Java Q&A
by Eric J. Bruno

Listing One
public class QuoteSource 
{
    protected Vector listeners;
    public QuoteSource() 
    {
    }

    public void addListener(Object listenerObj)
    {
        listeners.add( listenerObj );
    }

    public void synchronized fire_quoteChange(double newQuote)
    {
        QuoteEvent qe = new QuoteEvent( this, newQuote );

        // give ...