gistfile1.java

port = new Airport(1);
port = new Airport("/custom/path.xml");
port.save();
port.save("/custom/path.xml")

private XMLHandler handler;

public Airport() {
	this(240, 50, 300, "Heathrow");
	handler = new XMLHandler();
}

// load from XML/airport_ID.xml
public Airport(int airportId) {
	handler = new XMLHandler(airportId);
	handler.initializeAirport(this);
}
  
// could point to a user-specified location
public Airport(String xmlLocation) {
	handler = new XMLHandler(xmlLocation);
	handler.initializeAirport(this);
}

// When initialized from airportID or xmlLocation, save back to the same file.
// Otherwise save to the next free XML/airport_ID.xml
public void saveXML() {
	if (handler == null) {
		handler = new XMLHandler();
	}
	handler.saveAirport(this);
}
  
// No matter how it was initialized, save to xmlLocation. 
public void saveXML(String xmlLocation) {
	handler.saveAirport(this, xmlLocation);
}