/* 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.internal.btree;
import com.db4o.foundation.*;
import com.db4o.internal.*;
/**
* @exclude
*/
public class BTreeIterator implements Iterator4{
private final Transaction _transaction;
private final BTree _bTree;
private BTreePointer _currentPointer;
private boolean _beyondEnd;
public BTreeIterator(Transaction trans, BTree bTree){
_transaction = trans;
_bTree = bTree;
}
public Object current() {
if(_currentPointer == null){
throw new IllegalStateException();
}
return _currentPointer.key();
}
public boolean moveNext() {
if(_beyondEnd){
return false;
}
if(beforeFirst()){
_currentPointer = _bTree.firstPointer(_transaction);
} else {
_currentPointer = _currentPointer.next();
}
_beyondEnd = (_currentPointer == null);
return ! _beyondEnd;
}
private boolean beforeFirst() {
return _currentPointer == null;
}
public void reset() {
throw new UnsupportedOperationException();
}
}