///////////////////////////////////////////////////////////////////////////////// Copyright (c) 2001, Eric D. Friedman All Rights Reserved.//// 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 General Public License for more details.//// You should have received a copy of the GNU Lesser General Public// License along with this program; if not, write to the Free Software// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.///////////////////////////////////////////////////////////////////////////////package gnu.trove;import java.util.ConcurrentModificationException;import java.util.NoSuchElementException;/** * Abstract iterator class for THash implementations.  This class provides some * of the common iterator operations (hasNext(), remove()) and allows subclasses * to define the mechanism(s) for advancing the iterator and returning data. * * @author Eric D. Friedman * @version $Id: TIterator.java,v 1.1.1.1 2003/07/14 19:36:04 mccallum Exp $ */abstract class TIterator {    /** the data structure this iterator traverses */    protected final THash _hash;    /** the number of elements this iterator believes are in the     * data structure it accesses. */    protected int _expectedSize;    /** the index used for iteration. */    protected int _index;    /**     *  Create an instance of TIterator over the specified THash.     */    public TIterator(THash hash) {        _hash = hash;        _expectedSize = _hash.size();        _index = _hash.capacity();    }    /**     * Returns true if the iterator can be advanced past its current     * location.     *     * @return a <code>boolean</code> value     */    public boolean hasNext() {        return nextIndex() >= 0;    }    /**     * Removes the last entry returned by the iterator.     * Invoking this method more than once for a single entry     * will leave the underlying data structure in a confused     * state.     */    public void remove() {        if (_expectedSize != _hash.size()) {            throw new ConcurrentModificationException();        }        _hash.removeAt(_index);        _expectedSize--;    }    /**     * Sets the internal <tt>index</tt> so that the `next' object     * can be returned.     */    protected final void moveToNextIndex() {        // doing the assignment && < 0 in one line shaves        // 3 opcodes...        if ((_index = nextIndex()) < 0) {            throw new NoSuchElementException();        }    }    /**     * Returns the index of the next value in the data structure     * or a negative value if the iterator is exhausted.     *     * @return an <code>int</code> value     */    abstract protected int nextIndex();} // TIterator