source: liacs/cvp/java/first/Database.java@ 422

/*

 * Rick van der Zwet

 * 0433373

 * Java programming assigment 1.2

 * Licence: BSD

 * $Id: Database.java 270 2007-10-13 13:45:29Z rick $

 */



class Database

{

// Read lock, call next person

// Write lock, call next person when done

    private int readlock = 0;

    private boolean  writelock = false;



    private String value = new String("INIT");



    Database () {}; // constructor



    synchronized void get_readlock ()

    {

        while (writelock)

        {

            try { wait(); } catch (InterruptedException e)

            {

                System.out.println("interruptedException caught");

            }

        }

        readlock++;

    }



    synchronized String read ()

    {

        return (value);

    }



    synchronized void release_readlock ()

    {

        readlock--;

        notify();

    }



    synchronized void get_writelock()

    {

        while (writelock && readlock > 0)

        {

            try { wait(); } catch (InterruptedException e)

            {

                System.out.println("interruptedException caught");

            }

        }

        writelock = true;

    }



    synchronized void write (String text)

    {

        value = value + ":" + text;

    }



    synchronized void release_writelock()

    {

        writelock = false;

        notify();

    }

}