public boolean hasNext() throws DbException, TransactionAbortedException, IOException {
// System.out.println("hf has next: " + _currentPageId +_numPages);
if (_tupleIterator == null) return false;
if (_tupleIterator.hasNext()) return true;
// If we have more pages
// System.out.println(_currentPageId+" llllll "+_numPages);
while (_currentPageId < (_numPages)) {
_currentPage = readPage(_currentPageId++);
_tupleIterator = _currentPage.iterator();
if (_tupleIterator.hasNext()) {
_pagesRead++;
return true;
}
}
return false;
}
public Tuple previous() throws DbException, TransactionAbortedException, IOException {
// System.out.println("previous ");
if (_tupleIterator == null) {
throw new NoSuchElementException("Tuple iterator not opened");
}
if (((HeapPageIterator) _tupleIterator).hasPrevious()) {
return ((HeapPageIterator) _tupleIterator).previous();
} else {
if (_currentPageId > 1) {
// System.out.println("CUURENT PAGEID "+_currentPageId);
_currentPageId = _currentPageId - 2;
_currentPage = readPage(_currentPageId++);
// System.out.println("NOW "+_currentPageId);
_pagesRead++;
_tupleIterator = _currentPage.iterator();
((HeapPageIterator) _tupleIterator).setLast();
if (((HeapPageIterator) _tupleIterator).hasPrevious()) {
return ((HeapPageIterator) _tupleIterator).previous();
}
} else return null;
}
return null;
}
public void open() throws DbException, TransactionAbortedException, IOException {
_currentPage = readPage(_currentPageId++);
_pagesRead++;
_tupleIterator = _currentPage.iterator();
}