67 lines
1.4 KiB
Java
67 lines
1.4 KiB
Java
import java.util.*;
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public class FunctionalSetIterator<E> implements Iterator<E>
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{
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/** Unsere Menge */
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private FunctionalSet<E> set;
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/** Aktuelles Element */
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private SimpleFunctionalSet<E> current;
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/** Bereits gesehene Elemente */
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private Set<Object> seen = new FunctionalSet<>();
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/** Aktuelles Element */
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private E currentElem;
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/** Ob das aktuelle Element bereits entfernt wurde. */
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private boolean hasBeenRemoved = true;
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private void skipToNext()
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{
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while (true)
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{
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current = current.getRemainingSet();
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if (current instanceof RemoveSet)
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seen.add(((RemoveSet) current).getObject());
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else if (!(current instanceof AddSet) || !seen.contains(((AddSet)current).getElement()))
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break;
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}
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}
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public FunctionalSetIterator(FunctionalSet<E> set, SimpleFunctionalSet<E> head)
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{
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this.set = set;
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current = head;
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if (current instanceof RemoveSet)
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{
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seen.add(((RemoveSet)current).getObject());
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skipToNext();
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}
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}
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@Override
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public boolean hasNext()
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{
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return !(current instanceof EmptySet);
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}
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@Override
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public E next()
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{
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if (!hasNext())
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throw new NoSuchElementException();
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currentElem = ((AddSet<E>) current).getElement();
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seen.add(currentElem);
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skipToNext();
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hasBeenRemoved = false;
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return currentElem;
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}
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@Override
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public void remove()
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{
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if (hasBeenRemoved)
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throw new IllegalStateException("Das Element wurde schon entfernt");
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set.remove(currentElem);
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hasBeenRemoved = true;
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}
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}
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