/**
* Adjust any cursors that are referring to this BIN. This method is called during a split
* operation. "this" is the BIN being split. newSibling is the new BIN into which the entries from
* "this" between newSiblingLow and newSiblingHigh have been copied.
*
* @param newSibling - the newSibling into which "this" has been split.
* @param newSiblingLow, newSiblingHigh - the low and high entry of "this" that were moved into
* newSibling.
*/
@Override
void adjustCursors(IN newSibling, int newSiblingLow, int newSiblingHigh) {
assert newSibling.isLatchOwnerForWrite();
assert this.isLatchOwnerForWrite();
int adjustmentDelta = (newSiblingHigh - newSiblingLow);
Iterator<CursorImpl> iter = cursorSet.iterator();
while (iter.hasNext()) {
CursorImpl cursor = iter.next();
if (getCursorBINToBeRemoved(cursor) == this) {
/*
* This BIN will be removed from the cursor by CursorImpl
* following advance to next BIN; ignore it.
*/
continue;
}
int cIdx = getCursorIndex(cursor);
BIN cBin = getCursorBIN(cursor);
assert cBin == this : "nodeId=" + getNodeId() + " cursor=" + cursor.dumpToString(true);
assert newSibling instanceof BIN;
/*
* There are four cases to consider for cursor adjustments,
* depending on (1) how the existing node gets split, and (2) where
* the cursor points to currently. In cases 1 and 2, the id key of
* the node being split is to the right of the splitindex so the
* new sibling gets the node entries to the left of that index.
* This is indicated by "new sibling" to the left of the vertical
* split line below. The right side of the node contains entries
* that will remain in the existing node (although they've been
* shifted to the left). The vertical bar (^) indicates where the
* cursor currently points.
*
* case 1:
*
* We need to set the cursor's "bin" reference to point at the
* new sibling, but we don't need to adjust its index since that
* continues to be correct post-split.
*
* +=======================================+
* | new sibling | existing node |
* +=======================================+
* cursor ^
*
* case 2:
*
* We only need to adjust the cursor's index since it continues
* to point to the current BIN post-split.
*
* +=======================================+
* | new sibling | existing node |
* +=======================================+
* cursor ^
*
* case 3:
*
* Do nothing. The cursor continues to point at the correct BIN
* and index.
*
* +=======================================+
* | existing Node | new sibling |
* +=======================================+
* cursor ^
*
* case 4:
*
* Adjust the "bin" pointer to point at the new sibling BIN and
* also adjust the index.
*
* +=======================================+
* | existing Node | new sibling |
* +=======================================+
* cursor ^
*/
BIN ns = (BIN) newSibling;
if (newSiblingLow == 0) {
if (cIdx < newSiblingHigh) {
/* case 1 */
setCursorBIN(cursor, ns);
iter.remove();
ns.addCursor(cursor);
} else {
/* case 2 */
setCursorIndex(cursor, cIdx - adjustmentDelta);
}
} else {
if (cIdx >= newSiblingLow) {
/* case 4 */
setCursorIndex(cursor, cIdx - newSiblingLow);
setCursorBIN(cursor, ns);
iter.remove();
ns.addCursor(cursor);
}
}
}
}
