@Override
public boolean deleteAtPosition(int position) {
// TODO Auto-generated method stub
if (position == 0) {
return deleteFront();
}
if (position == this.length() - 1) {
return deleteBack();
}
if (this.head == null && this.tail == null) return false;
else {
if (head.getNext() == null) {
head = null;
tail = null;
return true;
} else {
Node current = this.head;
Node previous = this.head;
int counter = 0;
while (current.getNext() != null) {
if (counter == position) {
previous.setNext(current.getNext());
current.getNext().setPrev(previous);
return true;
}
previous = current;
current = current.getNext();
counter++;
}
return false;
}
}
}
@Override
public boolean deleteFront() {
// TODO Auto-generated method stub
if (this.head == null && this.tail == null) return false;
else {
if (head.getNext() == null) {
head = null;
tail = null;
return true;
} else {
head = head.getNext();
this.head.setPrev(null);
return true;
}
}
}
@Override
public void addAtPosition(Object data, int position) {
// TODO Auto-generated method stub
if (position == 0) {
addFront(data);
return;
}
if (position >= this.length()) {
addBack(data);
return;
}
Node newNode = new Node(data);
if (this.head == null && this.tail == null) {
this.head = newNode;
this.tail = newNode;
} else {
Node current = this.head;
Node previous = this.head;
int counter = 0;
while (current != null) {
if (counter == position) {
previous.setNext(newNode);
newNode.setPrev(previous);
newNode.setNext(current);
current.setPrev(newNode);
break;
}
previous = current;
current = current.getNext();
counter++;
}
}
}
@Override
public Node get(String dataIn) {
// TODO Auto-generated method stub
if (this.head == null) return null;
else {
Node current = this.head;
while (current != null) {
if (dataIn == current.getData().toString()) return current;
current = current.getNext();
}
return null;
}
}
@Override
public boolean deleteBack() {
// TODO Auto-generated method stub
if (this.head == null) return false;
else {
if (head.getNext() == null && this.tail == null) {
head = null;
tail = null;
return true;
} else {
Node current = this.head;
while (current.getNext() != null) {
if (current.getNext().getNext() == null) {
current.getNext().setPrev(null);
current.setNext(null);
this.tail = current;
return true;
}
current = current.getNext();
}
return false;
}
}
}
@Override
public Node getAtPosition(int position) {
// TODO Auto-generated method stub
if (position == 0) return getFront();
if (position == this.length() - 1) return getBack();
if (this.head == null) return null;
else {
Node current = this.head;
int counter = 0;
while (current != null) {
if (counter == position) return current;
current = current.getNext();
}
return null;
}
}