AddressBook Level 4 - Developer Guide

By: Team SE-EDU Since: Jun 2016 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 its 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 MainWindow that is made up of parts e.g.CommandBox, ResultDisplay, PersonListPanel, TaskListPanel, 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> and ObservableList<ReadOnlyTask> 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. Google Implementation

Contact’em now incorporates and integrates Google Contacts and Gmail which will enhance its usability. Firstly, Login Command is implemented so that the Contact’em can authenticate with the google servers when the user has successfully logged in. The new GoogleAuthenticator class is created to run the authentication process.

The Login Command sequence diagram is as follows:

Figure 3.1.1 : Login command sequence diagram

The login page will be loaded in the browser panel after the login command has successfully executed. This is for the user to authenticate with google. Contact’em will then redirect the user to the Google contacts web page after successful authentication.

3.1.1. GoogleContactsBuilder class and GoogleID attribute

The GoogleContactsBuilder class can be instantiated to access the list of contacts from Google and also to obtain the PeopleService object needed to modify the contacts in Google. This is done by making use of the methods in the GoogleAuthenticator object to obtain the access token and PeopleService from Google.

The token required for authentication is obtained from the redirect url after logging in. This means that the user must stay on the Google contacts page in the browser panel when instantiating this class (For import / export / sync commands). The class diagram for GoogleContactsBuilder is shown below.

Figure 3.1.1.1 : GoogleContactsBuilder class diagram

Every Person in the address book now has a new attribute known as the GoogleID. This ID refers to its own GoogleID in Google contacts. Contacts that are not synchronised with Google will have a null GoogleID.

3.1.2. Import Command

After successful authentication, the user can proceed to import contacts from his google account. The import command creates a GoogleContactsBuilder object to retrieve the list of google contacts from the server.

The Import command sequence diagram is as follows:

Figure 3.1.2.1 : Import command sequence diagram

When the command is executed, the list of Google contacts will be looped through and compared with the contacts in Contact’em. If the GoogleID of a particular Google contact is not found in Contact’em, the contact will be imported. This is represented by the code snippet as shown below.

Pseudo-code snippet:

for each contact: googleContactsList {
    if contact does not exists in Contact’em
               model.addPerson(newPerson(contact))
}

Scenario 1

The newPerson(…) method shown in the above code snippet successfully creates a Person object using attributes from the Google contact and it will be added to the address book. The GoogleID of the contact will also be instantiated within the new Person Object. The Person will also be given a GoogleContact Tag.

Scenario 2

The newPerson(…) method fails to create a Person object from the Google contact. The Google contact will fail to import. Reasons for the above mentioned failure includes,
1) Google contact might have invalid attributes. Eg: Invalid email format
2) Google contact might not have all attributes required to create a new Person object. All the following attributes must be present: Name, Phone, Email and Address.

A message detailing the result of the command will be displayed to inform the user on the number of contacts imported or the number of contacts along with a string of names of contacts that failed to import.

3.1.3. Export Command

After successful authentication, the user can next proceed to export contacts from Contact’em into his google account. The command creates a GoogleContactsBuilder object to retrieve peopleService from google which is required to modify/add contacts in Google.

The Export command sequence diagram is as follows:

Figure 3.1.3.1 : Export command sequence diagram

When the command is executed, the list of contacts in Contact’em will be looped through to check whether they are a google contact. If they are not, they will be exported to Google contacts. This is represented by the code snippet shown below.

Pseudo-code snippet

for each contact: addressBookList{
    if contact does not have a GoogleContact Tag
               New googleContact = createGoogleContact (contact);
               googleContact = builder.getPeopleService().people() createContact(googleContact).
                                            execute();
               model.updatePerson(contact, newAddressBookContact(contact));
}

Scenario 1

The createGoogleContact method shown in the above code snippet successfully creates a GooglePerson that will be exported to Google contacts. The export command will then update the contact by instantiating its GoogleID attribute retrieved from the newly created Google contact and adding a GoogleContacts tag to it.

Scenario 2

The contact might not be exported to Google due to the failure in connecting to Google servers. This is can be due to token expiring.

A message detailing the result of the command will be displayed to inform the user on the number of contacts imported or failed to import.

3.1.4. Sync Command

After successful authentication, the user can proceed to sync contacts in Contact’em. The sync command creates a GoogleContactsBuilder object to retrieve the list of Google contacts from the server. In this case, the contacts in Google contacts takes higher precedence and any changes to them will be updated to the contacts in Contact’em when the user syncs. However, any changes made to the contacts in the Contact’em will not be transferred to Google contacts when the user syncs but instead, its attribute will be restored to its original value.

The Sync command sequence diagram is as follows:

Figure 3.1.4.1 : Sync command sequence diagram

When the command is executed, the list of contacts in Contact’em will be looped through to check if they exists within the list of Google contacts. If they are, a Person object based on the Google contact will be created and it will be used to compare with the contact in the Contact’em. This is represented by the code snippet shown below.

Pseudo-code snippet:

for each contact: addressBookList{
    for each googlecontact : googleContactsList{
               if contact shares a similar googleID with the googlecontact
               exists = true;
                          if convertToAddress(googlecontact) is not the same as contact
                                    model.updatePerson(contact, convertToAddress(googlecontact))
     }
    if contact is a google contact but exists == false
                model.updatePerson(contact, removeGoogleContactStatus(contact));
}

Scenario 1

The attributes of the contact are the same as itself in Google contacts. No synchronising will be done on that contact.

Scenario 2

The attributes of the contact are different from itself in Google contacts. A newly created contact will replace the previous contact as shown in the above code snippet in model.updatePerson(…).

Scenario 3

The format of the Google contact is invalid and hence no new Person is created for comparison with the contact in Contact’em. The contact in the Contact’em will not be synchronised.

Scenario 4

The contact in the Contact’em is thought to exist in Google contacts but is not found. The removeGoogleContactStatus() method shown in the above code snippet will remove the Google contact status of the contact.

A message detailing the result of the command will be displayed to inform the user on the number of contacts synced and the number of contacts along with a string of names of contacts that failed to sync.

3.1.5. Design Considerations

Aspect: Storage of access token.
Alternative 1 (current choice): Users have to be on the Google contact web page in order to use the following commands : Import, Export, Sync. This is because the token is retrieved from the url every time the user uses the above mentioned commands.
Pros: Users will be able to inspect the contacts within the Google contacts and they will be able to update the contacts if the contacts fail to import or synchronise by referring to the warning messages displayed.
Cons: This might cause some inconvenience because the users have to re-login to use the above mentioned commands if they have switched pages in the browser panel.
Alternative 2: Stores the token within the program once the user has logged in.
Pros: More convenience for user as they do not have to stay on the Google contacts page whenever they want to use the above mentioned commands.
Cons: In the case when some contacts fail to synchronise or import, the user have to re-login anyway to check on the contacts in google. By doing so, the error message produced earlier on will be removed and the user does not have a reference to see which contact is not importing or synchronising.

Aspect: Precedence of Google contacts over Contact’em contacts in sync command
Alternative 1 (current choice): Google contacts takes higher precedence. Contacts updated in Google contacts will be synchronised to Contact’em.
Pros: This alternative allow users to update contacts in Google contacts on-the-go which can be synchronised to Contact’em next time they use it.
Cons: Contacts updated in Contact’em must be manually updated in the Google contacts as well. If not, next time when the user synchronises Contact’em, the changes will be removed.
Alternative 2: Contact’em takes higher precedence. Contacts updated in Contact’em will be synchronised to Google contacts.
Pros: This is better for user who uses Contact’em more often than Google contacts. For some, the contacts in Google contacts might just be an on-the-go reference and most updating is done within Contact’em.
Cons: Will not be able to update contacts if they are away from the computer.

3.2. EasyFind mechanism

The EasyFind mechanism is an action driven task, which activates when the user tries to search for a contact by updating the search results whenever the user inputs a letter into the command box.

The mechanism is facilitated by a new command FindLettersCommand which will search for contacts matching the letters in the command box. The command is called every time the user inputs or remove a character from the command box while using the command Find.

The key release event of the command box is constantly searching for the term find and when the user inputs the mentioned term into the command box, the key release event will begin searching for contacts by passing the letters entered after the term find into FindLettersCommand.

The application will display the number of contacts that share the same letters as the input.

ℹ️	After the user inputs `enter`, normal find command will be executed

ℹ️	EasyFind mechanism is case insensitive

The following sequence diagram shows how the FindLettersCommand works:

Figure 3.2.1 : FindLettersCommand sequence diagram

3.2.1. Design Considerations

Aspect: Intertwining of FindLettersCommand and FindCommand
Alternative 1 (current choice): Separate both commands.
Pros: We will not lose the original functionality of the FindCommand and creating a new FindLettersCommand allows the application to search for contacts more frequently when the EasyFind mechanism is activated.
Cons: This might confuse the user as the FindCommand and FindLettersCommand could generate different results. The contact that the user is searching for may be displayed when a partial name is inputted. However, when the user inputs enter before typing in the full name, the displayed contact will be removed by the original FindCommand
Alternative 2: Replace FindCommand with FindLettersCommand
Pros: The results displayed will not change even after the user has pressed enter. It can also help the user to speed up the process of searching for contacts as they user does not have to input the full name
Cons: Removing the find Command may affect other functions of Contact’em.

3.3. Finding Contacts by Tags

The application allows users to find contacts based on their tags. The command word is findtags, and the alternatives are findtag and ft. The following subsections explain how the program is supposed to function given this command, and how it is implemented.

3.3.1. User Inputs and Expected Actions/Results

There are three ways to use this command. Some pseudo-code is provided for each of these 3 scenarios to aid understanding.

Scenario 1

In the first scenario, also the most basic, the user only specifies tags to include. For this, the program should simply return all contacts that have at least one of the tags.

Example Command 1: findtags friends
Expected result: returns contacts that are tagged “friends”.

Pseudo-code snippet

for each tag : contact.getTagList {
    if (keywordsToInclude.hasAnyMatchingWordsWith(tag.value)) {
        return true;
    }
}
return false;

Scenario 2

In the second scenario, the user only specifies tags to exclude. To specify a tag to exclude, user includes a hyphen "-" before the keyword to be excluded. In this case, the program should return all contacts that do not have any of these tags to be excluded.

Note that this includes contacts with no tags.

Example Command 2: findtags -colleagues
Expected result: returns all contacts not tagged “colleagues”.

Pseudo-code snippet

for each tag : contact.getTagList {
    if (keywordsToExclude.hasAnyMatchingWordsWith(tag.value)) {
        return false;
    }
}
return true;

Scenario 3

In the third scenario, the user specifies both tags to include and exclude. The program will return all contacts that have:
1) ANY of the tags to include.
2) NONE of the tags to exclude.

Example Command 3: findtags friends -colleagues
Expected result: returns all contacts tagged “friends” but not tagged “colleagues”.

Pseudo-code snippet:

boolean personHasAtLeastOneMatchingTag = false;

for each tag : contact.getTagList {
     if keywordsToExclude.hasAnyMatchingWordsWith(tag.value)
                return false;
     if keywordsToInclude.hasAnyMatchingWordsWith(person.getTagList()
                 personHasAtLeastOneMatchingTag = true;
}

if (personHasAtLeastOneMatchingTag)
      return true;
else
      return false;

ℹ️	There must be at least one parameter specified, but the order of parameters entered does not matter.

3.3.2. Brief Overview of Command Procedure

3 diagrams are provided below to help illustrate a big picture view of the command.

Class Diagram:

Figure 3.3.2.1 : Class Diagram of Find Tags Command

Firstly, Figure 3.3.2.1 above is the class diagram of this command, which should provide a basic understanding of the classes involved.

Activity Diagram:

Figure 3.3.2.2 : Brief Overview of Find Tags Command Procedure

Secondly, Figure 3.3.2.2 above is the activity diagram of the command. As you can see, the entire command consists of 4 main steps:

1) The parameters are parsed and deciphered.
2) Using the deciphered information from step 1, the Predicate and Command are constructed.
3) Command is executed.
4) Predicate is called and the Model is updated.

More detailed explanations and elaborations are given in the subsections below.

Sequence Diagram:

Figure 3.3.2.3 : Findtags Sequence Diagram

Last but not least, Figure 3.3.2.3 above shows the overall sequence diagram, to give a more detailed look into the steps taken by the program to run the command.

3.3.3. Implementation of Parser

The parser associated with this command is FindPersonsWithTagsCommandParser, under seedu.address.logic.parser. Due to this parser’s long name, it will be referred to as the “command parser” or simply “parser” within this section to aid clarity.

When this command is invoked by the user, this command parser will be constructed by AddressbookParser, receiving the user’s input as a String parameter. The command parser deciphers the input, and eventually returns a FindPersonsWithTagsCommand for execution.

The command parser first checks if the arguments are valid. If the arguments are empty, a ParseException will be thrown for invalid arguments. If the arguments are valid (non-empty), they are split into individual keywords and stored in a String array tagKeywords.

Figure 3.3.3.1 : Splitting Up Keywords

As the diagram above shows, the keywords are split by the spaces in between each word, and each of these words are stored in a String array tagKeywords.

The array of keywords is then passed into the parser’s private method, getImprovedList(), to retrieve a more comprehensive list of tags in addition to the original list of keywords.

ℹ️	The details of getImprovedList are not crucially important to the functionality of the parser, and is thus omitted here, but included in the addendum in Section 3.3.6.

After obtaining the improved list, the parser constructs the command Predicate (details in Section 3.3.4), and the Command itself (details in the Section 3.3.5). Then it returns the Command to AddressbookParser and then the LogicManager for execution.

3.3.4. Implementation of Predicate

The Predicate associated with this functionality is called PersonContainsTagsPredicate, found in seedu.address.model.person.

This Predicate has three attributes, keywords, which are generated in the parser, and 2 lists, keywordsToInclude and keywordsToExclude. The 2 lists are generated from keywords.

After this Predicate is constructed, it is used in the constructor of a FindPersonsWithTagsCommand and becomes that command’s attribute.

When the command is executed, this Predicate will be called for every contact in the address book to determine if a contact should be filtered or not based on the user’s inputs.

To do so, the test method of this Predicate is used, which returns a Boolean value: true if this contact should be returned, and false otherwise.

Within this test method, the following steps occur, for each contact in the currently stored in the application:

Figure 3.3.4.1 : Findtags Predicate Activity Diagram

As seem from Figure 3.3.4.1, firstly, all of the person’s tags, if any, are appended to a String allTagNames. For example, if a contact has tags "friends" and "colleagues", the resulting String is "friends colleagues".

Then, the comparison is made between allTagNames and the 2 lists generated in constructor, to return the appropriate Boolean value. Below is the code snippet used in the comparison. Note that this is not the only way to implement this comparison.

Code Snippet:

//For scenario 2
if (onlyKeywordsToExcludeAreSpecified) {
            return !(keywordsToExclude.stream()
                    .anyMatch((keyword -> StringUtil.containsWordIgnoreCase(allTagNames, keyword))));
}


//For scenarios 1 and 3
return keywordsToInclude.stream()
    .anyMatch(keyword -> StringUtil.containsWordIgnoreCase(allTagNames, keyword)) &&
    !(keywordsToExclude.stream()
    .anyMatch((keyword -> StringUtil.containsWordIgnoreCase(allTagNames, keyword))));

3.3.5. Implementation of Command

The command executed in this feature is FindPersonsWithTagsCommand, found in seedu.address.logic.commands.

After the command parser returns the command to AddressbookParser and then to the LogicManager, assuming that no exceptions are thrown so far, the command is executed, by calling its execute() method.

In this execute() method, the current model invokes its updateFilteredPersonList method, with the command Predicate as described above as its parameter.

This runs the test() method of the Predicate, which determines the appropriate contacts to filter. This causes the model to update accordingly and filters the contacts displayed in the UI.

Finally, this command returns a CommandResult, which includes the number of contacts being displayed. This value is displayed on the UI command box for the user’s reference.

3.3.6. Addendum

Implementation of getImprovedList
In the command parser (as detailed in Section 3.3.3), there exists a private method getImprovedList(), which takes in the list of keywords entered by the user and attempts to return a more comprehensive one in addition to the original list, to account for grammatical differences in plural and singular forms of the keywords.

To give an example, if the keyword is “friend”, the extra keyword generated is “friends” and vice-versa. This works for “exclusion-keywords” (keywords with a dash in front) as well.

What is of note is that this method is merely a crude, quality-of-life improvement for the user. It simply generates the keywords by appending the letter ‘s’ to keywords which do not end with ‘s’, and removes ‘s’ from words that do end with the letter ‘s’.

As a result, it does not account for words where singular and plural forms differ by more than just a single letter ‘s’, such as “family” and “families”.

It is therefore recommended that future developers improve this method, perhaps by implementing a proper dictionary or library for this method, after weighing the costs and benefits. Alternatively, this idea could be further improved or refined on with a Lookup Table to save file storage space.

Nevertheless, this improvement is meant to increase user enjoyment and convenience. The onus of organising and spelling tags in an organised manner is still on the user. To that end, if the case arises that, based on user feedback, this improvement does more harm than good, it is recommended that this feature be removed or made optional. However, this is not something that the current developers foresee will occur based on observation of how people in general spell their tags.

3.3.7. Design Considerations

Aspect: Improving list of keywords.

Alternative 1 (current choice): Add 's' to letters that do not end with 's', and vice-versa.
Pros: Easy to implement and read.
Cons: Does not account for all words in English, may have non-English words.

Alternative 2: Import appropriate library for getting singular/plural words.
Pros: More likely to account for all words.
Cons: May impact performance.

Alternative 3: Implement a Look-up Table.
Pros: Can account for more words than alternative 1, and less impact on performance and storage than alternative 2.
Cons: Might be difficult to implement and may not be as comprehensive as alternative 2.

Aspect: Comparision of tag names and keywords in predicate.

Alternative 1 (current choice): Append names to an empty String for comparision with keywords.
Pros: Easy to implement and change.
Cons: Requires use of lambda, which may be more difficult to understand for beginners.

Alternative 2: Compare tag against tag by encapsulating all keywords into Tags.
Pros: Can use the equals specified in Tag, and/or comparator instead of lambda for better readability.
Cons: More difficult to implement, and may create many tags that are never used because the keywords and expanded to improve user convenience (singular vs plural tag names).

3.4. Birthdays

Users are able to store birthdays of their contacts by inputting in the format of ddMMyyyy when adding a person, using the prefix b/.

In general, the ability to store a person’s birthday was implemented by adding it to the component of Person.

3.5. Representation of birthdays

Storing of birthdays is facilitated by an immutable Birthday object, which is a component of Person.

The main classes that implement this attribute is: AddCommand, AddCommandParser, EditCommand, EditCommandParser, Person, PersonListCard.

However, birthday has been made to be an optional field to include while adding a new contact.

3.6. Validation of birthday

Birthday uses the DateFormat and the SimpleDateFormat packages to check if the birthday entered is a valid date. For example, 31/02/1998 is not a valid date.

Validation of birthday is implemented this way:

---
public static boolean isValidBirthday(String test) {
    if (test.matches(BIRTHDAY_VALIDATION_REGEX)) {
        try {
            DateFormat df = new SimpleDateFormat(DATE_FORMAT);
            df.setLenient(false);
            df.parse(test);
            return true;
        } catch (ParseException pe) {
            return false;
        }
    } else if (test.matches("")) {
        return true;
    }
    return false;
}
---

3.6.1. Design Considerations

Aspect: Representation of birthdays
Alternative 1 (current choice): Display the birthday of the specified contact after the address of the contact
Pros: It follows the format of the person card
Cons: It is difficult to recognise the number displayed is the birthday as it is merely represented as an eight digit number

Alternative 2: Display the birthday with "Birthday:" in front
Pros: Simple and easy to understand
Cons: Inconsistent with the format in person card

3.7. Implementation of List Tags

The application allows users to see the list of all tags that are currently attached to contacts in the application. The command word is listtags, and the shortcut alternative is lt. The follow subsections explain how the program is supposed to function given the command, and how it is implemented.

3.7.1. User Inputs and Expected Actions/Results

In general, when this command is used, there are only 2 scenarios that will occur.

Scenario 1
There is at least 1 tag attached to at least 1 contact.

In this scenario, the application will show these tags in the result box.

Below is the format of the results:
You have the following tags: [tag1] [tag2] [tag3] …

Scenario 2
There are no tags attached to any contacts in the application. This could happen if there are:
1. No contacts in the application.
2. No tags attached to any contact.

In this scenario, the application will show to user the following message:
"You do not have any tags!"

3.7.2. Brief Overview of the Command

A brief overview of the steps taken by the application in producing the appropriate results is as given:
1. Creates a list of tags by iterating through every Contact in the application and adding their tags to the list.
2. Check if this list of tags is empty or not, that is, whether it is scenario 1 or scenario 2.
2a. If it is scenario 2, that is, there are no tags to output, the command merely returns the failure message.
3. If the list is not empty, it will output the success message along with the list of tags in the appropriate format. The details of this step is given in the next subsection.

3.7.3. Implementation of Success Scenario

The steps taken are:
1. Converts the list of Tags to a list of String containing the names of each Tag.
2. Sorts the list in alphabetical order.
3. Using a StringBuilder, appends the names to each other with the appropriate formatting.
4. Output the result.

3.7.4. Design Considerations

Aspect: Order of Tags displayed
Alternative 1 (current choice): Display in alphabetical order.
Pros: More readable and more easily understood.
Cons: May not be the most meaningful.

Alternative 2: Display based on how many of each tag there are, for example in ascending order.
Pros: Might be more meaningful for certain users and cases.
Cons: Much more difficult to implement, and may appear more confusing to users, as alphabetical order is generally more easily understood.

Alternative 3: Allow option to display both in alphabetical order or in ascending order.
Pros: Best of both worlds, allowing user to choose the most meaningful.
Cons: Adding on to the already numerous commands may not be the most meaningful, especially when the main function of this enhancement is to complement the find tags feature.

3.8. Implementation of Facebook Field

Each contact can now support a Facebook field, which is displayed on the person card.

A few things to note about this field:

The Facebook field is not compulsory when adding to the application.
If user does not input the Facebook field, removes it using the edit command, it will be replaced by the default Facebook homepage, "https://facebook.com/".
User can input Facebook field in 2 ways, the first is the entire link to the Facebook profile. In this case, the program should take the entire link and store it as the Facebook field of the user.
If the user enters in the Facebook field a String that is not a link, the programe should assume that what was entered was instead the profile name or profile number of the contact, and thus append the Facebook link prefix to it.
For example, if user enters f/john for a contact, john’s Facebook field would be "https://facebook.com/john/".

To perform steps 3 and 4, the program checks if that is entered in the field is a valid URL. If it is, then assume it is 3. and store the entire URL as the Facebook field. Else, append and store that String as the Facebook field, which is 4.

In future update, will allow select command to open the facebook field instead of google searching the contact’s name.

3.8.1. Design Considerations

Aspect: Empty or non-valid URL Facebook fields
Alternative 1 (current choice): Turn it into a proper URL by appending the correct prefixes.
Pros: More readable on the Person Card, user can easily see if there is a mistake.
Cons: May create some strange links.
Alternative 2: Leave it as it is.
Pros: Simple to implement.
Cons: Will look strange and ambiguous on the Person Card, especially if user made a mistake and does not notice.

3.9. 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:

3.9.1. 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.

3.10. Task class mechanism

The Task class, which is located inside Model, is implemented with similar logic as Person class. We have introduced three commands that modifies the address book: addt, editt and deletet, which extends UndoableCommand. A Task consist of three sub-components: Header, Desc and Deadline. Commands such as undo and redo can be used to alter events in the list as they deal with code that directly modifies the address book.

The TaskPanel is incorporated into the address book MainWindow to display all the tasks inside the internal list using ObservableList<ReadOnlyTask>. This process will be explained later on under the section Task card.

3.10.1. Task methods

As mentioned earlier, the Task class contains three main methods: addt, editt and deletet. The execution flow is similar for all three methods on a higher level.

3.10.2. Exceptions

When the user input a task command with its parameters, the validity of the command word is checked inside the AddressBookParser. Next, the presence of the parameter prefixes is checked inside AddTaskCommandParser. An appropriate ParseException will be thrown if the command word or prefixes are incorrect.

Before modifying the list of tasks inside the address book, the system may throw exceptions due to some invalid parameters. Here are the possible exceptions:

TaskNotFoundException: This exception can be thrown by editt and deletet command when the an invalid index for a task is provided by the user. The index needs to be within the size of the task list at the current state of the address book.
DuplicateTaskException: This exception can be thrown by addt and editt command. The system will first create an Task object with the input parameters, compare the object to all tasks residing in the task list and throw this exception if there is a duplicate found.

Editing of task is implemented this way:

    ReadOnlyTask taskToEdit = lastShownList.get(index.getZeroBased());
    Task editedTask = createEditedTask(taskToEdit, editTaskDescriptor);

    try {
        model.updateTask(taskToEdit, editedTask);
    } catch (DuplicateTaskException dee) {
        throw new CommandException(MESSAGE_DUPLICATE_TASK);
    } catch (TaskNotFoundException enfe) {
        throw new AssertionError("The target task cannot be missing");
    }
    model.updateFilteredTaskList(PREDICATE_SHOW_ALL_TASKS);
    return new CommandResult(String.format(MESSAGE_EDIT_TASK_SUCCESS, editedTask));

3.10.3. Task card

The TaskCard class extends UiPart<Region> to represent a distinct part of the UI. The object properties of every task is assigned to a label held by an TaskCard. The graphic scene is then constructed with the appropriate FXML files created to support the display of all tasks.

Design implementation

When the user starts the MainApp, the system calls the UiManager to create a new MainWindow and fills it with TaskListPanel and other components. The displayed events are created by UniqueTaskList and the binding of individual UI elements to the TaskCard ensures that any changes to the parameter will be displayed in the TaskListPanel. The sequence diagram below illustrates the interaction between the TaskCard and the UiManager:

3.10.4. Design Considerations

Aspect(future enhancement): How to implement adding/tagging of contacts into a Task using a Person list parameter

Chosen Implementation:
Add by the index of contact shown in the PersonListPanel.
Pros:
The system only has to check for validity of index which leads to increased performance.
Cons:
This requires the user to refer to the PersonListPanel before executing command to add contact into task’s Person list.

Alternative: Add by the name of contact in the Person list.
Pros:
Easier for users to add using names, as they do not need to refer to the Person list.
Cons:
System has to check through the list to check if the contact’s name exist in the current address book, which can be more difficult if there are more than one contacts with the same name.

3.11. Send email mechanism

The send email mechanism is facilitated by a specific Google account, which the user needs to login to before he can begin using the application to send e-mails. He can then use the command-line interface of the application to add the recipient, subject and body of the e-mail.

E-mails can be sent to the e-mail address attached to any contact in the address book.

Sending of e-mails is implemented this way:

public CommandResult execute() throws CommandException, GoogleAuthException {
    requireNonNull(model);
    List<ReadOnlyPerson> lastShownList = model.getFilteredPersonList();

    if (targetIndex.getZeroBased() >= lastShownList.size()) {
        throw new CommandException(Messages.MESSAGE_INVALID_PERSON_DISPLAYED_INDEX);
    }

    String personToSendEmail = lastShownList.get(targetIndex.getZeroBased()).getEmail().toString();

    try {
        MimeMessage emailToBeSent = ModelManager.createEmail(personToSendEmail,
                EMAIL_SENDER, emailSubject, emailBody);
        Gmail gmailService = new GetGmailService().getGmailService();
        message = ModelManager.sendMessage(gmailService, EMAIL_SENDER, emailToBeSent);
    } catch (MessagingException | IOException E) {
        assert false;
    }

    return new CommandResult(String.format(MESSAGE_SUCCESS));
}

ℹ️	Users must login using your e-mail and password to a specific Google account before they can start using this feature. If login is unsuccessful, they will be prompted to login again.

ℹ️	Requested access by Google must be provided before any e-mails can be sent.

ℹ️	Internet connectivity is needed for this feature as the application does not store any e-mail drafts.

ℹ️	Send e-mail feature must be used immediately after login as the application does not store any user data. Hence after login is successful, it is not possible to use other commands and then use the send e-mail command.

3.11.1. Design Considerations

Aspect: Implementation of send e-mail
Alternative 1: Save login details to allow more flexibilty.`
Pros: Easier access to command as users can execute other commands in between login and sending e-mails.
Cons: Security concerns raised as user data is saved within the application.
Alternative 2 (current choice): Only allow users to use send command immediately after login.`
Pros: Safe option as no user details are stored even when the command is used repeatedly.
Cons: Not user-friendly as it forces users to use features of the application in a certain order.

3.12. 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

3.13. 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 can…
`* * *`	new user	see usage instructions	refer to instructions when I forget how to use the App
`* * *`	new user	import existing contacts	add contacts quickly when starting to use the App or reinstalling the App
`* * *`	frequent user	backup existing contacts as I add/remove them	restore a previous version of my contacts if I make a big mistake
`* * *`	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	sort persons by arrange the names in my contacts by Alphabetical order	locate a person easily
`* * *`	forgetful user	have prompts for right command syntax when I enter the wrong one	use the app more conveniently
`* * *`	user	arrange the names in my contacts according to first name	locate a person easily
`* * *`	user	arrange the names in my contacts according to last name	locate a person easily
`* * *`	user	favourite a contact	have favorites appear at the top of search results
`* * *`	user	update information for any of my contacts	not have to delete and add a contact just to change his details
`* * *`	user	share a contact with other people
`* *`	user	hide private contact details by default	minimize chance of someone else seeing them by accident
`* *`	forgetful user	view my contacts' profile picture(s)	have a picture to attach to the contact
`* *`	user	alternate between using the alias and the name of my contacts	have a nickname to attach to the person
`* *`	user	view frequently contacted/searched for people at the top of the list
`* *`	lazy user	delete multiple users at a time
`* *`	power user	call a selected contact within 1 command after selecting the contact
`* *`	power user	message a selected contact within 1 command after selecting the contact
`* *`	power user	attach multiple notes to each contact
`* *`	user with many contacts	notified when I have 2 contacts with the same name to add an alias or tag	do not get confused by 2 contacts with the same name
`* *`	user with many contacts	add multiple tags to each contact	easily group them
`* *`	user	search results to be displayed and updated every time i key in an alphabet	search for contacts without having to finish typing in the whole name
`*`	user	arrange the names in my contacts according to their address in alphabetical order	locate a person easily
`*`	user	view the number of contacts that I have
`*`	user	merge contacts
`*`	user	select relevant information and export to a list
`*`	user	access to more buttons	have more convenience using the App
`*`	user	see the address of a selected contact on Google Maps within 1 command
`*`	user	link my contacts to their social media account
`*`	user with many contacts	have tabs for different category of contacts	easily see who is in which group
`*`	user	customize the background colour of the application	personalize the App.

{More to be added}

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.

{More to be added}

Use case: Sort contacts alphabetically

MSS

User requests to sort contacts alphabetically
AddressBook sorts contacts alphabetically according to their names
AddressBook shows contact list to user

Use case ends.

Extensions

1a. The list is empty.
- 1a1. AddressBook shows “empty list of contacts” to user
  
  Use case ends.

Use case: Adding a tag to a person

MSS

User requests to list persons
AddressBook shows list of persons
User requests to add a specific tag to a person in the list
AddressBook confirms the details of the instruction with the user
User confirms command
AddressBook adds tag to this person

Use case ends

Extensions

1a. The list is empty.
- 1a1. AddressBook shows “empty list of contacts” to user
  
  Use case ends.

3a. User enters an invalid person on the list (out of bound of list)
- 3a1. AddressBook shows “invalid person, choose correct person (starting index to ending index)” and displays list again in background
  
  Use case resumes at step 3.

3b. User enters unsupported character for tag
- 3b1. AddressBook shows “invalid tag name, only valid characters (display valid characters)”.
  
  Use case resumes at step 3.

4a. User cancels command
- 4a1. AddressBook shows “command cancelled”.
  
  Use case ends.

Use case: finding by tags

MSS

User requests to find contacts with a certain tag name
App displays all contacts with such tags

Use case ends

Use case: displaying list of tags

MSS

User reuqests to list all tags
App displays all existing tags

Use case ends

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.
Any command should not take longer than 1 second to execute
App should be able to hold at least 5000 contacts
Should support integration with Google contacts
Should support integration with Google Map for proximity services
App should support importing and exporting of contacts in Microsoft Excel Format
Support multiple instances of the app on a single device
Support integration with telecommunication apps such as, but not limited to, WhatsApp, Line etc.
Support integration with social media services and apps

{More to be added}

Appendix E: Glossary

Mainstream OS

Windows, Linux, Unix, OS-X

Private contact detail

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

Files

DeveloperGuide.adoc

Latest commit

History

DeveloperGuide.adoc

File metadata and controls

AddressBook Level 4 - 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. Google Implementation

3.1.1. GoogleContactsBuilder class and GoogleID attribute

3.1.2. Import Command

3.1.3. Export Command

3.1.4. Sync Command

3.1.5. Design Considerations

3.2. EasyFind mechanism

3.2.1. Design Considerations

3.3. Finding Contacts by Tags

3.3.1. User Inputs and Expected Actions/Results

3.3.2. Brief Overview of Command Procedure

Class Diagram:

Activity Diagram:

Sequence Diagram:

3.3.3. Implementation of Parser

3.3.4. Implementation of Predicate

3.3.5. Implementation of Command

3.3.6. Addendum

3.3.7. Design Considerations

3.4. Birthdays

3.5. Representation of birthdays

3.6. Validation of birthday

3.6.1. Design Considerations

3.7. Implementation of List Tags

3.7.1. User Inputs and Expected Actions/Results

3.7.2. Brief Overview of the Command

3.7.3. Implementation of Success Scenario

3.7.4. Design Considerations

3.8. Implementation of Facebook Field

3.8.1. Design Considerations

3.9. Undo/Redo mechanism

3.9.1. Design Considerations

3.10. Task class mechanism

3.10.1. Task methods

3.10.2. Exceptions

3.10.3. Task card

Design implementation

3.10.4. Design Considerations

3.11. Send email mechanism

3.11.1. Design Considerations

3.12. Logging

3.13. 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

`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