Sets the lead selection index, ensuring that values between the anchor and the new lead are either all selected or all deselected. If the value at the anchor index is selected, first clear all the values in the range [anchor, oldLeadIndex], then select all the values in the range [anchor, newLeadIndex], where oldLeadIndex is the old leadIndex and newLeadIndex is the new one.
If the value at the anchor index is not selected, do the same thing in reverse selecting values in the old range and deselecting values in the new one.
Generate a single event for this change and notify all listeners. For the purposes of generating minimal bounds in this event, do the operation in a single pass; that way the first and last index inside the ListSelectionEvent that is broadcast will refer to cells that actually changed value because of this method. If, instead, this operation were done in two steps the effect on the selection state would be the same but two events would be generated and the bounds around the changed values would be wider, including cells that had been first cleared only to later be set.
This method can be used in the mouseDragged
method of a UI class to extend a selection.