A little Java-"Program"

Anwendung

import java.util.*;


public class Anwendung {

  /**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		List<Land> laender = new ArrayList<Land>();
		
		Land nrw = new Bundesland("Nordrhein-Westfalen");
		Land he = new Bundesland("Hessen");
		
		Stadt f = new Stadt ("Frankfurt", false);
		Stadt wi = new Stadt ("Wiesbaden", true);
		Stadt d = new Stadt ("Duesseldorf", true);
		Stadt bi = new Stadt("Bielefeld", false);
		
		laender.add(nrw);
		laender.add(he);
		
		Collections.sort(laender);
		
		for(Land land: laender) {
			System.out.println(land);
		}
	}

}

Bundesland

import java.util.ArrayList;


public class Bundesland extends Land {

  public Bundesland(String name) {
		super(name);
	}

	@Override
	public int compareTo(Land vergleichsLand) {
		return this.getName().compareTo(vergleichsLand.getName());
	}
	
	
}

Land

import java.util.*;

public abstract class Land implements java.lang.Comparable<Land> {

  private String name;
	private List<Stadt>  staedteListe = new ArrayList<Stadt>();

	public Land(String name) {
		this.name = name;
	}

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public void setStadt (Stadt pStadt) {
		staedteListe.add(pStadt);
	}
	public Stadt getStadt(int pos) {
		return staedteListe.get(pos);
	}
	
	public Stadt getHauptstadt() {
		for (Stadt s: staedteListe) {
			if (s.isCapital())
				return s;
		}
		return null;
	}

	@Override
	public String toString() {
		String output = "Name: " + this.getName();
		return output;
	}
	
	@Override
	public int compareTo(Land vergleichsLand) {
		return this.getName().compareTo(vergleichsLand.getName());
	}
}

Stadt

import java.util.*;
public class Stadt implements Comparable<Stadt> {
  private String name;
	private boolean isCapital;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public boolean isCapital() {
		return isCapital;
	}

	public void setCapital(boolean isCapital) {
		this.isCapital = isCapital;
	}

	public Stadt(String name, boolean isCapital) {
		this.name = name;
		this.isCapital = isCapital;
	}
	
	public int compareTo(Stadt vergleichsStadt) {
		return this.getName().compareTo(vergleichsStadt.getName());
	}

}