package lib

$2$

$8$

$0$

$.$

list;

import lib

$2$

$8$

$0$

$.$

base.BilinearIterator

$2$

$8$

$0$

;

import lib

$2$

$8$

$0$

$.$

exception.BeforeTheStart

$2$

$8$

$0$

Exception;

import lib

$2$

$8$

$0$

$.$

exception.ContainerEmpty

$2$

$8$

$0$

Exception;

$/$

$*$

$*$

$$A LinkedIterator which has functions to move forward and back,

$$and to the first and last items of the list. It keeps track of

$$the current item, and also has functions to determine if it is

$$before the start or after the end of the list.

$*$

$/$

public class BilinkedIterator

$2$

$8$

$0$

$$extends LinkedIterator

$2$

$8$

$0$

$$implements BilinearIterator

$2$

$8$

$0$

$\{$

$$

$/$

$*$

$*$

$$Constructor creates a new iterator for list 'list'.

$$ Analysis : Time

$=$

$$O

$($

$1$

$)$

$$

$$ @param list list to be iterated

$*$

$/$

$$public BilinkedIterator

$2$

$8$

$0$

$($

BilinkedList

$2$

$8$

$0$

$$list

$)$

$$

$\{$

$$ super

$($

list

$)$

;

$$

$\}$

$$

$/$

$*$

$*$

$$Create a new iterator at a specific position in the newList.

$$ Analysis : Time

$=$

$$O

$($

$1$

$)$

$$ @param newList list to be iterated

$$ @param initialPrev the previous node for the initial position

$$ @param initialCur the current node for the initial position

$*$

$/$

$$public BilinkedIterator

$2$

$8$

$0$

$($

BilinkedList

$2$

$8$

$0$

$$newList$,$

$$ LinkedNode

$2$

$8$

$0$

$$initialPrev$,$ LinkedNode

$2$

$8$

$0$

$$initialCur

$)$

$$

$\{$

$$ super

$($

newList

$,$

$$initialPrev$,$ initialCur

$)$

;

$$

$\}$

$$

$$

$/$

$*$

$*$

$$

$*$

$$Move the cursor to the last element in the list.

$$

$*$

$$@precond The list is not empty.

$$

$*$

$/$

$$public void goLast

$($

$)$

$$throws ContainerEmpty

$2$

$8$

$0$

Exception

$$

$\{$

$$

$/$

$/$

$$TODO

$$

$\}$

$$

$/$

$*$

$*$

$$

$*$

$$Move the cursor one element closer to the beginning of the list

$$

$*$

$$@precond

$!$

before

$($

$)$

$-$

$$the cursor cannot already be before the first element.

$$

$*$

$/$

$$public void goBack

$($

$)$

$$throws BeforeTheStart

$2$

$8$

$0$

Exception

$$

$\{$

$$

$/$

$/$

$$TODO

$$

$\}$

$$

$/$

$*$

$*$

$$A shallow clone of this object.

$$

$$Analysis: Time

$=$

$$O

$($

$1$

$)$

$*$

$/$

$$public BilinkedIterator

$2$

$8$

$0$

$$clone

$($

$)$

$$

$\{$

$$ return

$($

BilinkedIterator

$2$

$8$

$0$

$)$

$$super$.$clone

$($

$)$

;

$$

$\}$

$\}$

$$

The BilinkedList

$2$

$8$

$0$

$$and BilinkedIterator

$2$

$8$

$0$

$$classes in lib

$2$

$8$

$0$

$-$

asn

$1$

$$are incomplete. There

are missing method bodies in each class. Each missing method body is tagged with a

$/$

$/$

$$TODO comment. Write code to implement each of these unfinished method.

Implementation Notes

The javadoc headers for each method explain what each method is supposed to do

$3$

$.$

$$Many of the

methods you must implement override methods of the LinkedList

$2$

$8$

$0$

$$superclass$.$

Add your code right into the existing files within the lib

$2$

$8$

$0$

$-$

asn

$1$

$$module$.$

When implementing the methods, consider carefully any special cases that might cause need to update

the cursor position, or ensure that it remains in a valid state.

You are not permitted to modify any existing code in the

$.$

java files given. You may only fill in the

missing method bodies.

please solve the question using the starter file