//package Posmatrac;

import java.util.*;

// "Subject"
abstract class Stock
{
	// polja
	protected String symbol;
	protected double price;
	private ArrayList investors = new ArrayList();

	// konstruktor
	public Stock( String symbol, double price )
	{
		this.symbol = symbol;
		this.price = price;
	}

	// metodi
	public void Attach( Investor investor )
	{
		investors.add( investor );
	}

	public void Detach( Investor investor )
	{
		investors.remove( investor );
	}

	public void Notify()
	{
		for( int i=0; i<investors.size(); i++ )
		{
			Investor in = (Investor) investors.get(i);
			in.Update( this );
		}
	}

	// svpjstva
	public double getPrice()
	{
		return price; 
	}

	public void setPrice( double value )
	{
		price = value;
		Notify(); 
	}

	public String getSymbol()
	{
		return symbol; 
	}

	public void setSymbol( String value )
	{
		symbol = value; 
	}
}

// "ConcreteSubject"

class IBM extends Stock
{
	// konstruktor
	public IBM( String symbol, double price )
	{
		super( symbol, price );
	}
}

// "Observer"
interface IInvestor
{
	// Metodi
	void Update( Stock stock );
}

// "ConcreteObserver"
class Investor implements IInvestor
{
	// polja
	private String name;
	private String observerState;
	private Stock stock;

	// konstruktors
	public Investor( String name )
	{
		this.name = name;
	}

	// Metodi
	public void Update( Stock stock )
	{
		System.out.println( "obavesten je investitor "  + name + " sa " 
			+ stock.getSymbol() + "'promenama u " + stock.getPrice() );
	}

	// svojstva
	public Stock getStock()
	{
		return stock; 
	}

	
	public void setStock( Stock value)
	{
		stock = value; 
	}
}

/// Observer test

public class RealanSlucaj
{
	public static void main( String[] args )
	{
		// kreiraj investitore
		Investor s = new Investor( "Delta" );
		Investor b = new Investor( "Vero" );

		// kreiraj IBM akcije i prikaci investitore
		IBM ibm = new IBM( "IBM", 120.00 );
		ibm.Attach( s );
		ibm.Attach( b );

		// izmena cene akcija, tj. obavestenje investitora
		ibm.setPrice( 120.10 );
		ibm.setPrice( 121.00 );
		ibm.setPrice( 120.50 );
		ibm.setPrice( 120.75 );
	}
}