Klausur-2003-02-04

Lösung von Tudor, ohne Gewähr, siehe dazu Diskussion auf [1]

import java.util.*;

public class OrderedSetImpl extends ArrayList implements OrderedSet{
public OrderedSetImpl(){
		super();
	}
	
	public OrderedSetImpl(int initialCapacity){
		super(initialCapacity);
	}
	
	public boolean add(Object obj){
		if (obj==null){
			throw new NullPointerException();
		}
		int previousIndex = indexOf(obj);
		if (previousIndex != -1)
			return false;
		else {
			super.add(obj);
			return true;
		}
	}
	
	public boolean addAll(Collection collection){
		throw new UnsupportedOperationException();
	}
	
	public boolean addAll(int i, Collection collection){
		throw new UnsupportedOperationException();
	}
	
	public Object set(int i, Object obj){
		if (obj == null){
			throw new NullPointerException();
		}
		if (super.contains(obj)){
			return super.get(i);
		}
		else {
			Object altI = super.get(i);
			super.set(i,obj);
			return altI;
		}
	}
	
	public void add(int i, Object obj){
		if (obj == null){
			throw new NullPointerException();
		}
		if (super.contains(obj)){
			}
		else {
			super.set(i,obj);
			}
	}
}

---

import java.util.*;

public class QueueImpl implements Queue {

	private List myObjects;

	public QueueImpl(boolean withDuplicates) {

		if (withDuplicates) {
			myObjects = new LinkedList();
		} else {
			myObjects = new OrderedSetImpl();
		}
	}

	public boolean add(Object o) {
		return myObjects.add(o);
	}

	public Object remove(){
		return myObjects.remove(0);
	}
	
	public Object front(){
		return myObjects.get(0);
	}
	
	public boolean isEmpty(){
		return myObjects.isEmpty();
	}
	
	public int size(){
		return myObjects.size();
	}
	
	public String toString(){
		return myObjects.toString();
	}
}

zur letzten Frage, was bei der main-Methode rauskommt:

Erstmal nix, weil die Variable myQueue nicht als QueueImpl deklariert ist. Wenn man das dann tut ist das Ergebnis:

[Kevin, Frank]