import java.util.*;
import java.io.*;
//
//
// GameWorld
//
// Last modification date : November 13, 1997
//
public class GameWorld implements Serializable
{
	// List of Location objects
	private Vector locations;

	// List of Exit objects
	private Vector exits;

	// The current location of the player
	private Location currentLocation;

	// Character width for descriptions
	private int charWidth;

	// Output stream for gaming system
	transient private WidthLimitedOutputStream output;

	// GameWorld constructor
	public GameWorld()
	{
		// Instantiate vector lists for location/exits
		locations = new Vector();
		exits = new Vector();

		// The default location of a player isn't known
		currentLocation = null;

		// By default, use standard output
		setOutputStream (System.out, 80);
	}

	// GameWorld constructor
	public GameWorld(int characterWidth )
	{
		// Call default constructor
		this();

		charWidth = characterWidth;		
	}

	/** Returns the current location of the player */
	public Location getCurrentLocation()
	{
		return currentLocation;
	}

	/** Assigns a new location to the current location of the player */
	public void setCurrentLocation(Location newLocation)
	{
		currentLocation = newLocation;
	}

	/** Adds a new exit to the gaming system */
	public void addExit( Exit exit )
	{
		// Check if exit vector already contains exit 
		if (! exits.contains ( exit ) )
			// Exit doesn't exist, and must be added
			exits.addElement ( exit);
	}

	/** Adds a new location to the gaming system */
	public void addLocation( Location location )
	{
		// Check if location vector already contains location 
		if (! locations.contains ( location ) )
			// Location doesn't exist, and must be added
			locations.addElement ( location );
	}

	/** Sets the output stream for the gaming systewm */
	public void setOutputStream(OutputStream out, int width)
	{
		output = new WidthLimitedOutputStream(out, width) ;
	}

	/** Shows the current game location */
	public void showLocation()
	{
		// Show title
		output.println ( currentLocation.getTitle() );

		// Show description
		output.println ( currentLocation.getDescription() );

		output.println();

		// Show available exits		
		output.println ( "Available exits :" );

		// Traverse elements of vector
		for (Enumeration e = currentLocation.getExits().elements(); e.hasMoreElements();)
		{
			// Get next exit
			Exit an_exit = (Exit) e.nextElement();

			// Print exit to our output stream
			output.println (an_exit.toString());
		}	
	}

}