/* * JVSTM: a Java library for Software Transactional Memory * Copyright (C) 2005 INESC-ID Software Engineering Group * http://www.esw.inesc-id.pt * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * Author's contact: * INESC-ID Software Engineering Group * Rua Alves Redol 9 * 1000 - 029 Lisboa * Portugal */ package jvstm.cps; import java.util.Iterator; import java.util.NoSuchElementException; public class ChainedIterator<E> implements Iterator<E> { private Iterator<? extends Iterator<? extends E>> iterators; private Iterator<? extends E> current; public ChainedIterator(Iterator<? extends Iterator<? extends E>> iterators) { this.iterators = iterators; if (iterators.hasNext()) { this.current = iterators.next(); updateCurrent(); } else { this.current = null; } } private void updateCurrent() { while ((current != null) && (! current.hasNext())) { current = (iterators.hasNext()) ? iterators.next() : null; } } public boolean hasNext() { return (current != null); } public E next() { if (current != null) { E result = current.next(); updateCurrent(); return result; } else { throw new NoSuchElementException(); } } public void remove() { throw new UnsupportedOperationException(); } }