Question

I am building an application with a Room class which is abstract and a Standard class which inherits from Room. I have then created a Hostel class. Within the Hostel class is ArrayList<Room> rooms to which rooms can be added. I have created a method in the Hostel class which shows all available rooms but when I try and instantiate this in another class (MainGUI) nothing is shown. As far as I can see this is because I am creating a new hostel each time I click the button but would like to know how to pass the data across instead of creating a new hostel each time. Below are the relevant snippets of code.

Hostel Class

public Hostel()
{
    rooms = new ArrayList<Room>();
}

public void showAvail()
{
    for (Room room : rooms)
    {
        if (room.available == true) 
        {
                 theString = room.getRoomData() + "\n";
                 //System.out.println("Available Rooms" + "\n" + theString);
                 JOptionPane.showMessageDialog(null,theString);
        }
    }
}

public void addRoom(Room theRoom)
{
    rooms.add(theRoom);
}

MainGUI Class

roomsFreeB.addActionListener(new ActionListener()
{
    public void actionPerformed(ActionEvent e)
    {
        Hostel host = new Hostel();
        host.showAvail();
    }
});

Any help would be appreciated

Answer 1

Your problem is exactly what you thought, you are making a new ArrayList each time you click the button so you will never see the data. You should begin by creating a hostel object in your MainGUI class,

private Hostel hostel;

this will allow previously entered information to be referenced