/**
* Deletes a point from a given index.
*
* @param index the index
* @return true, if successful
*/
public boolean deleteIndex(int index) {
if (index == 0) {
if (size == 1) {
clearList();
return true;
}
start = start.getNext();
start.setPrev(end);
end.setNext(start);
size--;
return true;
}
if (index == (size - 1)) {
end = end.getPrev();
end.setNext(start);
start.setPrev(end);
size--;
return true;
}
PointElement pointer = start.getNext();
for (int i = 1; i < size; i++) {
if (i == index) {
PointElement previousElement = pointer.getPrev();
PointElement nextElement = pointer.getNext();
previousElement.setNext(nextElement);
nextElement.setPrev(previousElement);
size--;
return true;
}
pointer = pointer.getNext();
}
return false;
}
/**
* Insert point at the end of the list.
*
* @param point the point
*/
public void insertEnd(Point point) {
PointElement newElement = new PointElement(point, null, null);
if (start == null) {
startNotInitialized(newElement);
} else {
newElement.setPrev(end);
end.setNext(newElement);
start.setPrev(newElement);
newElement.setNext(start);
end = newElement;
}
size++;
}
/**
* Insert a point at a given index.
*
* @param point the point
* @param index the index
*/
public void insertIndex(Point point, int index) {
PointElement newElement = new PointElement(point, null, null);
if (index == 0) {
insertStart(point);
return;
}
PointElement pointer = start;
for (int i = 1; i <= size; i++) {
if (i == index) {
PointElement nextElement = pointer.getNext();
pointer.setNext(newElement);
newElement.setPrev(pointer);
newElement.setNext(nextElement);
nextElement.setPrev(newElement);
}
pointer = pointer.getNext();
}
size++;
}
/**
* This method is a help method and is invoked when the list is still empty.
*
* @param newElement the new element
*/
private void startNotInitialized(PointElement newElement) {
newElement.setNext(newElement);
newElement.setPrev(newElement);
start = newElement;
end = start;
}
