/**
* If this Link is not chained to one or more other Links, insert it into a chain after that Link,
* including a chain in which that Link is the only Link. This Link inherits the root of that
* Link. Upon completion, this Link will be part of a chain just after that Link. A reference to
* this Link is returned. If this Link is already chained to other Links, null is returned; you
* must remove this Link from its own chain before inserting it into another chain. An insert is
* done in O(1) time. A Link could be inserted after itself (which would have no effect on its
* state), but null is returned if this is attempted.
*
* @param that refers to a Link that this Link is to be inserted after.
* @return a reference to this Link if the insert was successful, false otherwise.
*/
public Link<Type> insert(Link<Type> that) {
if (!isChained() && (this != that)) {
next = that.next;
previous = that;
root = that.root;
next.previous = this;
that.next = this;
return this;
}
return null;
}
/**
* If this Link is chained to one or more other Links, remove it from that chain. Upon completion,
* this will be a valid unchained Link and the the chain that it was on will be intact without
* this Link. If this Link was the root of a chain of just two Links, the other Link is rooted
* back to itself. If this Link was the root of a chain with more than two Links, the resulting
* chain is left still rooted to this Link, which is unlikely to be what you want. A reference to
* this Link is returned. If this Link is not chained to other Links, null is returned. A remove
* is done in O(1) time.
*
* @return a reference to this Link if the remove was successful, false otherwise.
*/
public Link<Type> remove() {
if (isChained()) {
next.previous = previous;
if (next.previous == next) {
next.root = next;
}
previous.next = next;
if (previous.next == previous) {
previous.root = previous;
}
next = this;
previous = this;
root = this;
return this;
}
return null;
}