public class Runner 
    {
    	//data read in from text files.
    	public static String[] halls = ResidentInput.getHallNames();
    	public static int[] rooms = ResidentInput.getHallRooms();
    	public static String[] jerryHallList = ResidentInput.getEnrollRequestsJerry();
    	public static String[] tomHallList = ResidentInput.getEnrollRequestsTom();
    	
        public static void main(String args[]) 
        {
        	Entry entry = new Entry();
	        Thread EnrollThreadTom = new Thread(new EntryPerson("Tom", entry));
	        Thread EnrollThreadJerry = new Thread(new EntryPerson("Jerry", entry));

	       	EnrollThreadTom.start();   
	        EnrollThreadJerry.start(); 
        }
        
    }












import java.lang.Runnable;

public class EntryPerson implements Runnable
{
	//attributes
	private String name;
	private Entry entry;
	
	//constructor
	public EntryPerson(String name, Entry entry)
	{
		
		this.name = name;
		this.entry = entry;
	}
	
	public synchronized void createEntry()
	{	
		System.out.println(this.name);
	}

	//runnable
	public void run()
	{
		for (int x=0; x<10; x++)
		{
			synchronized(entry)
			{
				//wait while other tread probably doens't work...
				while(entry.beingUsed())
				{
					if (this.name.equalsIgnoreCase("Tom"))
					try
					{
						System.out.println("waiting...");
						entry.wait();
					}
					catch (InterruptedException e){}
				}
			}
			entry.setBeingUsed(true);
			synchronized(entry)
			{
				entry.notifyAll();
			}
			createEntry();
			
			entry.setBeingUsed(false);
			synchronized(entry)
			{
				entry.notifyAll();
			}
		}
	}
}













public class Entry 
{
	boolean used = false;
	
	public boolean beingUsed()
	{
		return used;
	}
	
	
	public void setBeingUsed(boolean used)
	{
		this.used = used;
	}
}






















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

public class ResidentInput {

  public static String[] getHallNames() {

    ArrayList<String> namesArray;
    String[] names = null;

    namesArray = loadFile("hallnames.txt");

    if (namesArray != null) {
      names = (String[])namesArray.toArray(new String[0]);
    }

    return names;
  }

  public static int[] getHallRooms() {

    ArrayList roomsArray;
    int[] rooms = null;

    String intString;

    roomsArray = loadFile("hallrooms.txt");

    if ((roomsArray != null) && (roomsArray.size() > 0)) {

      rooms = new int[roomsArray.size()];

      for (int i = 0; i < roomsArray.size(); i++) {

        intString = (String)roomsArray.get(i);
        try {
          rooms[i] = Integer.parseInt(intString);
        }
        catch (NumberFormatException e) {
          rooms[i] = -1;
          System.err.println("Error: bad value on line " + (i + 1) +
                             " of hallrooms.txt");
        }
      }
    }
    
    return rooms;
  }

  public static String[] getEnrollRequestsTom() {

    ArrayList<String> namesArray;
    String[] names = null;

    namesArray = loadFile("requeststom.txt");

    if (namesArray != null) {
      names = (String[])namesArray.toArray(new String[0]);
    }

    return names;
  }

  public static String[] getEnrollRequestsJerry() {

    ArrayList<String> namesArray;
    String[] names = null;

    namesArray = loadFile("requestsjerry.txt");

    if (namesArray != null) {
      names = (String[])namesArray.toArray(new String[0]);
    }

    return names;
  }

  protected static ArrayList<String> loadFile(String fileName) {

    if ((fileName == null) || (fileName == ""))
      throw new IllegalArgumentException();

    String line;
    ArrayList<String> lines = new ArrayList<String>();

    try {    
      BufferedReader in = new BufferedReader(new FileReader(fileName));

      if (!in.ready()) {
        throw new IOException();
      }

      while ((line = in.readLine()) != null) {
        if (!line.trim().equals("")) {
          lines.add(line);
        }
      }

      in.close();
    }
    catch (IOException e) {
      System.out.println(e);
      return null;
    }

    return lines;
  }

}