🧶 OOP-JSF-Binding

Demonstrating Object-Oriented Programming (OOP) principles where objects controls their own persistence and display logic within a Java web application using Jakarta EE and PrimeFaces.

Overview

The application manages Tasks and Folders in a hierarchical structure and showcases how UI components can be directly bound to domain objects.

Quick Start

The application can be started as a WAR on a Jakarta EE compliant server (e.g., WildFly, Payara) or locally as a JAR (with embedded WildFly), using an H2 in-memory database.

Required: Java 11+

1. run in cmd: mvn package - standalone application - as executable .jar

• or optional: mvn install - jee server application - as deployable .war

2. then browse: http://localhost:8080/index.xhtml

Architecture and OOP Principles

The application adheres to classic OOP principles:

• Abstraction: The interfaces org.todo.Task and org.todo.Folder define the fundamental behavior as operations for tasks and folders, independent of their concrete implementation.
• Encapsulation: The implementations org.todo.task.DbTask and org.todo.folder.DbFolder encapsulate database logic and provide methods for display and persistence.
• Inheritance: The application uses inheritance, for instance, by extending framework classes like LazyDataModel<Task> in org.todo.task.TaskTable.
• Polymorphism: UI components and controllers work with the interfaces, allowing various implementations (e.g., for testing or different data sources) to be easily swapped.

Components

• Application: The root Composition of all implementations in the package app/ contains main Startup and Dependency-Injection.
• Domain: The main interfaces in the namaspace (package) todo/ and their implementations for tasks task/ and folders folder/.
• Persistence: The class org.todo.app.H2Db initializes the database and provides test data.
• Presentation: Managed Beans like org.todo.task.TaskForm bind UI components directly to the domain objects.
• Webservice: REST API endpoints such as org.todo.task.TaskResource allow access to tasks as JSON resources.

UI Binding

The application demonstrates how JSF components can be connected directly to the domain object methods via the binding attribute.

• Example: The displayTo(HtmlOutputText output) method in the Task object directly sets the representation onto the UI element.

Exemplary OOP Implementation

• Tasks and folders are modeled as objects that control their own persistence and display logic.
• The UI components are updated directly by the objects themselves, through methods like displayTo(Tree tree) or displayTasksTo(DataTable table).

Project Links

• src/main/java/org/todo/Task.java
• src/main/java/org/todo/Folder.java
• src/main/java/org/todo/task/DbTask.java
• src/main/java/org/todo/folder/DbFolder.java
• src/main/java/org/todo/task/TaskForm.java
• src/main/java/org/todo/task/TaskTable.java
• src/main/java/org/todo/task/TaskResource.java
• src/main/java/org/todo/app/H2Db.java

References

Writing Properties Bound to Component Instances.