/**
 * This obeys the Singleton design pattern.
 * Only one instance of Registry can be generated.
 * It is used by DateServer to keep track of the number of connections made.
 * The point is that each time the server requests an instance of
 * a Registry, it gets the same single instance.  So that instance's
 * field for keeping track of the connection count keeps getting incremented.
 * The synchronization step is from Metsker's Java Workbook book.
 * <br>Singleton Design Pattern example for COM1204 Summer 2003.
 *
 * @author Bob Futrelle
 * @version 0.1, 5 July 2003
 *
 */
 
public class Registry {

    private static Registry registry = null; // (the default in any case)
    private static final Object classlock = Registry.class;
    private int connectionCount;

    private Registry(){};

    public void addToCount() {
	connectionCount++;
    }

    public void report() {
	System.out.println("Count now " + connectionCount);
    }

    public static Registry getRegistry() {
	synchronized(classlock)
	    {
		if (registry == null)
		    {
			registry = new Registry();
		    }
		return registry;
	    }
    } // getRegistry
	
} // class Registry