public LinkedList prepend(LinkedList r) {
r.prev = this.prev;
r.next = this;
if (this.prev != null) this.prev.next = r;
this.prev = r;
return r;
}
public LinkedList insert(LinkedList r) {
r.prev = this;
r.next = this.next;
if (this.next != null) this.next.prev = r;
this.next = r;
return r;
}
public LinkedList append(LinkedList r) {
LinkedList p = this;
r.next = null;
while (p.next != null) p = p.next;
p.next = r;
return (r.prev = p);
}
public static LinkedList reverseQueue(LinkedList head) {
LinkedList current = head;
if (current == null) {
return null;
}
LinkedList next = current.next;
if (next == null) {
head = current;
return head;
}
head = reverseQueue(next);
next.next = current;
current.prev = next;
next.prev = null;
current.next = null;
return head;
}
public LinkedList detach() { // returns new head relative to this node
LinkedList p = prev, n = next;
if (this == first()) {
if (n != null) n.prev = null;
next = null;
return n;
}
if (this == last()) {
if (p != null) p.next = null;
prev = null;
return p;
}
prev = null;
next = null;
// if (p == null && n == null) return null;
if (p != null) p.next = n;
if (n != null) n.prev = p;
if (p == null) return n;
else return p.first();
}
public void eraseList() {
LinkedList t;
LinkedList f = first();
t = f.next;
f.next = null; // remove references
while (t != null) {
f = t.next;
t.prev = null;
t.next = null;
t = f;
}
;
}
public LinkedList cloneList() {
LinkedList t;
LinkedList f = first();
LinkedList k = (LinkedList) f.clone();
LinkedList nf = k;
while (f.hasMoreElements() != false) {
f = (LinkedList) f.nextElement();
t = (LinkedList) f.clone();
t.prev = k;
k.next = t;
k = t;
}
;
return nf;
}
public LinkedList allBut(Object key) {
LinkedList t;
LinkedList f = first();
if (f.value.equals(key))
if (f.next != null) f = f.next;
else return null;
LinkedList k = (LinkedList) f.clone();
LinkedList nf = k;
while (f.hasMoreElements() != false) {
f = (LinkedList) f.nextElement();
if (f.value.equals(key)) continue;
t = (LinkedList) f.clone();
t.prev = k;
k.next = t;
k = t;
}
;
return nf;
}