/*
* This method takes two elements and exchanges their parents and previous
* elements. It then makes sure spacing is correct by calling
* focusPositionAndLines
*
* This method assumes index1 < index2
*/
private synchronized void swapElements(Object newParam, int index1, int index2) {
// the two elements to be swapped
LinearElement firstElement = root.getVector().get(index1);
LinearElement secondElement = root.getVector().get(index2);
// the two elements after each of the elements to be swapped
LinearElement secondElementNext;
LinearElement firstElementNext;
/*
* There is a corner case where secondElement.previousChild is
* firstElement
*/
// the first element's previous child before it is reassigned
LinearElement tempPrevChild = firstElement.getPreviousChild();
if (index2 != index1 + 1) { // the elements are not adjacent
// set previous elements for the two nodes
firstElement.setPreviousChild(secondElement.getPreviousChild());
secondElement.setPreviousChild(tempPrevChild);
// set previous elements for the nodes referencing the swapped nodes
if (index1 + 1 < root.getVector().size()) {
firstElementNext = root.getVector().get(index1 + 1);
firstElementNext.setPreviousChild(secondElement);
}
if (index2 + 1 < root.getVector().size()) {
secondElementNext = root.getVector().get(index2 + 1);
secondElementNext.setPreviousChild(firstElement);
}
} else { // the elements are adjacent
firstElement.setPreviousChild(secondElement);
secondElement.setPreviousChild(tempPrevChild);
// set previous elements for the nodes referencing the second node
if (index2 + 1 < root.getVector().size()) {
secondElementNext = root.getVector().get(index2 + 1);
secondElementNext.setPreviousChild(firstElement);
}
}
// swap the elements in root
root.getVector().swap(index1, index2);
root.focusPosition();
}
