DistributedDocDB - Simple Distributed Document Storage System

DistributedDocDB is a Java-based client-server application designed to store, retrieve, and delete files remotely over a network. This project demonstrates key concepts of concurrent programming and TCP socket communication by allowing multiple clients to interact with the server simultaneously.

Idea/Workflow

DistributedDocDB is my little experiment in making document storage simple and interactive. The server keeps all files in a dedicated data/ folder, while clients can connect and use commands like PUT or GET to save and retrieve files. The goal is to see concurrency, networking, and file management working together in a real project — and it’s still evolving with upcoming features like LIST and REPLACE to make managing files even easier.

Upcoming Features / Adjustments

The following commands are planned additions to improve file management. They are not yet implemented but are part of ongoing development:

• LIST: Will display all files currently stored in the server’s data/ directory. This will help users quickly see which files exist on the server.
• REPLACE <new_content>: Will replace the content of an existing file without creating a new one if it does not exist. This ensures safe updates to existing files without accidental creation of new files.

Features

• PUT : Upload and save a file with specified content to the server.
• GET : Retrieve the content of a file from the server.
• DELETE : Remove a file from the server’s storage.
• EXIT: Close the client connection gracefully.

Architecture

• Server (DistributedDocDBServer.java):
  Listens on a TCP port, accepts client connections, processes commands, and manages file storage under the data/ directory.

• Client (Client.java):
  Provides a command-line interface to send commands to the server and display server responses.

• Supporting classes (Task.java, WorkerThread.java):
  Handle client requests and server concurrency.

Setup and Running

Prerequisites

• Java Development Kit (JDK) 8 or later installed
• Basic terminal/command line knowledge

Steps

1. Clone the repository:

   git clone https://github.com/mihaelacoman1/DataStructureEngine
   cd DataStructureEngine

2. Compile the Java files:

   javac project/*.java

3. Create the data directory to store files:

   mkdir data

4. Start the server (keep this terminal open):

   java project.DistributedDocDBServer

5. Open a new terminal and start the client:

   java project.Client

6. Use the client commands as prompted:

   • PUT <filename> <content>
   • GET <filename>
   • DELETE <filename>
   • EXIT

Example Usage

PUT test.txt HelloWorld
GET test.txt
DELETE test.txt
EXIT