By: Team SE-EDU
Since: Jun 2016
Licence: MIT
Refer to the guide here.
The Architecture Diagram given above explains the high-level design of the App. Given below is a quick overview of each component.
💡
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The .puml files used to create diagrams in this document can be found in the diagrams folder.
Refer to the Using PlantUML guide to learn how to create and edit diagrams.
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At app launch: Initializes the components in the correct sequence, and connects them up with each other.
-
At shut down: Shuts down the components and invokes cleanup method where necessary.
Commons
represents a collection of classes used by multiple other components.
The following class plays an important role at the architecture level:
-
LogsCenter
: Used by many classes to write log messages to the App’s log file.
The rest of the App consists of four components.
Each of the four components
-
Defines its API in an
interface
with the same name as the Component. -
Exposes its functionality using a
{Component Name}Manager
class.
For example, the Logic
component (see the class diagram given below) defines it’s API in the Logic.java
interface and exposes its functionality using the LogicManager.java
class.
The Sequence Diagram below shows how the components interact with each other for the scenario where the user issues the command delete 1
.
The sections below give more details of each component.
API : Ui.java
The UI consists of a MainWindow
that is made up of parts e.g.CommandBox
, ResultDisplay
, PersonListPanel
, StatusBarFooter
etc. All these, including the MainWindow
, inherit from the abstract UiPart
class.
The UI
component uses JavaFx UI framework. The layout of these UI parts are defined in matching .fxml
files that are in the src/main/resources/view
folder. For example, the layout of the MainWindow
is specified in MainWindow.fxml
The UI
component,
-
Executes user commands using the
Logic
component. -
Listens for changes to
Model
data so that the UI can be updated with the modified data.
API :
Logic.java
-
Logic
uses theAddressBookParser
class to parse the user command. -
This results in a
Command
object which is executed by theLogicManager
. -
The command execution can affect the
Model
(e.g. adding a person). -
The result of the command execution is encapsulated as a
CommandResult
object which is passed back to theUi
. -
In addition, the
CommandResult
object can also instruct theUi
to perform certain actions, such as displaying help to the user.
Given below is the Sequence Diagram for interactions within the Logic
component for the execute("delete 1")
API call.
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The lifeline for DeleteCommandParser should end at the destroy marker (X) but due to a limitation of PlantUML, the lifeline reaches the end of diagram.
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API : Model.java
The Model
,
-
stores a
UserPref
object that represents the user’s preferences. -
stores the Address Book data.
-
exposes 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. -
does not depend on any of the other three components.
API : Storage.java
The Storage
component,
-
can save
UserPref
objects in json format and read it back. -
can save the Address Book data in json format and read it back.
This section describes some noteworthy details on how certain features are implemented.
The undo/redo mechanism is facilitated by VersionedAddressBook
.
It extends AddressBook
with an undo/redo history, stored internally as an addressBookStateList
and currentStatePointer
.
Additionally, it implements the following operations:
-
VersionedAddressBook#commit()
— Saves the current address book state in its history. -
VersionedAddressBook#undo()
— Restores the previous address book state from its history. -
VersionedAddressBook#redo()
— Restores a previously undone address book state from its history.
These operations are exposed in the Model
interface as Model#commitAddressBook()
, Model#undoAddressBook()
and Model#redoAddressBook()
respectively.
Given below is an example usage scenario and how the undo/redo mechanism behaves at each step.
Step 1. The user launches the application for the first time. The VersionedAddressBook
will be initialized with the initial address book state, and the currentStatePointer
pointing to that single address book state.
Step 2. The user executes delete 5
command to delete the 5th person in the address book. The delete
command calls Model#commitAddressBook()
, causing the modified state of the address book after the delete 5
command executes to be saved in the addressBookStateList
, and the currentStatePointer
is shifted to the newly inserted address book state.
Step 3. The user executes add n/David …
to add a new person. The add
command also calls Model#commitAddressBook()
, causing another modified address book state to be saved into the addressBookStateList
.
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If a command fails its execution, it will not call Model#commitAddressBook() , so the address book state will not be saved into the addressBookStateList .
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Step 4. The user now decides that adding the person was a mistake, and decides to undo that action by executing the undo
command. The undo
command will call Model#undoAddressBook()
, which will shift the currentStatePointer
once to the left, pointing it to the previous address book state, and restores the address book to that state.
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If the currentStatePointer is at index 0, pointing to the initial address book state, then there are no previous address book states to restore. The undo command uses Model#canUndoAddressBook() to check if this is the case. If so, it will return an error to the user rather than attempting to perform the undo.
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The following sequence diagram shows how the undo operation works:
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The lifeline for UndoCommand should end at the destroy marker (X) but due to a limitation of PlantUML, the lifeline reaches the end of diagram.
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The redo
command does the opposite — it calls Model#redoAddressBook()
, which shifts the currentStatePointer
once to the right, pointing to the previously undone state, and restores the address book to that state.
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If the currentStatePointer is at index addressBookStateList.size() - 1 , pointing to the latest address book state, then there are no undone address book states to restore. The redo command uses Model#canRedoAddressBook() to check if this is the case. If so, it will return an error to the user rather than attempting to perform the redo.
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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#commitAddressBook()
, Model#undoAddressBook()
or Model#redoAddressBook()
. Thus, the addressBookStateList
remains unchanged.
Step 6. The user executes clear
, which calls Model#commitAddressBook()
. Since the currentStatePointer
is not pointing at the end of the addressBookStateList
, all address book states after the currentStatePointer
will be purged. We designed it this way because it no longer makes sense to redo the add n/David …
command. This is the behavior that most modern desktop applications follow.
The following activity diagram summarizes what happens when a user executes a new command:
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Alternative 1 (current choice): Saves the entire address book.
-
Pros: Easy to implement.
-
Cons: May have performance issues in terms of memory usage.
-
-
Alternative 2: Individual command knows how to undo/redo by itself.
-
Pros: Will use less memory (e.g. for
delete
, just save the person being deleted). -
Cons: We must ensure that the implementation of each individual command are correct.
-
-
Alternative 1 (current choice): Use a list to store the history of address book states.
-
Pros: Easy for new Computer Science student undergraduates to understand, who are likely to be the new incoming developers of our project.
-
Cons: Logic is duplicated twice. For example, when a new command is executed, we must remember to update both
HistoryManager
andVersionedAddressBook
.
-
-
Alternative 2: Use
HistoryManager
for undo/redo-
Pros: We do not need to maintain a separate list, and just reuse what is already in the codebase.
-
Cons: Requires dealing with commands that have already been undone: We must remember to skip these commands. Violates Single Responsibility Principle and Separation of Concerns as
HistoryManager
now needs to do two different things.
-
We are using java.util.logging
package for logging. The LogsCenter
class is used to manage the logging levels and logging destinations.
-
The logging level can be controlled using the
logLevel
setting in the configuration file (See Section 3.4, “Configuration”) -
The
Logger
for a class can be obtained usingLogsCenter.getLogger(Class)
which will log messages according to the specified logging level -
Currently log messages are output through:
Console
and to a.log
file.
Logging Levels
-
SEVERE
: Critical problem detected which may possibly cause the termination of the application -
WARNING
: Can continue, but with caution -
INFO
: Information showing the noteworthy actions by the App -
FINE
: Details that is not usually noteworthy but may be useful in debugging e.g. print the actual list instead of just its size
Refer to the guide here.
Refer to the guide here.
Refer to the guide here.
Target user profile:
-
has a need to manage a significant number of contacts
-
prefer desktop apps over other types
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can type fast
-
prefers typing over mouse input
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is reasonably comfortable using CLI apps
Value proposition: manage contacts faster than a typical mouse/GUI driven app
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 person |
|
|
user |
delete a person |
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 |
hide private contact details by default |
minimize chance of someone else seeing them by accident |
|
user with many persons in the address book |
sort persons by name |
locate a person easily |
{More to be added}
(For all use cases below, the System is the Xpire
and the Actor is the user
, unless specified otherwise)
MSS
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User requests to list items
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Xpire shows a list of items
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User requests to delete a specific item in the list
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Xpire deletes the item
Use case ends.
Extensions
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2a. The list is empty.
Use case ends.
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3a. The given index is invalid.
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3a1. Expire shows an error message.
Use case resumes at step 2.
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{More to be added}
Accessibility
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The app shall be accessible by people who have downloaded the JAR file.
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The app shall be accessible to people who are colour blind, to the extent that they shall be able to discern all text and other information displayed by the system as easily as a person without colour blindness.
Availability
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The app shall be available once it is started up and running.
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Reminders shall only be available on the app.
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Reminders shall only be available after the app is started.
Efficiency
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The app should start up within 5 seconds.
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The response to any user action should become visible within 5 seconds.
Performance
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The app list should be able to hold up to 1000 items without a noticeable sluggishness in performance for typical usage.
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The app should be able to sort up to 1000 items without any sags in performance.
Reliability
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The app shall only accept and process user actions written in the correct format.
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The app shall throw appropriate exceptions when any user action is in an invalid format.
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The app shall throw appropriate exceptions when any user action fails to be processed.
Integrity
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The precision of calculations with derived data shall be at the same degree of precision as the originating source data.
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All dates entered will be parsed accurately as to the original date format.
Product Scope
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The product is not required to handle items without expiry dates.
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The product is not required to handle items without names.
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The product is not required to produce reminders when the app is inactive.
Usability
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A user with above average typing speed for regular English text (i.e. not code, not system admin commands) should be able to accomplish most of the tasks faster using commands than using the mouse.
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The user interface should be self-explanatory and intuitive enough for first-time users or users who are not IT-savvy.
Maintainability
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A development programmer who has at least one year of experience supporting this software application shall be able to add a new product feature, including source code modifications and testing, with no more than two days of labour.
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The app code base shall be easy to read and interpret by a developer with at least one year of experience.
Modifiability
-
Function calls shall not be nested more than two levels deep.
Installability
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The installation process shall be convenient. The application shall be downloaded as a JAR file from the newest tagged release.
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The software shall be installed from Github, a popular portable medium.
Interoperability
. Should work on any mainstream OS as long as it has Java 11
or above installed.
{More to be added}
Given below are instructions to test the app manually.
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These instructions only provide a starting point for testers to work on; testers are expected to do more exploratory testing. |
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Initial launch
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Download the jar file and copy into an empty folder
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Double-click the jar file
Expected: Shows the GUI with a set of sample contacts. The window size may not be optimum.
-
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Saving window preferences
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Resize the window to an optimum size. Move the window to a different location. Close the window.
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Re-launch the app by double-clicking the jar file.
Expected: The most recent window size and location is retained.
-
{ more test cases … }
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Deleting an item while all items are listed
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Prerequisites: List all items using the
list
command. Multiple items in the list. -
Test case:
delete 1
Expected: First item is deleted from the list. Details of the deleted item shown in the status message. Timestamp in the status bar is updated. -
Test case:
delete 0
Expected: No item is deleted. Error details shown in the status message. Status bar remains the same. -
Other incorrect delete commands to try:
delete
,delete x
(where x is larger than the list size) {give more}
Expected: Similar to previous.
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{ more test cases … }