001/*
002 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.graph.iterators;
024
025import java.util.*;
026
027import com.oracle.graal.graph.*;
028
029public abstract class NodeIterator<T extends Node> implements Iterator<T> {
030
031    protected T current;
032
033    protected abstract void forward();
034
035    @Override
036    public boolean hasNext() {
037        forward();
038        return current != null;
039    }
040
041    @Override
042    public T next() {
043        forward();
044        T ret = current;
045        if (current == null) {
046            throw new NoSuchElementException();
047        }
048        current = null;
049        return ret;
050    }
051
052    @Override
053    public void remove() {
054        throw new UnsupportedOperationException();
055    }
056}