/* This file is part of the db4o object database http://www.db4o.com
Copyright (C) 2004 - 2011 Versant Corporation http://www.versant.com
db4o is free software; you can redistribute it and/or modify it under
the terms of version 3 of the GNU General Public License as published
by the Free Software Foundation.
db4o 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 General Public License along
with this program. If not, see http://www.gnu.org/licenses/. */
package com.db4o.foundation;
/**
* Basic functionality for implementing iterators for
* fixed length structures whose elements can be efficiently
* accessed by a numeric index.
*/
public abstract class IndexedIterator implements Iterator4 {
private final int _length;
private int _next;
public IndexedIterator(int length) {
_length = length;
_next = -1;
}
public boolean moveNext() {
if (_next < lastIndex()) {
++_next;
return true;
}
// force exception on unexpected call to current
_next = _length;
return false;
}
public Object current() {
return get(_next);
}
public void reset() {
_next = -1;
}
protected abstract Object get(final int index);
private int lastIndex() {
return _length - 1;
}
}