Java File Infection Simulation and Implementation

This document details the implementation of a Virus class in Java, focusing on binary file manipulation and stream handling.

Java Source Code for Virus Simulation

import java.io.*;
import java.util.*;

/**
 * Write a description of class Virus here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
public class Virus
{
    // Campos  
    private File virusFile;  // Fichero con el código binario del virus
    public static final int SIZE = 100;

    /**
     * Constructor for objects of class Virus
     */
    public Virus( String nombre )
    {
        this.virusFile = new File(nombre);
    }

    /**
     * Método get para el campo this.virusFile
     * 
     * @return     this.virusFile
     */
    public File getFile()
    {
        return this.virusFile;
    }

    /**
     * Método que infecta el fichero dado como parámetro. El proceso de infección utilizado se explica en el enunciado
     * de la práctica.
     * 
     * @param  nombre   fichero por infectar
     */
    public void InfectarFichero( String nombre )
    {
        File f = new File(nombre);
        long t = f.length();
        int pos;
        Random gen = new Random();
        pos = gen.nextInt((int)t)/SIZE;
        System.out.println("El virus se inserta en el bloque " + pos);
        try{
            FileInputStream vin = new FileInputStream(this.virusFile);
            FileInputStream in = new FileInputStream(f);
            FileOutputStream out = new FileOutputStream("infectado");

            int nleido = 0;
            byte [] buffer = new byte[SIZE];
            for ( int i = 0 ; i < pos; i++){
                if( (nleido = in.read (buffer)) != -1)
                    out.write(buffer , 0 ,nleido);
            }

            buffer = new byte[1024];
            while( (nleido = vin.read(buffer)) != -1){
                out.write(buffer, 0, nleido);
            }

            while( (nleido = in.read(buffer)) != -1){
                out.write(buffer, 0 , nleido);
            }
            in.close();
            vin.close();
            out.close();

        }catch(FileNotFoundException e){
            System.out.println("No existe el fichero");
        }catch(IOException e){
            System.out.println("Error E/S");
        }
    }

    public static void main( String args[] )
    {
        Virus v = new Virus( "Fundamentos.virus");
        v.InfectarFichero("Actividad6_2_Virus.pdf" );
    }
}

Key Functionalities

• File Handling: Utilizes FileInputStream and FileOutputStream for binary data.
• Random Insertion: Determines a random block position for the infection.
• Exception Management: Implements try-catch blocks for robust error handling.