OOP Lab Task 4

Required Tutorials

• The Object Oriented Paradigm; Classes and Objects
• Notions About the Java Language
• Writing and Executing a Java Program
• Java Syntax; A Program's Lexical Structure
• Coding Conventions
• Advanced Notions About Object Oriented Programming
• Java Application Programming Interface (API) (EN)
• Exception Handling
• Input/Output Streams
• Serialization
• Network Sockets

Requirements

1. Implement a class called ClientPeer with the following characteristics:
   • The class constructor takes as arguments a String (the user/sender name) and a reference to a pre-initialized Socket.
   • The class implements two methods:
     • void sendMessage(String message) - creates a Message object and serializes it, utilising the available Socket.
     • void sendMessage(String message, String receiver) - creates a PrivateMessage object and serializes it, utilising the available Socket.
2. Implement a class called TextClient, which is executable (has a main method), with the following characteristics:
   • The main method opens a Socket on the localhost (127.0.0.1) on port 9000
   • While the socket connection is active, read strings of characters from the keyboard (utilizing the Console class - see System.console()) and call the sendMessage methods specified above (Note: You may choose any formatting to identify a private message, but please describe this format in the homework submission e-mail; one example is /w John Hello! which identifies a private message to user John, with the content "Hello!").
3. Implement a class called ServerPeer with the following characteristics:
   • The class constructor takes as argument a reference to a pre-initialized Socket.
   • While the socket connection is active, it deserializes objects of type Message and prints their formatted contents to the screen.
4. Implement a class called Server, which is executable (has a main method), with the following characteristics:
   • The main method must utilize an object of type ServerConfig to read a port number from a configuration file
   • Utilizing the identified port number, opens a ServerSocket and listens to connections,
   • Once a client is connected, creates a ServerPeer object, which utilizing the Socket obtained from the ServerSocket, reads objects from the stream, according to point 3 above.
5. Modify the Message and PrivateMessage classes such that they are serializable.