'diamond we place it as the true branch instead.
-
-if () then ([command commits CampusConnect])
-    :Purge redundant states;
-    :Save CampusConnect to
-    campusConnectStateList;
+: Parse command;
+if () then ([command will modify CampusConnect])
+    :Purge undone states;
+    :Save current CampusConnect;
+    :Excutes Command;
+    if () then ([command execution fails])
+    : Recover to old version of
+    CampusConnect;
+    else ([else])
+    endif
 else ([else])
+:Excutes Command;
 endif
 stop
 @enduml

docs/diagrams/UndoSequenceDiagram-Model.puml

@@ -4,19 +4,37 @@ skinparam ArrowFontStyle plain
 
 box Model MODEL_COLOR_T1
 participant ":Model" as Model MODEL_COLOR
+participant ":CampusConnect" as CampusConnect MODEL_COLOR
 participant ":VersionedCampusConnect" as VersionedCampusConnect MODEL_COLOR
 end box
 
 [-> Model : undoCampusConnect()
 activate Model
 
-Model -> VersionedCampusConnect : undo()
+Model -> CampusConnect: recoverPreviousState()
+activate CampusConnect
+
+CampusConnect -> VersionedCampusConnect: extractOldData()
+activate VersionedCampusConnect
+
+VersionedCampusConnect -> VersionedCampusConnect: saveCurrentData()
 activate VersionedCampusConnect
 
-VersionedCampusConnect -> VersionedCampusConnect :resetData(ReadOnlyCampusConnect)
-VersionedCampusConnect --> Model :
+VersionedCampusConnect --> VersionedCampusConnect
+deactivate VersionedCampusConnect
+
+VersionedCampusConnect --> CampusConnect:
 deactivate VersionedCampusConnect
 
+CampusConnect --> Model: cc
+deactivate CampusConnect
+
+Model -> Model: setCampusConnect(cc)
+activate Model
+
+Model --> Model
+deactivate Model
+
 [<-- Model
 deactivate Model
 

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

@@ -62,7 +62,7 @@ public CommandResult execute(String commandText) throws CommandException, ParseE
             storage.saveCampusConnect(model.getCampusConnect());
         } catch (CommandException e) {
             if (!(command instanceof RedoCommand)) {
-                model.undoCampusConnect();
+                model.undoExceptionalCommand();
             }
             throw e;
         } catch (AccessDeniedException e) {

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

@@ -77,6 +77,10 @@ public ReadOnlyCampusConnect recoverUndoneState() throws RedoException {
         return out;
     }
 
+    public ReadOnlyCampusConnect recoverStateWithoutSaving() throws UndoException {
+        return versionedCampusConnect.extractOldData();
+    }
+
     /**
      * Replaces the contents of the person list with {@code persons}.
      * {@code persons} must not contain duplicate persons.

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

@@ -131,17 +131,22 @@ public interface Model {
     void updateFilteredPersonList(Predicate<Person> predicate);
 
     /**
-     * Undo the previous actions of users
+     * Undoes the previous actions of users
      */
     void undoCampusConnect() throws CommandException;
 
     /**
-     * Restore state before previous undo actions of users
+     * Restores state before previous undo actions of users
      */
     void redoCampusConnect() throws CommandException;
 
     /**
-     * Save current state of model before execution.
+     * Saves current state of model before execution.
      */
     void saveCurrentCampusConnect();
+
+    /**
+     * Undoes a state without saving current state when execution fails.
+     */
+    void undoExceptionalCommand() throws CommandException;
 }

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

@@ -231,5 +231,11 @@ public void redoCampusConnect() throws CommandException {
     public void saveCurrentCampusConnect() {
         campusConnect.saveCurrentState();
     }
+
+    @Override
+    public void undoExceptionalCommand() throws CommandException {
+        ReadOnlyCampusConnect cc = campusConnect.recoverStateWithoutSaving();
+        this.setCampusConnect(cc);
+    }
 }
 

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

@@ -214,6 +214,11 @@ public void setTagsCategory(Tag t, TagCategory cat) {
         public TagCategory getTagCategory(Tag t) {
             throw new AssertionError("This method should not be called");
         }
+
+        @Override
+        public void undoExceptionalCommand() {
+            throw new AssertionError("This method should not be called");
+        }
     }
 
     /**