EmptyIterator.java

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package org.apache.cayenne.ashwood.graph;

import java.util.NoSuchElementException;

class EmptyIterator<E, V> implements ArcIterator<E, V> {

	@SuppressWarnings({ "rawtypes" })
	private static final ArcIterator EMPTY_ITERATOR = new EmptyIterator<>();
	
	@SuppressWarnings("unchecked")
	static <E, V> ArcIterator<E, V> instance() {
		return EMPTY_ITERATOR;
	}

	@Override
	public E getOrigin() {
		return null;
	}

	@Override
	public E getDestination() {
		return null;
	}

	@Override
	public boolean hasNext() {
		return false;
	}

	@Override
	public V next() {
		throw new NoSuchElementException("Iterator contains no elements");
	}

	@Override
	public void remove() {
		throw new IllegalStateException("Iterator contains no elements");
	}
}