MONITORS AND SEMAPHORES There is a reservation system for a

MONITORS AND SEMAPHORES

There is a reservation system for a movie theater used by all its box offices (BO). The movie theater has one room. Each BO can: bullet Request a reservation for a number of seats boolean reserve (int seats). The BO cannot reserve more seats than are currently available. If a BO tries to reserve more seats than are available, it should block until there are enough seats to perform the reservation. If the reservation is successful, the operation reserve () should return true. bullet Cancel a number of seats (making them available) void cancel (int seats). You may assume that only a positive number of seats may be reserved or canceled. Also, you must assume that the monitor uses the E = W

Solution

FullDataBaseGenerator.java

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import java.awt.*;
//import javax.swing.*;
import java.awt.event.*;
import java.util.*;
import java.io.*;

public class FullDataBaseGenerator
{

   // Method that takes a String (from the film time cb)
   // And returns a String of the name of the text file it belongs to
   public static String returnFileName(String input)

   {
       String timeFileName = input;

       if (input.equals(\"1.00 PM\"))
       {
           timeFileName = \"SEAT DATABASE 1.00 PM.txt\";
       }
       else if (input.equals(\"3.00 PM\"))
       {
           timeFileName= \"SEAT DATABASE 3.00 PM.txt\";
       }
       else if (input.equals(\"5.00 PM\"))
       {
           timeFileName= \"SEAT DATABASE 5.00 PM.txt\";
       }
       else if (input.equals(\"7.00 PM\"))
       {
           timeFileName = \"SEAT DATABASE 7.00 PM.txt\";
       }
       else if (input.equals(\"9.00 PM\"))
       {
           timeFileName= \"SEAT DATABASE 9.00 PM.txt\";
       }

       return timeFileName;
   }

   //Method to Create a blank database of all the seats available
   public ArrayList<Integer> seatNumberCalculate()
   {
       // Variables to values for each block of seats
       int A = 0;
       int B = 0;
       int C = 0;

       // ArrayList to hold the values
       ArrayList<Integer> al = new ArrayList<Integer>();

       // Add zero at the start of the array to act as a defauilt value for the cbs
       al.add(0);

       // Calculate the seatnumbers and add them into the array
       for (int i=0; i < 36; i++)
       {
           A = 101+i;
           al.add(A);
       }
       for (int i = 0; i < 40; i++)
       {
           B = 201+i;
           al.add(B);
       }
       for (int i = 0; i < 36; i++)
       {
           C = 301+i;
           al.add(C);
       }

       return al;
   }

   // Method that generates a fresh database
   public void FullDataBaseGeneration(String file_name)
   {
       // Name of database (calculated by \'returnFileName\' method)
       String name = file_name;

       // Get ArrayList cointaining values for every seat
       ArrayList <Integer> input = seatNumberCalculate();

       // Name of database
       String selectedTime = returnFileName(name);

       File selectedTimeFile = new File(selectedTime);

       try{
       // if the file exists, do not create a new file (leave existing file alone)
       if (selectedTimeFile.exists() == true)
       {
           return;
       }
       }catch (Exception ex){
       System.err.println(ex.getMessage());
       }

       // if the file doesnt exist..
       try{

           // create a new file with the correct name
           selectedTimeFile.createNewFile();

           // Start dependencies for file reading
           FileInputStream fs = new FileInputStream(selectedTimeFile.toString());
           DataInputStream in = new DataInputStream(fs);
           BufferedReader br = new BufferedReader(new InputStreamReader(in));

           //Start dependancy for file writing
           String stringLine;
           BufferedWriter fw1 = new BufferedWriter(new FileWriter(selectedTime));

           // Write a ; to the file (this is needed to add some content to replace)
           fw1.write(\";\");
           // Close this write dependancy
           fw1.close();

           // While there are Lines left to be read
           while ((stringLine = br.readLine()) != null)
           {
               // Create dependencies for writing to same file
               BufferedWriter fw = new BufferedWriter(new FileWriter(selectedTime));
               int x=0;
               // Iterate through the new edited array (orginal array minus selected seat)
               while(x < input.size())
               {
                   // Rewrite every line of the text file with each entry in the new array
                   String line = input.get(x).toString();
                   fw.write(line + \";\");
                   x++;
               }
               //Close the file writing dependency
               fw.close();
           }

           }catch (Exception ex){
                   System.err.println(ex.getMessage());}

   }

       // Method for returning an array of the available seats, for passing into the Main class
       public static ArrayList<Integer> AvailableSeatsArrayReturn(String file_name)
       {
           ArrayList<Integer> temp = new ArrayList<Integer>();

           String name = file_name;
           String selectedTime = returnFileName(name);
           File selectedTimeFile = new File(selectedTime);

           if (selectedTimeFile.exists())
           {

               try{

              FileInputStream fs = new FileInputStream(selectedTimeFile.toString());
               DataInputStream in = new DataInputStream(fs);
               BufferedReader br = new BufferedReader(new InputStreamReader(in));
               String stringLine;

               while ((stringLine = br.readLine()) != null)
               {
                   String[] array = stringLine.split(\";\");

                   // For every object in the array, built from items in the text file
                   for (int i=0; i < array.length; i++)
                   {
                       // Convert the item to an integer
                       Integer num = Integer.parseInt(array[i]);

                       // Add Item to arraylist to be rerturned
                       temp.add(num);
                   }
               }

               in.close();

               }catch (Exception ex){System.err.println(ex.getMessage());}

           }
           return temp;
       }

}