Developer Guide

Introduction

PeopleSoft is a desktop app for calculating the salary for shift-based contractors, optimized for use via a Command Line Interface (CLI). If you are a HR manager and you can type fast, PeopleSoft can get your payroll tasks done much faster than traditional GUI apps.

PeopleSoft helps to:

• Simplify the management of data
• Reduce menial labour
• Reduce mistakes due to human error in calculation / accidental edits
• Help employees be assured that their hours and pay are registered correctly in the system

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• Introduction
• Acknowledgements
• Setting up, getting started
• Design
  • Architecture
  • UI component
  • Logic component
  • Model component
  • Storage component
  • Common classes
• Implementation
  • JSON serialization and deserialization
  • The Find command
    • The PersonContainsKeywordPredicate class
  • The JobList interface and UniqueJobList class
  • The Job class
  • The Job and Person association - Employment
    • Design considerations:
  • [Proposed] Addition of pay multipliers to Job
    • Design considerations:
  • [Proposed] Undo/redo feature
    • Proposed Implementation
    • Design considerations:
  • [Proposed] Data archiving
• Documentation, logging, testing, configuration, dev-ops
• Appendix: Requirements
  • Product scope
  • User stories
  • Use cases
  • Non-Functional Requirements
  • Glossary
• Appendix: Instructions for manual testing
  • Launch and shutdown
  • Adding an employee
  • Deleting an employee

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Acknowledgements

• Project adapted from addressbook-level3
• Layout of user stories adapted from TAB
• {list here sources of all reused/adapted ideas, code, documentation, and third-party libraries – include links to the original source as well}

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Setting up, getting started

Refer to the guide Setting up and getting started.

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Design

Architecture

Figure 1. Architecture diagram of the high-level design of PeopleSoft

Given below is a quick overview of main components and how they interact with each other.

Main components of the architecture

Main has two classes called Main and MainApp. It is responsible for,

• At app launch: Initializing the components in the correct sequence, and connecting them up with each other.
• At shut down: Shutting down the components and invoking cleanup methods where necessary.

Commons represents a collection of classes used by multiple other components.

The rest of the application 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.

How the architecture components interact with each other

Figure 2. Sequence diagram showing component interactions when the user enters the command persondelete 1

Each of the four main components (also shown in the diagram above),

• defines its API in an interface with the same name as the component.
• implements its functionality using a concrete {Component Name}Manager class (which follows the corresponding API interface mentioned in the previous point).

For example, the Logic component defines its API in the Logic.java interface and implements its functionality using the LogicManager.java class which follows the Logic interface. Other components interact with a given component through its interface rather than the concrete class (reason: to prevent outside component’s being coupled to the implementation of a component), as illustrated in the (partial) class diagram below.

Figure 3. Partial class diagram of the interaction of components

The sections below give more details of each component.

UI component

The API of this component is specified in the Ui.java interface.

Figure 4. Class diagram of GUI

The UI consists of a MainWindow that is made up of parts e.g.SideBar, CommandBox, ResultDisplay, OverviewPage, etc. All these, including the MainWindow, inherit from the abstract UiPart class which captures the commonalities between classes that represent parts of the visible GUI.

The UI component uses the JavaFx UI framework. The layout of these UI parts are defined in matching .fxml files that are in the src/main/resources/view folder. For example, the layout of the MainWindow is specified in MainWindow.fxml

The UI component,

• executes user commands using the Logic component.
• listens for changes to Model data so that the UI can be updated with the modified data.
• keeps a reference to the Logic component, because the UI relies on the Logic to execute commands.
• depends on some classes in the Model component, as it displays the Person and Job objects residing in the Model.

Logic component

The API of this component is specified in the Logic.java interface.

Here’s a (partial) class diagram of the Logic component:

Figure 5. Partial class diagram of the Logic component

How the Logic component works:

1. When Logic is called upon to execute a command, it uses the AddressBookParser class to parse the user command.
2. This results in a Command object (more precisely, an object of one of its subclasses e.g., JobAddCommand) which is executed by the LogicManager.
3. The command can communicate with the Model when it is executed (e.g. to add a person).
4. The result of the command execution is encapsulated as a CommandResult object which is returned back from Logic.

Figure 6. Sequence diagram of the interactions within the Logic component for the execute("delete 1") API call

Here are the other classes in Logic (omitted from the class diagram above) that are used for parsing a user command:

Figure 7. Class diagram of the Parser component, a subcomponent of the Logic component

How the parsing works:

• When called upon to parse a user command, the AddressBookParser class creates an XYZCommandParser (XYZ is a placeholder for the specific command name e.g., JobAddCommandParser) which uses the other classes shown above to parse the user command and create a XYZCommand object (e.g., JobAddCommand) which the AddressBookParser returns back as a Command object.
• All XYZCommandParser classes (e.g., JobAddCommandParser, JobDeleteCommandParser, …) inherit from the Parser interface so that they can be treated similarly where possible e.g, during testing.

Model component

The API of this component is specified in the Model.java interface.

Figure 8. Class diagram of the Model component

The Model component,

• stores the address book data - i.e. all Person objects (which are contained in a UniquePersonList object), all Job objects (which are contained in a UniqueJobList object), and auxiliary classes Employment, PaymentHandler etc.
• allows for the automatic serialization and deserialization of AddressBook objects (and any component objects, e.g. Person, Email, etc) to and from JSON.
• stores the currently ‘selected’ Person objects (e.g., results of a search query) as a separate filtered list which is exposed to outsiders as an unmodifiable ObservableList<Person> that can be ‘observed’ e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
• stores the currently ‘selected’ Job objects (e.g., results of a search query) as a separate filtered list which is exposed to outsiders as an unmodifiable ObservableList<Job> that can be ‘observed’ e.g. the UI can be bound to this list so that the UI automatically updates when the data in the list change.
• stores a UserPref object that represents the user’s preferences. This is exposed to the outside as a ReadOnlyUserPref objects.
• contains an Employment class which represents the associations between Person and Job objects.
• does not depend on any of the other three components (as the Model represents data entities of the domain, they should make sense on their own without depending on other components)

A more detailed model of Person and Job is given below. Notice the association class Employment between Person and Job.

Figure 9. Class diagram of Person and Job

Storage component

The API of this component is specified in the Storage.java

Figure 10. Class diagram of the Storage component

The Storage component,

• can save both address book data and user preference data in JSON format, and read them back into corresponding objects.
• inherits from both AddressBookStorage and UserPrefStorage, which means it can be treated as either one (if only the functionality of only one is needed).
• depends on some classes in the Model component (because the Storage component’s job is to save/retrieve objects that belong to the Model)

Common classes

Classes used by multiple components are in the peoplesoft.commons package.

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Implementation

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

JSON serialization and deserialization

The serialization and deserialization of model objects (e.g. AddressBook, UniquePersonList, Person, Job, Tag) is handled by custom serializers and deserializers, implemented as nested class within each model class.

These serializers and deserializers are automatically used by Jackson during serialization and deserialization.

The serializer and deserializer for each class determine how the objects are to be serialized and deserialized, including but not limited to:

• which fields are to be stored,
• how each field should be (de)serialized, e.g. by directly converting it to/from a JSON type, or by delegating it to Jackson (which will use the serializer/deserializer for the field type), and
• how the fields and current object are to be represented as (or parsed from) JSON values, e.g. objects, strings, numbers.

This architecture has some advantages:

• The serdes implementations are kept together with the related classes; developers adding new model classes will not have to modify files in other packages.
  • The previous implementation (with JsonAdaptedPerson etc.) requires that developers update the JsonAdapted classes belonging in the Storage component; this may not be immediately evident to developers.
• Developers adding new model classes can incorporate existing types (that already have corresponding serializers/deserializers) without needing to duplicate the serdes code, unlike with the previous implementation.
• Developers will also not need to (practically) duplicate classes, e.g. Job -> JsonAdaptedJob (with the @JsonCreator annotation), just so that Jackson has something to serialize from/deserialize to.

However, it also has some drawbacks:

• It can be rather verbose, since each serializer/deserializer class contains a portion of boilerplate code
• Developers writing serializers/deserializers will need to have basic knowledge of JSON, e.g. the types that are available, the structure of JSON objects and arrays, etc
• Some knowledge of Jackson components (e.g. JsonParser, JsonGenerator, ObjectNode) is also required, as developers will need to use them to write values to/read values from the internal Jackson representation of a JSON value/object.

The Find command

The Find command is an enhancement of the Find feature provided in AB3. It is structured using an object of PersonContainsKeywordPredicate, adapted from NameContainsKeywordPredicate. It has the following attributes:

• static final String COMMAND_WORD initialised to 'find'
• static final String MESSAGE_USAGE initialised to the relevant message.
• PersonContainsKeywordPredicate predicate used to find Person objects that match with the given keyword.

Applying this filter to the entire list means that only Persons that match ALL the keywords would be retained in the filtered list.

The PersonContainsKeywordPredicate class

The match itself is defined as follows (within the PersonContainsKeywordPredicate class which implements the Predicate interface): If a Person contains ALL the keywords passed in the query, either in their name field or as equivalent to an element in their tags set of Tag objects, then, passed as a parameter to test(), it is a valid match.

The implementation is achieved through using stream manipulations to iterate through each person object, and for any such object, iterating through each keyword passed in the query. The keyword is then checked if it is contained within the name or among the tags.

One motivation behind using streams rather than iteration was that streams can be better optimized, given the need or bandwith arising later.

The JobList interface and UniqueJobList class

The JobList is an interface for the list of jobs, that implements the Iterable interface and supports minimal list operations.

The UniqueJobList class implements the JobList interface to that enforces uniqueness between its elements and does not allow nulls. Furthermore, it has the following attributes, to interact with java.fx effectively.

• ObservableList<Job> internalList
• ObservableList<Job> internalUnmodifiableList

The Job class

The Job class is an abstraction for a job stored in PeopleSoft. A Job object is immutable and contains the following attributes:

• String jobId - Jobs are referenced by this attribute.
• String desc - A user-readable description of this job.
• Duration duration - The duration that a job has been worked. Is used together with rate to calculate the total job earnings. Uses java.time.Duration.
• boolean hasPaid - A boolean to denote if this job is completed. Used to calculate the salary of a Person.
• boolean isFinal - A boolean to denote if this job has finalized payments.

The use of immutability ensures that there are no unintended side effects of modifying a Job. Whenever a Job needs to be modified (for example setting the value of hasPaid), a new immutable copy of the Job with the desired changes is created to replace the old instance. Two Job objects are considered the same job if they share the same jobId, which can be compared using Job#isSameJob().

The Job and Person association - Employment

In order to represent how a job may be assigned to a person (or a person may take on a job) in real life, an association class Employment is used. The class handles the following responsibilities:

• Assigning a Job to a Person.
• Removing all necessary associations on the deletion/edit of a Job or Person.
• Filtering the Job objects that are mapped to a Person.

In the current implementation, there is a many-to-many mapping of Job objects to Person objects. An association can be created using Employment#associate(job, person). The jobs are internally referenced by jobId, while the persons are referenced by personId. Currently, the class Employment is written as a singleton. This may be changed to be a field of AddressBook due to potential obstacles with the testing of the serialization/deserialization of the class.

Design considerations:

Aspect: How the relational mapping between Job and Person is stored:

• Alternative 1 (current choice): Saves the mapping of Job objects to Person objects in Employment.
  • Pros: Guarantee of commutative association.
  • Cons: Harder to implement.
• Alternative 2 (rejected): Saves a map of the ids of related Person objects in Job objects, and a map of the ids of related Job objects in Person objects.
  • Pros: Easier to implement.
  • Cons: Mutual associations are not guaranteed. The possible extension of a one-to-many relationship between Person and Tag would be harder to implement.

[Proposed] Addition of pay multipliers to Job

The proposed mechanism for adding pay multipliers to Job is facilitated by MultiplierTag. MultiplierTag extends Tag with a multiplier addition timeline history, stored internally as a MultiplierHistory Map between pay multiplier values and their time of addition.

The inclusion of MultiplierTag in calculating pay Job objects is facilitated by PaymentHandler#createPendingPayments which calls on the modified operation Job#calculatePay(Set<Tags>). Job#calculatePay(Set<Tags>) returns the appropriately scaled pay amount after accounting for every tag the passed Person parameter has. Job#calculatePay() is called by calls Job#calculatePay() based on optional Tag parameters.

Design considerations:

• Alternative 1 (current choice): Saves a Map of previous multipliers and time of addition in Tag.
  • Pros: Easy to implement. Pay breakdown can be useful in the implementation of other features.
  • Cons: May have performance issues in terms of memory usage.
• Alternative 2: Saves pay amount as a fixed value and updates it when Tag is edited.
  • Pros: Will use less memory as only one value is being stored.
  • Cons: Loss of useful pay breakdown information.

[Proposed] Undo/redo feature

Proposed Implementation

The proposed undo/redo mechanism is facilitated by VersionedAddressBook. It extends AddressBook with an undo/redo history, stored internally as an addressBookStateList and currentStatePointer. Additionally, it implements the following operations:

• VersionedAddressBook#commit() — Saves the current address book state in its history.
• VersionedAddressBook#undo() — Restores the previous address book state from its history.
• VersionedAddressBook#redo() — Restores a previously undone address book state from its history.

These operations are exposed in the Model interface as Model#commitAddressBook(), Model#undoAddressBook() and Model#redoAddressBook() respectively.

Given below is an example usage scenario and how the undo/redo mechanism behaves at each step.

Step 1. The user launches the application for the first time. The VersionedAddressBook will be initialized with the initial address book state, and the currentStatePointer pointing to that single address book state.

Step 2. The user executes delete 5 command to delete the 5th person in the address book. The delete command calls Model#commitAddressBook(), causing the modified state of the address book after the delete 5 command executes to be saved in the addressBookStateList, and the currentStatePointer is shifted to the newly inserted address book state.

Step 3. The user executes add n/David …​ to add a new person. The add command also calls Model#commitAddressBook(), causing another modified address book state to be saved into the addressBookStateList.

Step 4. The user now decides that adding the person was a mistake, and decides to undo that action by executing the undo command. The undo command will call Model#undoAddressBook(), which will shift the currentStatePointer once to the left, pointing it to the previous address book state, and restores the address book to that state.

The following sequence diagram shows how the undo operation works:

The redo command does the opposite — it calls Model#redoAddressBook(), which shifts the currentStatePointer once to the right, pointing to the previously undone state, and restores the address book to that state.

Step 5. The user then decides to execute the command list. Commands that do not modify the address book, such as list, will usually not call Model#commitAddressBook(), Model#undoAddressBook() or Model#redoAddressBook(). Thus, the addressBookStateList remains unchanged.

Step 6. The user executes clear, which calls Model#commitAddressBook(). Since the currentStatePointer is not pointing at the end of the addressBookStateList, all address book states after the currentStatePointer will be purged. Reason: It no longer makes sense to redo the add n/David …​ command. This is the behavior that most modern desktop applications follow.

The following activity diagram summarizes what happens when a user executes a new command:

Design considerations:

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.

{more aspects and alternatives to be added}

[Proposed] Data archiving

A simple archival feature can be easily implemented, as all of the app data can be (and is currently) stored in a single file.

As such, it should be trivial to add an archive command, which saves a copy of the database to a different filename. Auto-archival should also be possible, e.g. by saving a copy of the database on every X changes, or if the last archive was made more than Y hours ago.

The archived data files may not be as user-friendly though – restoring data archives will require users to copy an archived copy of the database to the expected location, then restarting the application.

We might hence want to implement a rudimentary interface with which users can browse through older archives – this interface might show basic information about each archive, such as:

• date of archive
• number of employees/jobs
• size of archive

…as well as provide an easy way to load the archive into the app temporarily, which can be implemented as follows:

1. save the current database somewhere
2. make a copy of the archive
3. set the storage filename to point to the archive copy
4. reload the application, if required

If the user desires to return to the original database, then we can simply load the database saved in Step 1 and reload the application.

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Documentation, logging, testing, configuration, dev-ops

• Documentation guide
• Testing guide
• Logging guide
• Configuration guide
• DevOps guide

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Appendix: Requirements

Product scope

Target user profile: HR Managers of companies offering contractor services

• have a need to manage a significant number of employees and jobs
• employee pay is calculated based on hours worked
• prefer desktop apps over other types
• can type fast
• prefer typing to mouse interactions
• are reasonably comfortable using CLI apps

Value proposition:

• Simplify the management of data
• Reduce menial labour
• Reduce mistakes due to human error in calculation / accidental edits
• Helps employees be assured that their hours and pay are registered correctly in the system

User stories

For convenience, our user stories have been categorized with three broad labels:

1. [E] - Employee-related functions
2. [J] - Job-related functions
3. [N] - Neither of the above

Note: multiple labels can be applied to a single user story.

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

Label	Priority	As a …​	I want to …​	So that I can…​
N	* *	new user	see usage instructions	refer to instructions when I forget how to use the App
N	* *	potential user	see the app populated with sample data	easily see how the app will look like when it is in use
N	* *	HR Manager	log into separate modes for HR-related functions and for job-related functions	easily access relevant data for the type of work I am doing at any given time
N	* * *	HR Manager	load and save data in human-readable data files	I can backup the data externally or access it in a different application
N	* * *	HR Manager	exit the application
E	* * *	HR Manager	add a new employee
E	* * *	HR Manager	add tags to employees	identify their roles
E	* * *	HR Manager	edit an employee’s information	rectify mistakes or update their personal information if need be
E	* * *	HR Manager	delete an employee
E	* * *	HR Manager	delete all employees	mass-remove entries that I no longer need
E	* * *	HR Manager	list all employees
E	* * *	HR Manager	find an employee by name or tag	locate details of employees without having to go through the entire list
J	* * *	HR Manager	add a new job
J	* * *	HR Manager	mark a job as having been paid for
J	* * *	HR Manager	mark a job as having been completed
J	* * *	HR Manager	update a job
J	* * *	HR Manager	delete a job
J	* * *	HR Manager	delete all jobs	mass-remove entries that I no longer need
J	* * *	HR Manager	find a job by description	locate details of jobs without having to go through the entire list
EJ	* * *	HR Manager	assign an employee to a job
EJ	* * *	HR Manager	view the salary owed to a given employee	pay them
EJ	* * *	HR Manager	pay for a given type of job
EJ	* * *	HR Manager	see which jobs each employee is working on	pay them accordingly
EJ	* *	HR Manager	edit pay multiplier factors (e.g. overtime, experience, emergency on-calls)	apply changes in payment policies across the organization

Use cases

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

Use case: Delete an employee

MSS

1. User requests to list employees
2. PeopleSoft shows a list of employees
3. User requests to delete a specific employee in the list

4. PeopleSoft deletes the employee

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. PeopleSoft shows an error message.

    Use case resumes at step 2.

Use case: Update an employee’s data

MSS

1. User requests to list employees
2. PeopleSoft shows a list of employees
3. User requests to edit a specific employee in the list with the updated information

4. PeopleSoft updates the employee to match user input

   Use case ends.

Extensions

• 2a. The list is empty.

  Use case ends.

• 3a. The given index is invalid.

  • 3a1. PeopleSoft shows an error message.

    Use case resumes at step 2.

Non-Functional Requirements

1. Should work on any mainstream OS as long as it has Java 11 or above installed.
2. Should be able to hold up to 1000 persons without a noticeable sluggishness in performance for typical usage.
3. Should not rely on database-management systems to store data.
4. Should not require an installer; should be packaged into a single reasonably-sized (i.e. within 100MB) JAR file.
5. Should not be hosted on remote servers.
6. Should not make use of proprietary third-party frameworks, libraries and services.
7. Should have a responsive GUI. GUI should function well (i.e., should not cause any resolution-related inconveniences to the user) for standard screen resolutions and higher and for screen scales 100% and 125%. GUI should be usable - even if suboptimal - for resolutions 1280x720 and higher and for screen scales 150%.
8. 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.

Glossary

• Mainstream OS: Windows, Linux, Unix, OS-X
• Standard screen resolution: 1920x1080

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Appendix: Instructions for manual testing

Given below are instructions to test the app manually.

Launch and shutdown

1. Initial launch

   1. Download the jar file and copy into an empty folder

   2. Double-click the jar file Expected: Shows the GUI with a set of sample contacts. The window size may not be optimum.

2. Saving window preferences

   1. Resize the window to an optimum size. Move the window to a different location. Close the window.

   2. Re-launch the app by double-clicking the jar file.
      Expected: The most recent window size and location is retained.

Adding an employee

Adding an employee while employees are being shown

Prerequisites: List all employees using the list command. Multiple employees in the list.

• Test case: personadd n/Nicole Tan p/99338558 e/nicole@stffhub.org a/1 Tech Drive, S138572 r/37.50 t/Hardware t/Senior
  Expected: An employee with the corresponding details will be added to the end of the employee list. Details of the added employee will be shown in the status message.
• Test case: personadd p/99338558 e/nicole@stffhub.org a/1 Tech Drive, S138572 r/37.50 t/Hardware t/Senior
  Expected: No employee is added. The expected format of the personadd command will be shown in the status message.
• Test case: personadd n/Nicole p/9 e/nicole@stffhub.org a/1 Tech Drive, S138572 r/37.50 t/Hardware t/Senior
  Expected: No employee is added. The expected format of Phone will be shown in the status message.

Other incorrect personadd commands to try: personadd, personadd n/Nicole, ...
Expected: Similar to previous.

Deleting an employee

1. Deleting an employee while all employees are being shown

   1. Prerequisites: List all employees using the list command. Multiple employees in the list.

   2. Test case: delete 1
      Expected: First employee is deleted from the list. Details of the deleted employee shown in the status message.

   3. Test case: delete 0
      Expected: No employee is deleted. Error details shown in the status message. Status bar remains the same.

   4. Other incorrect delete commands to try: delete, delete x, ... (where x is larger than the list size)
      Expected: Similar to previous.

2. Deleting an employee after a find command is executed

   1. Prerequisites: List all persons using the list command. Multiple persons in the list.

   2. Test case: delete 1
      Expected: First contact is deleted from the observable list. Details of the deleted contact shown in the status message. Entering the list command shows that the employee that was originally in the first index is not deleted (unless the position of the employee was the same after the find command).

   3. Test case: delete 0
      Expected: No person is deleted. Error details shown in the status message. Status bar remains the same.

   4. Other incorrect delete commands to try: delete, delete x, ... (where x is larger than the list size)
      Expected: Similar to previous.