Streaming App System in Java

Overview

The purpose of this project is to create a recommendation system for streams (music, podcasts or audiobooks) based on existing data about the application's users (listeners) and the creators of streams (musicians, podcast moderators, authors) or those accumulated during the running of the application.

Data Input

• the main method of the project is in the ProiectPoo class
• the main method gets as parameters 3 csv files with the information about the users, streamers and streams and a txt file with the commands that need to be implemented using that info for the app

Classes Structure

• ProiectPoo class: the main method
• StreamingApp class:
  • manages the streams, users, streamers
  • implements the Singleton Design Pattern
• ReadFromFiles class: reads from files the info about the streams, users, streamers and commands
• Commands abstract class: implements the Command Design Pattern in order to incapsulate the commands read from files into objects, each subclass will override the executeCommand generic method
  • AddCommand subclass
  • DeleteCommand subclass
  • ListenCommand subclass
  • RecommendCommand subclass
  • SurpriseCommand subclass
• StreamersFactory class: implements Singleton and Factory Design Patterns so that it creates streamer objects based on their type
• Streamer class:
  • AuthorAudioBook subclass
  • Musician subclass
  • Podcaster subclass
• User class: creates user objects
• Stream class: creates stream objects
• Request class: creates requests based on the List command
• ListRequestHandler interface: declares methods that will be implemented by the handlers
• ConcreteStreamerIdHandler class: handles requests for streamers (lists the streams of a streamer), it implements the ListRequestHandler interface
• ConcreteUserIdHandler class: handles requests for the users (lists the streams listened by the user), it implements the ListRequestHandler interface
• ListRequest class: implements the Chain of Responsibility Design Pattern, each handler in the chain will try to solve or pass the request

OOP Concepts used

• Abstraction: the Command class is abstract to avoid creating pure Command objects, since the objects from the subclasses were needed
• Encapsulation: the instance fields in the classes are declared private, can only be accessed through the public getters and setters
• Inheritance: by creating subclasses
• Polymorphism: each subclass of the Command class overrides the executeCommand method

Design Patterns used

• Creational Design Patterns: Singleton, Factory
• Behavioral Design Patterns: Command, Chain of Responsibility