/**
* @return an iterator over all tuples on this page (calling remove on this iterator throws an
* UnsupportedOperationException) (note that this iterator shouldn't return tuples in empty
* slots!)
*/
public Iterator<Tuple> iterator() {
// hdj
final BitSet bitset = BitSet.valueOf(header);
Iterator<Tuple> it =
new Iterator<Tuple>() {
int currentIndex = -1;
public boolean hasNext() {
if (bitset.nextSetBit(currentIndex + 1) == -1) return false;
else return true;
}
public Tuple next() {
currentIndex = bitset.nextSetBit(currentIndex + 1);
return tuples[currentIndex];
}
public void remove() {
throw new UnsupportedOperationException();
}
};
return it;
}
/** Returns true if associated slot on this page is filled. */
public boolean isSlotUsed(int i) {
// hdj
BitSet bitset = BitSet.valueOf(header);
return bitset.get(i);
}
/** Returns the number of empty slots on this page. */
public int getNumEmptySlots() {
// hdj:!!! use getNumTuples instead of bitset.size() or bitset.length()
BitSet bitset = BitSet.valueOf(header);
return getNumTuples() - bitset.cardinality();
}
