TABCC (The Address Book for Content Creators) - Developer Guide

By: Team T15-B1 Since: Sep 2017 Licence: MIT

1. Setting up
2. Design
3. Implementation
4. Documentation
5. Testing
6. Dev Ops
Appendix A: Suggested Programming Tasks to Get Started
- A.1. Improving each component
- A.2. Creating a new command: remark
Appendix B: User Stories
Appendix C: Use Cases
Appendix D: Non Functional Requirements
Appendix E: Glossary

1. Setting up

1.1. Prerequisites

JDK 1.8.0_60 or later

ℹ️
Having any Java 8 version is not enough.
This app will not work with earlier versions of Java 8.
IntelliJ IDE

ℹ️
IntelliJ by default has Gradle and JavaFx plugins installed.
Do not disable them. If you have disabled them, go to File > Settings > Plugins to re-enable them.

1.2. Setting up the project in your computer

Fork this repo, and clone the fork to your computer
Open IntelliJ (if you are not in the welcome screen, click File > Close Project to close the existing project dialog first)
Set up the correct JDK version for Gradle
1. Click Configure > Project Defaults > Project Structure
2. Click New… and find the directory of the JDK
Click Import Project
Locate the build.gradle file and select it. Click OK
Click Open as Project
Click OK to accept the default settings
Open a console and run the command gradlew processResources (Mac/Linux: ./gradlew processResources). It should finish with the BUILD SUCCESSFUL message.
This will generate all resources required by the application and tests.

1.3. Verifying the setup

Run the seedu.address.MainApp and try a few commands
Run the tests to ensure they all pass.

1.4. Configurations to do before writing code

1.4.1. Configuring the coding style

This project follows oss-generic coding standards. IntelliJ’s default style is mostly compliant with ours but it uses a different import order from ours. To rectify,

Go to File > Settings… (Windows/Linux), or IntelliJ IDEA > Preferences… (macOS)
Select Editor > Code Style > Java
Click on the Imports tab to set the order
- For Class count to use import with '*' and Names count to use static import with '*': Set to 999 to prevent IntelliJ from contracting the import statements
- For Import Layout: The order is import static all other imports, import java.*, import javax.*, import org.*, import com.*, import all other imports. Add a <blank line> between each import

Optionally, you can follow the UsingCheckstyle.adoc document to configure Intellij to check style-compliance as you write code.

1.4.2. Updating documentation to match your fork

After forking the repo, links in the documentation will still point to the se-edu/addressbook-level4 repo. If you plan to develop this as a separate product (i.e. instead of contributing to the se-edu/addressbook-level4) , you should replace the URL in the variable repoURL in DeveloperGuide.adoc and UserGuide.adoc with the URL of your fork.

1.4.3. Setting up CI

Set up Travis to perform Continuous Integration (CI) for your fork. See UsingTravis.adoc to learn how to set it up.

Optionally, you can set up AppVeyor as a second CI (see UsingAppVeyor.adoc).

ℹ️	Having both Travis and AppVeyor ensures your App works on both Unix-based platforms and Windows-based platforms (Travis is Unix-based and AppVeyor is Windows-based)

1.4.4. Getting started with coding

When you are ready to start coding,

Get some sense of the overall design by reading the Architecture section.
Take a look at the section Suggested Programming Tasks to Get Started.

2. Design

2.1. Architecture

Figure 2.1.1 : Architecture Diagram

The Architecture Diagram given above explains the high-level design of the App. Given below is a quick overview of each component.

💡	The `.pptx` files used to create diagrams in this document can be found in the diagrams folder. To update a diagram, modify the diagram in the pptx file, select the objects of the diagram, and choose `Save as picture`.

Main has only one class called MainApp. It is responsible for,

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. Two of those classes play important roles at the architecture level.

EventsCenter : This class (written using Google’s Event Bus library) is used by components to communicate with other components using events (i.e. a form of Event Driven design)
LogsCenter : Used by many classes to write log messages to the App’s log file.

The rest of the App consists of four components.

UI : The UI of the App.
Logic : The command executor.
Model : Holds the data of the App in-memory.
Storage : Reads data from, and writes data to, the hard disk.

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.

Figure 2.1.2 : Class Diagram of the Logic Component

Events-Driven nature of the design

The Sequence Diagram below shows how the components interact for the scenario where the user issues the command delete 1.

Figure 2.1.3a : Component interactions for delete 1 command (part 1)

ℹ️	Note how the `Model` simply raises a `AddressBookChangedEvent` when the Address Book data are changed, instead of asking the `Storage` to save the updates to the hard disk.

The diagram below shows how the EventsCenter reacts to that event, which eventually results in the updates being saved to the hard disk and the status bar of the UI being updated to reflect the 'Last Updated' time.

Figure 2.1.3b : Component interactions for delete 1 command (part 2)

ℹ️	Note how the event is propagated through the `EventsCenter` to the `Storage` and `UI` without `Model` having to be coupled to either of them. This is an example of how this Event Driven approach helps us reduce direct coupling between components.

The sections below give more details of each component.

2.2. UI component

Figure 2.2.1 : Structure of the UI Component

API : Ui.java

The UI consists of a LockScreen which contains MainWindow that is made up of parts e.g.CommandBox, ResultDisplay, PersonListPanel, StatusBarFooter, BrowserPanel 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.
Binds itself to some data in the Model so that the UI can auto-update when data in the Model change.
Responds to events raised from various parts of the App and updates the UI accordingly.

2.3. Logic component

Figure 2.3.1 : Structure of the Logic Component

Figure 2.3.2 : Structure of Commands in the Logic Component. This diagram shows finer details concerning XYZCommand and Command in Figure 2.3.1

API : Logic.java

Logic uses the AddressBookParser class to parse the user command.
This results in a Command object which is executed by the LogicManager.
The command execution can affect the Model (e.g. adding a person) and/or raise events.
The result of the command execution is encapsulated as a CommandResult object which is passed back to the Ui.

Given below is the Sequence Diagram for interactions within the Logic component for the execute("delete 1") API call.

Figure 2.3.1 : Interactions Inside the Logic Component for the delete 1 Command

2.4. Model component

Figure 2.4.1 : Structure of the Model Component

API : Model.java

The Model,

stores a UserPref object that represents the user’s preferences.
stores the Address Book data.
exposes an unmodifiable ObservableList<ReadOnlyPerson> 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.

2.5. Storage component

Figure 2.5.1 : Structure of the Storage Component

API : Storage.java

The Storage component,

can save UserPref objects in json format and read it back.
can save the Address Book data in xml format and read it back.

2.6. Common classes

Classes used by multiple components are in the seedu.addressbook.commons package.

3. Implementation

This section describes some noteworthy details on how certain features are implemented.

3.1. Lock Screen

The Lock Screen loads first before the Main Window. The status and logic of unlocking the application resides inside LogicManager.

LogicManager contains boolean variable isLock to keep track of the application’s lock status. Assuming that there is a password set in the preference file, on launch isLock will be set to true, and the LockScreen will be loaded onto the Stage.

ℹ️	If there is not password set in the preference file `isLock` will be set to false and the `LockScreen` will not be loaded onto the `Stage`.

Upon entering a password, the entered password will be checked using the isPassword method which resides in LogicManager. isPassword method then calls the checkPassword method inside UserPrefs as UserPrefs reads the password from the preference file. The entered password is converted to a MD5 hash string using convertToMD5 method inside UserPrefs before comparing the passwords. Similarly, a password will be converted to MD5 hash string before storing in the preference file.

In order to change the password, a new command changepwd is implemented.

changepwd NEW_PASSWORD OLD_PASSWORD

ℹ️	Suppose that the user uses the application for the first time, there will be no password set in the preference file. Using the same `changepwd` command the user can set the password by leaving the [old_password] field empty.

Upon successful unlocking of the application, the lock screen will call loadMainWindow() which creates a new MainWindow and loads it into the Stage, replacing the existing LockScreen.

3.1.1. Design Considerations

Aspect: Implementation of LockScreen
Alternative 1 (current choice): Create a LockScreen class to display the lock screen.
Pros: Easy to create a custom lock screen window with its own elements. Height, width and elements inside the lock screen window (e.g. password field) can be set isolated from the MainWindow.
Cons: Hard for new developers to understand the template pattern.

Alternative 2: Create a lock screen stackpane inside the MainWndow class.
Pros: Do not need to create a entire class.
Cons: Elements in the main window have to be hardcoded to appear or disappear when necessary. For example, the password field have to be removed after login and the other main window elements (e.g. CommandBox) have to appear.
There will also be restrictions to the arrangement of the elements as the FXML placeholder have to be initialised despite not being used. For example, the CommandBoxPlaceholder have to be initialised in the lock screen despite not being used.

3.2. FindEmailCommand

This enhancement is aiming to make the searches more powerful.
To find a person on the AddressBook, user is no longer restricted to just name search. User can now search for a person using Email.
To use this command, user just need to type in “findemail” follow by a white space, and typing in the email of the person the user is trying to find.

The implementation of the find email command consist of 3 new classes, namely FindEmailCommand.java, EmailContainsKeywordsPredicate.java and FindEmailCommandParser.java. FindEmailCommand.java and FindEmailCommandParser.java resides in the logic component, while EmailsContainKeywordsPredicate.java resides in the model component.

Figure 3.1.1

Functions of classes in FindEmailCommand

1) FindEmailCommand.java: This class searches and lists the persons in address book whose email contains any of the argument keyword. This class extends the abstract class Command.

2) EmailContainsKeyWordsPredicate.java: This class tests that a person’s email matches any of the keyword given. This class implements Predicate<ReadOnlyPerson> interface.

3) FindEmailCommandParser.java: This class parses input arguments and creates a new FindEmailCommand object.

Implementations of Find Email Command
The FindEmailCommand are implemented this way:

public class FindEmailCommand extends Command{
    @Override
    public CommandResult execute() {
	//command logic
    }
}

The EmailContainsKeywordsPredicate.java class is implemented this way:

public class EmailContainsKeywordsPredicate implements Predicate<ReadOnlyPerson> {
    @Override
    public boolean test(ReadOnlyPerson person) {
        //test logic
    }

Lastly, the FindEmailCommandParser.java is implemented this way:

public class FindEmailCommandParser {

    public FindEmailCommand parse(String args) throws ParseException {
        //parser logic
    }
}

3.3. FavCommand

This enhancement allows users to add or remove people to and fro a favourites list.
To use this command, users just need to type in fave <index of targeted person> <true/false>.
true will add the targeted person to the favourites, while false removes the person.
The favourites state is a boolean variable saved in the addressbook.xml file.
The implementation of the fave command consists of 2 new classes, namely FavCommand.java, FavCommandParser.java.
Both these classes reside in the Logic component.

Figure 3.3.1

Functions of classes in FavCommand

1) FavCommand.java: This class sets the favourite boolean variable in a target Person as either true or false. This class extends the abstract class UndoableCommand.

2) FavCommandParser.java: This class parses input arguments and creates a new FavCommand object.

Implementations of FavCommand
The FavCommand is implemented this way:

public class FavCommand extends Command{
    @Override
    public CommandResult executeUndoableCommand() {
	//command logic
    }
}

The FavCommandParser.java is implemented this way:

public class FavCommandParser {

    public FindEmailCommand parse(String args) throws ParseException {
        //parser logic
    }
}

3.4. FindFavCommand

This enhancement allows users to view the favourites list.
To use this command, users just need to type in findfav or ffav.
The implementation of the fave command consists of 3 new classes, namely FindFavCommand.java, FindFavCommandParser.java and FavouritePredicate.java.
The first two class reside in the Logic component, and the latter class resides in the Model component.

Functions of classes in FindFavCommand

1) FavCommand.java: This class searches and lists the persons in address book who are marked as favourites. This class extends the abstract class Command.

2) FavouritePredicate.java: This class tests that a person is marked as a favourite. This class implements Predicate<ReadOnlyPerson> interface.

3) FindEmailCommandParser.java: This class parses input arguments and creates a new FindFavCommand object.

Implementations of FindFavCommand

The FindFavCommand is implemented this way:

public class FindFavCommand extends Command{
    @Override
    public CommandResult execute() {
	//command logic
    }
}

The FindFavCommandParser.java is implemented this way:

public class FindFavCommandParser {

    public FindEmailCommand parse(String args) throws ParseException {
        //parser logic
    }
}

The FavouritePredicate.java is implemented this way:

public class FavouritePredicate extends Predicate<ReadOnlyPerson> {

    @Override
    public boolean test(ReadOnlyPerson) {
        //predicate logic
    }
}

3.5. Undo/Redo mechanism

The undo/redo mechanism is facilitated by an UndoRedoStack, which resides inside LogicManager. It supports undoing and redoing of commands that modifies the state of the address book (e.g. add, edit). Such commands will inherit from UndoableCommand.

UndoRedoStack only deals with UndoableCommands. Commands that cannot be undone will inherit from Command instead. The following diagram shows the inheritance diagram for commands:

As you can see from the diagram, UndoableCommand adds an extra layer between the abstract Command class and concrete commands that can be undone, such as the DeleteCommand. Note that extra tasks need to be done when executing a command in an undoable way, such as saving the state of the address book before execution. UndoableCommand contains the high-level algorithm for those extra tasks while the child classes implements the details of how to execute the specific command. Note that this technique of putting the high-level algorithm in the parent class and lower-level steps of the algorithm in child classes is also known as the template pattern.

Commands that are not undoable are implemented this way:

public class ListCommand extends Command {
    @Override
    public CommandResult execute() {
        // ... list logic ...
    }
}

With the extra layer, the commands that are undoable are implemented this way:

public abstract class UndoableCommand extends Command {
    @Override
    public CommandResult execute() {
        // ... undo logic ...

        executeUndoableCommand();
    }
}

public class DeleteCommand extends UndoableCommand {
    @Override
    public CommandResult executeUndoableCommand() {
        // ... delete logic ...
    }
}

Suppose that the user has just launched the application. The UndoRedoStack will be empty at the beginning.

The user executes a new UndoableCommand, delete 5, to delete the 5th person in the address book. The current state of the address book is saved before the delete 5 command executes. The delete 5 command will then be pushed onto the undoStack (the current state is saved together with the command).

As the user continues to use the program, more commands are added into the undoStack. For example, the user may execute add n/David … to add a new person.

ℹ️	If a command fails its execution, it will not be pushed to the `UndoRedoStack` at all.

The user now decides that adding the person was a mistake, and decides to undo that action using undo.

We will pop the most recent command out of the undoStack and push it back to the redoStack. We will restore the address book to the state before the add command executed.

ℹ️	If the `undoStack` is empty, then there are no other commands left to be undone, and an `Exception` will be thrown when popping the `undoStack`.

The following sequence diagram shows how the undo operation works:

The redo does the exact opposite (pops from redoStack, push to undoStack, and restores the address book to the state after the command is executed).

ℹ️	If the `redoStack` is empty, then there are no other commands left to be redone, and an `Exception` will be thrown when popping the `redoStack`.

The user now decides to execute a new command, clear. As before, clear will be pushed into the undoStack. This time the redoStack is no longer empty. It will be purged as it no longer make sense to redo the add n/David command (this is the behavior that most modern desktop applications follow).

Commands that are not undoable are not added into the undoStack. For example, list, which inherits from Command rather than UndoableCommand, will not be added after execution:

The following activity diagram summarize what happens inside the UndoRedoStack when a user executes a new command:

3.5.1. Design Considerations

Aspect: Implementation of UndoableCommand
Alternative 1 (current choice): Add a new abstract method executeUndoableCommand()
Pros: We will not lose any undone/redone functionality as it is now part of the default behaviour. Classes that deal with Command do not have to know that executeUndoableCommand() exist.
Cons: Hard for new developers to understand the template pattern.
Alternative 2: Just override execute()
Pros: Does not involve the template pattern, easier for new developers to understand.
Cons: Classes that inherit from UndoableCommand must remember to call super.execute(), or lose the ability to undo/redo.

Aspect: How undo & redo executes
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.

Aspect: Type of commands that can be undone/redone
Alternative 1 (current choice): Only include commands that modifies the address book (add, clear, edit).
Pros: We only revert changes that are hard to change back (the view can easily be re-modified as no data are lost).
Cons: User might think that undo also applies when the list is modified (undoing filtering for example), only to realize that it does not do that, after executing undo.
Alternative 2: Include all commands.
Pros: Might be more intuitive for the user.
Cons: User have no way of skipping such commands if he or she just want to reset the state of the address book and not the view.
Additional Info: See our discussion here.

Aspect: Data structure to support the undo/redo commands
Alternative 1 (current choice): Use separate stack for undo and redo
Pros: Easy to understand 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 and UndoRedoStack.
Alternative 2: Use HistoryManager for undo/redo
Pros: We do not need to maintain a separate stack, 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.

3.6. Select command

The select command opens up the selected contact’s profile GUI, which is implemented in the ProfilePanel.java class. This command makes use of the YouTube Data API to retrieve information from the YouTube servers.

The method handlePersonPanelSelectionChangedEvent() listens for the event triggered by the select command and passes the person object of the selected contact to the loadPersonProfile() method.

@Subscribe
private void handlePersonPanelSelectionChangedEvent(PersonPanelSelectionChangedEvent event) throws IOException {
    logger.info(LogsCenter.getEventHandlingLogMessage(event));
    loadPersonPage(event.getNewSelection().person);
}

With the person object, YouTubeAuthorizer.getYouTubeChannel() is called with the channel ID of the person and the needed channel resources as arguments.

String personChannelId = person.getChannelId().toString();

assert personChannelId != null : "personChannelId should not be null";
channel = YouTubeAuthorizer.getYouTubeChannel(person.getChannelId().toString(), "statistics,snippet");

3.6.1. Dynamic information:

Dynamic information is information retrieved from the YouTube servers every time the user views the profile of the contact. In the list below, the channel resource associated with the category of dynamic information is put in brackets.

Categories included in current version:

Channel title (snippet)
Channel thumbnail (snippet)
Channel description (snippet)
Subscriber count (statistics)
Total view count (statistics)
Video count (statistics)

Some of the dynamic information, such as view count, grabbed from the YouTube Servers are difficult to read due to the long chain of digits that each category might be presented in (eg. 191929603).

To tackle this problem, the formatNumber() method is implemented to reduce the number of digits with the order of magnitude suffix placed behind the simplified number. The result from formatting the number '191929603' can be seen in the views categories in Figure 3.5.2.1 below.

Currently the formatNumber() method supports up to the billion suffix. Suffix representing larger order of magnitudes will be added when the need arises.

private String formatNumber(long number) {
    final long thousand = 1000L;
    final long million = 1000000L;
    final long billion = 1000000000L;

    if (number >= billion) {
        return String.format("%.1f%c", (double) number / billion, 'b');
    } else if (number >= million) {
        return String.format("%.1f%c", (double) number / million, 'm');
    } else if (number >= thousand) {
        return String.format("%.1f%c", (double) number / thousand, 'k');
    } else {
        return number + "";
    }
}

3.6.2. Profile GUI

Displayed in the profile are the dynamic information about the channel, that the contact is affiliated with, as stated above. (Figure 3.5.2.1).

Figure 3.5.2.1 : Graphical User interface for profile

3.6.3. Design Considerations

Aspect: The usage of YouTuber channel ID or username to retrieve channel information.
Alternative 1 (current choice): Use YouTube channel ID.
Pros: There is a unique ID for each YouTube channel.
Cons: User would need to copy and paste the uniquely generated channel ID as it would be very inconvenient to type in each individual character.
Alternative 2: Use YouTube Username.
Pros: Might be more intuitive for the user and easier to type in.
Cons: There are so many channels with the same highly sought after names (sans the bigger channels). Although it will be easier for the user to type in as most channel names are easy to read, the user might confuse the channel title with the channel username (both are often mistaken as the same thing), resulting in the wrong channel being saved.

3.7. Favourites mechanism

The Favourites mechanism is facilitated by a 'favourite' boolean variable, which resides inside Person. It flags each 'Person' object as either a favourite, or not one.

public class FavCommand extends UndoableCommand {
    @Override
    public CommandResult executeUndoableCommand() {
        try {
            model.favPerson(personToFave, status);
            } catch (DuplicatePersonException dpe) {
                assert false : "The target person cannot be already in the favourites list";
            } catch (PersonNotFoundException pnfe) {
                assert false : "The target person cannot be found";
            }

        if (status == true){
            return new CommandResult(String.format(MESSAGE_FAVE_PERSON_SUCCESS, personToFave));
        }

        else {
            return new CommandResult(String.format(MESSAGE_UNFAVE_PERSON_SUCCESS, personToFave));
        }

    }
}

Suppose that the user has just launched the application for the first time. All 'Person' models will have 'false' as their 'favourite' boolean variable..

The user executes a new FavCommand, 1 true, to mark the first person on the displayed list as a favourite. Should he then execute 'fave 1 false', that first person will no longer be marked as a favourite.

ℹ️	If a command fails its execution, the person’s 'favourite' boolean variable will not change.

ℹ️	If the person is already marked as a favourite, and the person attempts to mark it as a favourite, the command will throw an error. However, if the person is not a favourite and the user marks the person as not a favourite, the command will be successful.

ℹ️	FavCommand is an UndoableCommand.

3.7.1. Design Considerations

Aspect: Implementation of UndoableCommand
Alternative 1 (current choice): Add new class FavCommand()
Pros: Will have similar structure to other commands, and preserve consistency in implementation.
Cons: Many new classes will have to be created to support this class, e.g. parsers, tests etc.
Alternative 2: Just add a favourite tag alias`
Pros: Little to no effort to implement.
Cons: Future functionality based on the favourites list will be harder to implement.

Aspect: How undo & redo executes
Alternative 1 (current choice): Modifies a variable in the Person model.
Pros: Automatically saved, easy to access data.
Cons: Adds additional memory requirements to each Person model.
Alternative 2: Add a tag called 'favourite' to target Person.
Pros: No new classes needed, easy to implement.
Cons: Difficult to build additional functionality based on favourites list.

Aspect: Make FavCommand() Undoable
Alternative 1 (current choice): FavCommand() is Undoable.
Pros: Easy to quickly revert mistakes.
Cons: User might think that undo also applies when the list is modified (undoing filtering for example), only to realize that it does not do that, after executing undo.
Alternative 2: FavCommand() is not Undoable
Pros: Might be more intuitive for the user.
Cons: Much longer command will need to be entered to revert any mistake.

3.8. Live Help

The live help feature aims to provide an alternative form of help window to the user. As the user types into the CommandBox, a possible list of commands with its usage is displayed in the ResultDisplay.

This feature works by searching across all the commands to find possible commands that the user might be using. For example, typing find will result in the ResultDisplay showing help for find, findtag and findemail commands.

The liveHelp method resides in LogicManager which retrieves the entered text from the CommandBox and passes the text into the filterCommand inside AddressBookParser. The filterCommand retrieves all possible commands that the user might be finding by checking if any COMMAND_WORD contains the entered word. The array of possible results is returned to the liveHelp method and is concatenated into a string which is displayed in the ResultDisplay.+ The following sequence diagram illustrates the flow of the live help feature.

Figure 3.7.1: Sequence Diagram for Live Help feature

The filterCommand inside AddressBookParser employs the use of HashMap to store all the command words and the help for each command. This allows for a cleaner code as it removes the long if else statements by using a for loop to iterate through the entire list of commands.

for (HashMap.Entry<String, String> entry : commandList.entrySet()) {
    if (isExact) {
        if (entry.getKey().equals(array[0])) {
            result.add(entry.getKey());
        }
    } else {
        if (entry.getKey().contains(array[0])) {
            result.add(entry.getValue());
        }
    }
}

Furthermore, creating a boolean isExact allows for this method to also be used to check if a string is exactly a command word.
By setting isExact to false, this method will return all command words that contains the entered text.
By setting isExact to true, this method will return all command words that is equals to the entered text. Hence, this reduces the need for another method.

public ArrayList<String> filterCommand(String text, boolean isExact) throws IllegalValueException {
    //Code
}

3.8.1. Design Considerations

Aspect: Parsing the entered string
Alternative 1 (current choice): Store all the commands in a HashMap and iterate through the HashMap to compare each command word with the entered string.
Pros: This implementation provides a cleaner code. Hence it is easier read and to add additional search functionality. For instance, only 1 if else is required to switch between finding if the command word is equals to the entered word or if the command contains the entered word
Cons: None.

Alternative 2: Use switch case statements to code the logic for each command.
Pros: Straightforward. Easy to implement if there are only a few commands.
Cons: Tedious and time consuming. Having additional conditions like isExact means having to duplicate the entire switch case.

3.9. Logging

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 Configuration)
The Logger for a class can be obtained using LogsCenter.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

3.10. Configuration

Certain properties of the application can be controlled (e.g App name, logging level) through the configuration file (default: config.json).

4. Documentation

We use asciidoc for writing documentation.

ℹ️	We chose asciidoc over Markdown because asciidoc, although a bit more complex than Markdown, provides more flexibility in formatting.

4.1. Editing Documentation

See UsingGradle.adoc to learn how to render .adoc files locally to preview the end result of your edits. Alternatively, you can download the AsciiDoc plugin for IntelliJ, which allows you to preview the changes you have made to your .adoc files in real-time.

4.2. Publishing Documentation

See UsingTravis.adoc to learn how to deploy GitHub Pages using Travis.

4.3. Converting Documentation to PDF format

We use Google Chrome for converting documentation to PDF format, as Chrome’s PDF engine preserves hyperlinks used in webpages.

Here are the steps to convert the project documentation files to PDF format.

Follow the instructions in UsingGradle.adoc to convert the AsciiDoc files in the docs/ directory to HTML format.
Go to your generated HTML files in the build/docs folder, right click on them and select Open with → Google Chrome.
Within Chrome, click on the Print option in Chrome’s menu.
Set the destination to Save as PDF, then click Save to save a copy of the file in PDF format. For best results, use the settings indicated in the screenshot below.

Figure 5.6.1 : Saving documentation as PDF files in Chrome

5. Testing

5.1. Running Tests

There are three ways to run tests.

💡	The most reliable way to run tests is the 3rd one. The first two methods might fail some GUI tests due to platform/resolution-specific idiosyncrasies.

Method 1: Using IntelliJ JUnit test runner

To run all tests, right-click on the src/test/java folder and choose Run 'All Tests'
To run a subset of tests, you can right-click on a test package, test class, or a test and choose Run 'ABC'

Method 2: Using Gradle

Open a console and run the command gradlew clean allTests (Mac/Linux: ./gradlew clean allTests)

ℹ️	See UsingGradle.adoc for more info on how to run tests using Gradle.

Method 3: Using Gradle (headless)

Thanks to the TestFX library we use, our GUI tests can be run in the headless mode. In the headless mode, GUI tests do not show up on the screen. That means the developer can do other things on the Computer while the tests are running.

To run tests in headless mode, open a console and run the command gradlew clean headless allTests (Mac/Linux: ./gradlew clean headless allTests)

5.2. Types of tests

We have two types of tests:

GUI Tests - These are tests involving the GUI. They include,
1. System Tests that test the entire App by simulating user actions on the GUI. These are in the systemtests package.
2. Unit tests that test the individual components. These are in seedu.address.ui package.
Non-GUI Tests - These are tests not involving the GUI. They include,
1. Unit tests targeting the lowest level methods/classes.
  e.g. seedu.address.commons.StringUtilTest
2. Integration tests that are checking the integration of multiple code units (those code units are assumed to be working).
  e.g. seedu.address.storage.StorageManagerTest
3. Hybrids of unit and integration tests. These test are checking multiple code units as well as how the are connected together.
  e.g. seedu.address.logic.LogicManagerTest

5.3. Troubleshooting Testing

Problem: HelpWindowTest fails with a NullPointerException.

Reason: One of its dependencies, UserGuide.html in src/main/resources/docs is missing.
Solution: Execute Gradle task processResources.

6. Dev Ops

6.1. Build Automation

See UsingGradle.adoc to learn how to use Gradle for build automation.

6.2. Continuous Integration

We use Travis CI and AppVeyor to perform Continuous Integration on our projects. See UsingTravis.adoc and UsingAppVeyor.adoc for more details.

6.3. Making a Release

Here are the steps to create a new release.

Update the version number in MainApp.java.
Generate a JAR file using Gradle.
Tag the repo with the version number. e.g. v0.1
Create a new release using GitHub and upload the JAR file you created.

6.4. Managing Dependencies

A project often depends on third-party libraries. For example, Address Book depends on the Jackson library for XML parsing. Managing these dependencies can be automated using Gradle. For example, Gradle can download the dependencies automatically, which is better than these alternatives.
a. Include those libraries in the repo (this bloats the repo size)
b. Require developers to download those libraries manually (this creates extra work for developers)

Appendix A: Suggested Programming Tasks to Get Started

Suggested path for new programmers:

First, add small local-impact (i.e. the impact of the change does not go beyond the component) enhancements to one component at a time. Some suggestions are given in this section Improving a Component.
Next, add a feature that touches multiple components to learn how to implement an end-to-end feature across all components. The section Creating a new command: remark explains how to go about adding such a feature.

A.1. Improving each component

Each individual exercise in this section is component-based (i.e. you would not need to modify the other components to get it to work).

`Logic` component

💡	Do take a look at the Design: Logic Component section before attempting to modify the `Logic` component.

Add a shorthand equivalent alias for each of the individual commands. For example, besides typing clear, the user can also type c to remove all persons in the list.
- Hints
  
  Just like we store each individual command word constant COMMAND_WORD inside *Command.java (e.g. FindCommand#COMMAND_WORD, DeleteCommand#COMMAND_WORD), you need a new constant for aliases as well (e.g. FindCommand#COMMAND_ALIAS).
  
  AddressBookParser is responsible for analyzing command words.
- Solution
  
  Modify the switch statement in AddressBookParser#parseCommand(String) such that both the proper command word and alias can be used to execute the same intended command.
  
  See this PR for the full solution.

`Model` component

💡	Do take a look at the Design: Model Component section before attempting to modify the `Model` component.

Add a removeTag(Tag) method. The specified tag will be removed from everyone in the address book.
- Hints
  
  The Model API needs to be updated.
  
  Find out which of the existing API methods in AddressBook and Person classes can be used to implement the tag removal logic. AddressBook allows you to update a person, and Person allows you to update the tags.
- Solution
  
  Add the implementation of deleteTag(Tag) method in ModelManager. Loop through each person, and remove the tag from each person.
  
  See this PR for the full solution.

`Ui` component

💡	Do take a look at the Design: UI Component section before attempting to modify the `UI` component.

Use different colors for different tags inside person cards. For example, friends tags can be all in grey, and colleagues tags can be all in red.

Before

After
- Hints
  
  The tag labels are created inside PersonCard#initTags(ReadOnlyPerson) (new Label(tag.tagName)). JavaFX’s Label class allows you to modify the style of each Label, such as changing its color.
  
  Use the .css attribute -fx-background-color to add a color.
- Solution
  
  See this PR for the full solution.
Modify NewResultAvailableEvent such that ResultDisplay can show a different style on error (currently it shows the same regardless of errors).

Before

After
- Hints
  
  NewResultAvailableEvent is raised by CommandBox which also knows whether the result is a success or failure, and is caught by ResultDisplay which is where we want to change the style to.
  
  Refer to CommandBox for an example on how to display an error.
- Solution
  
  Modify NewResultAvailableEvent 's constructor so that users of the event can indicate whether an error has occurred.
  
  Modify ResultDisplay#handleNewResultAvailableEvent(event) to react to this event appropriately.
  
  See this PR for the full solution.
Modify the StatusBarFooter to show the total number of people in the address book.

Before

After
- Hints
  
  StatusBarFooter.fxml will need a new StatusBar. Be sure to set the GridPane.columnIndex properly for each StatusBar to avoid misalignment!
  
  StatusBarFooter needs to initialize the status bar on application start, and to update it accordingly whenever the address book is updated.
- Solution
  
  Modify the constructor of StatusBarFooter to take in the number of persons when the application just started.
  
  Use StatusBarFooter#handleAddressBookChangedEvent(AddressBookChangedEvent) to update the number of persons whenever there are new changes to the addressbook.
  
  See this PR for the full solution.

`Storage` component

💡	Do take a look at the Design: Storage Component section before attempting to modify the `Storage` component.

Add a new method backupAddressBook(ReadOnlyAddressBook), so that the address book can be saved in a fixed temporary location.
- Hint
  
  Add the API method in AddressBookStorage interface.
  
  Implement the logic in StorageManager class.
- Solution
  
  See this PR for the full solution.

A.2. Creating a new command: `remark`

By creating this command, you will get a chance to learn how to implement a feature end-to-end, touching all major components of the app.

A.2.1. Description

Edits the remark for a person specified in the INDEX.
Format: remark INDEX r/[REMARK]

Examples:

remark 1 r/Likes to drink coffee.
Edits the remark for the first person to Likes to drink coffee.
remark 1 r/
Removes the remark for the first person.

A.2.2. Step-by-step Instructions

[Step 1] Logic: Teach the app to accept 'remark' which does nothing

Let’s start by teaching the application how to parse a remark command. We will add the logic of remark later.

Main:

Add a RemarkCommand that extends UndoableCommand. Upon execution, it should just throw an Exception.
Modify AddressBookParser to accept a RemarkCommand.

Tests:

Add RemarkCommandTest that tests that executeUndoableCommand() throws an Exception.
Add new test method to AddressBookParserTest, which tests that typing "remark" returns an instance of RemarkCommand.

[Step 2] Logic: Teach the app to accept 'remark' arguments

Let’s teach the application to parse arguments that our remark command will accept. E.g. 1 r/Likes to drink coffee.

Main:

Modify RemarkCommand to take in an Index and String and print those two parameters as the error message.
Add RemarkCommandParser that knows how to parse two arguments, one index and one with prefix 'r/'.
Modify AddressBookParser to use the newly implemented RemarkCommandParser.

Tests:

Modify RemarkCommandTest to test the RemarkCommand#equals() method.
Add RemarkCommandParserTest that tests different boundary values for RemarkCommandParser.
Modify AddressBookParserTest to test that the correct command is generated according to the user input.

[Step 3] Ui: Add a placeholder for remark in `PersonCard`

Let’s add a placeholder on all our PersonCard s to display a remark for each person later.

Main:

Add a Label with any random text inside PersonListCard.fxml.
Add FXML annotation in PersonCard to tie the variable to the actual label.

Tests:

Modify PersonCardHandle so that future tests can read the contents of the remark label.

[Step 4] Model: Add `Remark` class

We have to properly encapsulate the remark in our ReadOnlyPerson class. Instead of just using a String, let’s follow the conventional class structure that the codebase already uses by adding a Remark class.

Main:

Add Remark to model component (you can copy from Address, remove the regex and change the names accordingly).
Modify RemarkCommand to now take in a Remark instead of a String.

Tests:

Add test for Remark, to test the Remark#equals() method.

[Step 5] Model: Modify `ReadOnlyPerson` to support a `Remark` field

Now we have the Remark class, we need to actually use it inside ReadOnlyPerson.

Main:

Add three methods setRemark(Remark), getRemark() and remarkProperty(). Be sure to implement these newly created methods in Person, which implements the ReadOnlyPerson interface.
You may assume that the user will not be able to use the add and edit commands to modify the remarks field (i.e. the person will be created without a remark).
Modify SampleDataUtil to add remarks for the sample data (delete your addressBook.xml so that the application will load the sample data when you launch it.)

[Step 6] Storage: Add `Remark` field to `XmlAdaptedPerson` class

We now have Remark s for Person s, but they will be gone when we exit the application. Let’s modify XmlAdaptedPerson to include a Remark field so that it will be saved.

Main:

Add a new Xml field for Remark.
Be sure to modify the logic of the constructor and toModelType(), which handles the conversion to/from ReadOnlyPerson.

Tests:

Fix validAddressBook.xml such that the XML tests will not fail due to a missing <remark> element.

[Step 7] Ui: Connect `Remark` field to `PersonCard`

Our remark label in PersonCard is still a placeholder. Let’s bring it to life by binding it with the actual remark field.

Main:

Modify PersonCard#bindListeners() to add the binding for remark.

Tests:

Modify GuiTestAssert#assertCardDisplaysPerson(…) so that it will compare the remark label.
In PersonCardTest, call personWithTags.setRemark(ALICE.getRemark()) to test that changes in the Person 's remark correctly updates the corresponding PersonCard.

[Step 8] Logic: Implement `RemarkCommand#execute()` logic

We now have everything set up… but we still can’t modify the remarks. Let’s finish it up by adding in actual logic for our remark command.

Main:

Replace the logic in RemarkCommand#execute() (that currently just throws an Exception), with the actual logic to modify the remarks of a person.

Tests:

Update RemarkCommandTest to test that the execute() logic works.

A.2.3. Full Solution

See this PR for the step-by-step solution.

Appendix B: User Stories

Priorities: High (must have) - * * *, Medium (nice to have) - * *, Low (unlikely to have) - *

Priority	As a …	I want to …	So that I…
`* * *`	new user	see usage instructions.	refer to instructions when I forget how to use the App.
`* * *`	user	see information of the YouTube channel of the contact along with the rest of their contact information	can easily refer to information on their YouTube channel when looking at their contact information and vice versa.
`* * *`	user	add a person.	save the contact information of my contacts.
`* * *`	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	click a link to access files sent to me by a contact.	do not have to search my email/dropbox for it.
`* * *`	user	import contacts from other addressbook apps.	do not have to re-enter each contact manually.
`* * *`	user	add contacts to a favourites list.	can access those contacts more easily.
`* * *`	user	access their social media profile through the addressbook.	do not have to search for their profile.
`* * *`	user	check my commands history.	can recall what I did.
`* * *`	user	undo my previous commands.	can revert my mistakes.
`* * *`	user	hide private contact details.	prevent someone else from seeing them by accident.
`* * *`	user	keep track of multiple phone numbers from different countries.	do not have multiple entries for the same person.
`* * *`	user	sign in with email/password	can stop others from access my addressbook.
`* * *`	user	list all the contacts with a command.	can view the entire contacts at once.
`* * *`	user	block certain contacts from sending messages or viewing my profile.	will not be disturbedby spammers.
`* * *`	user	reformat with a command and a password.	can clear all contacts faster.
`* * *`	user	add descriptive comments to a contact.	am able to keep track of who that person is.
`* *`	user	hide private contact details by default.	minimize chance of someone else seeing them by accident.
`* *`	user	add photos to contacts.	can recognise the name easily.
`* *`	user	set a reminder that will prompt me about upcoming events with the contact.	will not forget significant events.
`* *`	user	see the map of contact’s address if they share it.	can find my way there more easily.
`* *`	user	set up an online profile.	can change my number and other people can still contact me.
`* *`	user	view the contacts that I have recently contacted.	can view people whom I have recently contacted but not saved their number.
`* *`	user	keep my preferences of listing contacts.	do not have to set the options again.
`* *`	user	send messages/emails to contacts within the addressbook.	do not have to leave the addressbook to send messages/emails.
`* *`	user	create shortcuts for long messages.	do not need to type everything out.
`* *`	user	indicate my availability by hightlighting my name with certain color on other’s people addressbook.	can show other’s my status.
`* *`	user	edit contact’s information.	can keep my contact details updated.
`* *`	user	send commands in natural language.	do not have to follow a fix input structure.
`* *`	user	revert to a previous point in history.	undo multiple mistakes.
`* *`	user	set an alias for commands or strings.	do not have to type everything out.
`*`	user	copy the details of my contacts to a message or email.	can share a contact with other contacts easily.
`*`	user with many persons in the address book	sort persons by name.	locate a person easily.

Appendix C: Use Cases

(For all use cases below, the System is the AddressBook and the Actor is the user, unless specified otherwise)

Use case: Delete person

MSS

User requests to list persons
AddressBook shows a list of persons
User requests to delete a specific person in the list
AddressBook deletes the person

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
3a. The given index is invalid.
- 3a1. AddressBook shows an error message.
  
  Use case resumes at step 2.

Use case: Send messages to other contacts

MSS

User requests to list persons
AddressBook shows a list of persons
User requests to send a message to a specific person in the list using either WhatsApp or Email
AddressBook opens the requested application depending on the user’s input

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
3a. The given index is invalid.
- 3a1. AddressBook shows an error message.
  
  Use case resumes at step 2.
3b. Contact does not contain contact information for method chosen by user.
- 3b1. AddressBook shows an error message.
  
  Use case resumes at step 2.

MSS

User requests to list persons
AddressBook shows a list of persons
User requests to copy details of a specific contact
AddressBook shows the details of the contact
User copies the details onto his or her clipboard

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
3a. The given index is invalid.
- 3a1. AddressBook shows an error message.
  
  Use case resumes at step 2.

MSS

User requests to list persons
AddressBook shows a list of persons
User requests to access one of the social media profiles of a specified contact
AddressBook opens the requested social media profile of the contact

Use case ends.

Extensions

2a. The list is empty.

Use case ends.
3a. The given index is invalid.
- 3a1. AddressBook shows an error message.
  
  Use case resumes at step 2.
3b. The contact’s details do not include information for the social media profile requested by the user.
- 3b1. AddressBook shows an error message.
  
  Use case resumes at step 2.

Appendix D: Non Functional Requirements

Should work on any mainstream OS as long as it has Java 1.8.0_60 or higher installed.
Should be able to hold up to 1000 persons without a noticeable sluggishness in performance for typical usage.
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.
Each version of the application should be backwards compatible with contacts created and saved using the previous versions.
Should offer encrypted user passwords for additional security.
The project is not required to handle server-side data storage.
The system should be usable by a user with no prior experience with programming languages.
The system should have a colour scheme that is friendly to colour-blind users.
The system should be fully usable without needing to touch the mouse.
The system should respond within two seconds.

Appendix E: Glossary

Backward compatible

Current version of the AddressBook is able to run previous version of the AddressBook successfully.

Commands

Instruction to tell the AddressBook what to do in order to perform specific task, such as storing or deleting a contact.

Dynamic information

Refers to information that is automatically retrieved from the YouTube servers and updated every time the user views the profile of the contact.

Mainstream OS

Windows, Linux, Unix, OS-X

Natural Language

Refers to the language use by human, such as English, Chinese, Spanish, French etc..
It is different from language use by Artificial Intelligence and Computer.

Private contact detail

A contact detail that is not meant to be shared with others

Programming Language

A vocabulary and set of grammatical rules for instructing a computer or computing device to perform certain task.
Some common programming languages are Java, C, C++, Python etc.

Reformat

The process of erasing every data and reset it back to its original form.
Usually perform when data is corrupted, or for convenience when there are too many datas to be deleted.

Server

A computer created to process request and deliver data to other computers over a local network or the internet.

Server-side data storage

Refers to an online storage medium for storing your data. Requires a server to do so, such as Cloud server.

Version

A way to categorize the current state of a software as it is developed and released.
One has to note that there is no industry standard for how a version number should be formatted.
Therefore, different companies/developers have different style of formatting version number.

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TABCC (The Address Book for Content Creators) - Developer Guide

1. Setting up

1.1. Prerequisites

1.2. Setting up the project in your computer

1.3. Verifying the setup

1.4. Configurations to do before writing code

1.4.1. Configuring the coding style

1.4.2. Updating documentation to match your fork

1.4.3. Setting up CI

1.4.4. Getting started with coding

2. Design

2.1. Architecture

Events-Driven nature of the design

2.2. UI component

2.3. Logic component

2.4. Model component

2.5. Storage component

2.6. Common classes

3. Implementation

3.1. Lock Screen

3.1.1. Design Considerations

3.2. FindEmailCommand

3.3. FavCommand

3.4. FindFavCommand

3.5. Undo/Redo mechanism

3.5.1. Design Considerations

3.6. Select command

3.6.1. Dynamic information:

3.6.2. Profile GUI

3.6.3. Design Considerations

3.7. Favourites mechanism

3.7.1. Design Considerations

3.8. Live Help

3.8.1. Design Considerations

3.9. Logging

3.10. Configuration

4. Documentation

4.1. Editing Documentation

4.2. Publishing Documentation

4.3. Converting Documentation to PDF format

5. Testing

5.1. Running Tests

5.2. Types of tests

5.3. Troubleshooting Testing

6. Dev Ops

6.1. Build Automation

6.2. Continuous Integration

6.3. Making a Release

6.4. Managing Dependencies

Appendix A: Suggested Programming Tasks to Get Started

A.1. Improving each component

Logic component

Model component

Ui component

Storage component

A.2. Creating a new command: remark

A.2.1. Description

A.2.2. Step-by-step Instructions

[Step 1] Logic: Teach the app to accept 'remark' which does nothing

[Step 2] Logic: Teach the app to accept 'remark' arguments

[Step 3] Ui: Add a placeholder for remark in PersonCard

[Step 4] Model: Add Remark class

[Step 5] Model: Modify ReadOnlyPerson to support a Remark field

[Step 6] Storage: Add Remark field to XmlAdaptedPerson class

[Step 7] Ui: Connect Remark field to PersonCard

[Step 8] Logic: Implement RemarkCommand#execute() logic

A.2.3. Full Solution

Appendix B: User Stories

Appendix C: Use Cases

Use case: Delete person

Use case: Send messages to other contacts

Use case: Copy contact details for sharing

Use case: Access contact’s social media profiles

Appendix D: Non Functional Requirements

`Logic` component

`Model` component

`Ui` component

`Storage` component

A.2. Creating a new command: `remark`

[Step 3] Ui: Add a placeholder for remark in `PersonCard`

[Step 4] Model: Add `Remark` class

[Step 5] Model: Modify `ReadOnlyPerson` to support a `Remark` field

[Step 6] Storage: Add `Remark` field to `XmlAdaptedPerson` class

[Step 7] Ui: Connect `Remark` field to `PersonCard`

[Step 8] Logic: Implement `RemarkCommand#execute()` logic