freelancer, a freelancing platform simulation

freelancer is a high-performance Java application designed to simulate a gig economy platform. It efficiently manages user registrations, job matching, and month-to-month simulation updates using custom-built data structures.

The system is designed to handle large datasets of customers and freelancers, processing commands in real-time to match the best-suited freelancers to jobs based on a complex scoring algorithm.

Features

• User Management: Handles registration for Customers and Freelancers with unique IDs.
• Service Categories: Supports 10 distinct service types (e.g., Web Dev, Painting, Tutoring), each with specific skill requirements.
• Smart Matching Algorithm: Matches freelancers using a weighted Composite Score derived from:
  • Skill Proficiency (Technical, Communication, Creativity, Efficiency, Attention to Detail).
  • Customer Ratings.
  • Reliability (Completion vs. Cancellation ratio).
• Dynamic Skill Evolution:
  • Skills improve when a job is completed with a high rating (4.0+).
  • Skills degrade and penalties are applied if a freelancer cancels a job.
• Market Simulation:
  • Burnout System: Freelancers taking too many jobs risk burnout, significantly lowering their ranking.
  • Loyalty Tiers: Customers earn statuses (Bronze to Platinum) based on spending, unlocking platform subsidies.
  • Blacklisting: Supports both customer-specific blacklists and platform-wide bans for unreliable freelancers.

Technical Implementation

This project relies on custom implementation of core data structures rather than standard Java Collections (except ArrayList) to ensure optimized performance for specific operations.

Data Structures

• Custom HashTable (HashTable.java):

  • Uses Open Addressing with Quadratic Probing (hash + i*i) for collision resolution.
  • Implements Horner's Method for string hashing.
  • Supports dynamic resizing (finding the next prime number for capacity) to maintain low load factors.
  • Used for O(1) average time complexity user lookups (Customer/Freelancer retrieval).

• Custom MaxHeap (MaxHeap.java):

  • A binary heap implementation used as a Priority Queue.
  • Each Service maintains its own MaxHeap to keep freelancers sorted by their Composite Score in real-time.
  • Allows for efficient retrieval of the "Top K" freelancers for any given job request.

Object-Oriented Design

• Inheritance: Customer and Freelancer classes extend a base User abstract class.
• Command Pattern: The Main class acts as a parser, processing a stream of string commands to execute platform logic.

Project Structure

• Main.java: Entry point. Parses input files, processes commands (Register, Request, Employ, etc.), and manages the simulation loop.
• HashTable.java: Generic custom hash table implementation.
• MaxHeap.java: Priority queue implementation for ranking freelancers.
• User.java: Definitions for User, Customer, and Freelancer classes, including scoring logic.
• Service.java: Defines service types and holds the heap for that specific market sector.
• FileComparator.java: A utility tool to compare your output against expected test cases.

Installation & Usage

1. Clone the repository:

   git clone https://github.com/winterwitchy/freelancer
   cd freelancer

2. Compile the source code:

   javac *.java

3. Run the application: The program takes an input file containing commands and an output path for the logs.

   java Main <input_file> <output_file>

Example Input Command

register_customer cust1
register_freelancer free1 paint 150 75 60 50 85 90
request_job cust1 paint 2
complete_and_rate free1 5
simulate_month