CPU Scheduler Simulator

A Java-based simulation tool for CPU scheduling algorithms, implementing core concepts of operating systems and software design. The simulator supports multiple scheduling algorithms, including both preemptive and non-preemptive modes.

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Features

• Scheduling Algorithms:
  • First Come First Serve (FCFS)
  • Shortest Job First (SJF) (Preemptive & Non-preemptive)
  • Priority Scheduling (Preemptive & Non-preemptive)
  • Round Robin with configurable time quantum
• Interactive Simulation:
  • Add processes dynamically.
  • Select algorithms and modes (Preemptive or Non-preemptive).
  • View execution steps and scheduling decisions.

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Object-Oriented Design

Applied Principles

• Encapsulation:
  • Process attributes (ID, burst time, priority, etc.) are private with public getters/setters.
  • Scheduler logic is encapsulated within specific classes.
• Abstraction:
  • Scheduler interface provides a common contract for all scheduling algorithms.
• Polymorphism:
  • Algorithms are interchangeable via the Scheduler interface.
• Inheritance:
  • Shared logic and utility methods are leveraged across scheduling implementations.

SOLID Principles

• Single Responsibility:
  • Each class has a clear and focused responsibility, such as scheduling (Scheduler), representing a process (Process), or running simulations (Simulator).
• Open-Closed:
  • New algorithms can be added by implementing the Scheduler interface without modifying existing code.
• Liskov Substitution:
  • Any Scheduler implementation can replace another without altering the simulator’s behavior.
• Interface Segregation:
  • The design avoids forcing implementation of unnecessary methods by using lean, focused interfaces.
• Dependency Inversion:
  • The simulator depends on abstractions (Scheduler interface) rather than concrete implementations.

Design Patterns

• Strategy Pattern:
  • Scheduling algorithms are interchangeable and selected dynamically at runtime using the Scheduler interface.
• Factory Method Pattern:
  • Scheduler instances are created based on user-selected algorithms.

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Package Structure

src/
├── model/
│   └── Process.java           # Represents a process in the system.
├── scheduler/
│   ├── Scheduler.java         # Interface for scheduling algorithms.
│   ├── FirstComeFirstServeScheduler.java
│   ├── ShortestJobFirstScheduler.java
│   ├── PriorityScheduler.java
│   └── RoundRobinScheduler.java
├── simulation/
│   ├── Simulator.java         # Core simulation logic.
│   ├── SimulationMode.java    # Enum for preemptive/non-preemptive modes.
├── ui/
│   └── SimulatorUI.java       # UI for user interaction.

Contributions

Contributions are welcome! Please submit issues or pull requests to improve functionality or add new features.