Please help me to implement these methods, I already finished the reset and isWord, and I attach the screenshot of the interface. The size for this project is measure how many words can be formed using this letter as the prefix.

import java.util.ArrayList;

$$public class AutoComplete implements AutoCompleteInterface $\{$

$$ private DLBNode root; $//$root of the DLB Trie

$$ private StringBuilder currentPrefix; $//$running prefix

$$ private DLBNode currentNode; $//$current DLBNode

$//$TODO: Add more instance variables as needed

$$ public AutoComplete$()\{$

$$ this.root $=$ null;

$$ this.currentPrefix $=$ new StringBuilder$()$;

$$ this.currentNode $=$ null;

$$ this.counter $=0$;

$\}$

$$ @Override

$$ public boolean add$($String word$)\{$

$//$ TODO Auto$-$generated method stub

$$

$\}$

$$ @Override

$$ public boolean advance$($char c$)\{$

$//$ TODO Auto$-$generated method stub

$\}$

$$ @Override

$$ public void retreat$()\{$

$//$ TODO Auto$-$generated method stub

$\}$

$$ @Override

$$ public void reset$()\{$

$//$ TODO Auto$-$generated method stub

$$ currentPrefix.setLength$(0)$;

$$ currentNode $=$ null;

$\}$

$$ @Override

$$ public boolean isWord$()\{$

$$ return currentNode $!=$ null && currentNode.isWord;

$\}$

$$ @Override

$$ public void add$()\{$

$//$ TODO Auto$-$generated method stub

$$

$\}$

$$ @Override

$$ public int getNumberOfPredictions$()\{$

$//$ TODO Auto$-$generated method stub

$$ if $($currentNode $==$ null$)\{$

$$ return $0$;

$\}$

$$ return currentNode.size;

$\}$

$$ @Override

$$ public String retrievePrediction$()\{$

$//$ TODO Auto$-$generated method stub

$$

$\}$

$$ @Override

$$ public ArrayList retrievePredictions$()\{$

$//$ TODO Auto$-$generated method stub

$$

$\}$

$$

$$ private void collect$($DLBNode x$,$ ArrayList arr, StringBuilder scout$)\{$

$//$ TODO Auto$-$generated method stub

$\}$

$$ @Override

$$ public boolean delete$($String word$)\{$

$//$ TODO Auto$-$generated method stub

$$ throw new UnsupportedOperationException$("$Unimplemented method 'delete'"$)$;

$\}$

$//$The DLBNode class

$$ private class DLBNode$\{$

$$ private char data; $//$letter inside the node

$$ private int size;$//$number of words in the subtrie rooted at node

$$ private boolean isWord; $//$true if the node is at the end of a word

$$ private DLBNode nextSibling; $//$doubly$-$linked list of siblings

$$ private DLBNode previousSibling;

$$ private DLBNode child; $//$ child reference

$$ private DLBNode parent; $//$parent reference

$$ private DLBNode$($char data$)\{//$constructor

$$ this.data $=$ data;

$$ size $=0$;

$$ isWord $=$ false;

$\}$

$\}$

$```$

$*$ Adds a word to the dictionary in O$($alphabet size$*$word$.$length$())$ time

$*$ @param word the String to be added to the dictionary

$*$ @return true if add is successful, false if word already exists

$*$ @throws IllegalArgumentException if word is the empty string or null

$*/$

public boolean add$($String word$)$;

$/**$

$*$ Appends a character to the running prefix in O$($alphabet size$)$ time.

$*$ This method doesn't modify the dictionary.

$*$ @param c: the character to append

$*$ @return true if the running prefix after appending c is a prefix to a word

$*$ in the dictionary and false otherwise

$*/$

public boolean advance$($char c$)$;

$/**$

$*$ Removes the last character from the running prefix in O$($alphabet size$)$

$*$ time. This method doesn't modify the dictionary.

$*$ @throws IllegalStateException if the running prefix is the empty string

$*/$

public void retreat$()$;

$/**$

$*$ Resets the current prefix to the empty string in O$(1)$ time

$*/$

public void reset$()$;

$/**$

$*$ Checks if the running prefix is a word in the dictionary in $0(1)$ time.

$*$ @return true if the running prefix is a word in the dictionary and false

$*$ otherwise.

$*/$

public boolean isWord$()$;

$``````$

$/**$

$*$ Adds the running prefix as a word to the dictionary $($if not already a word$)$

$*$ The running time is $0($alphabet size$*$length of the running prefix$).$

$*/$

public void add$()$;

$/**$

$*$ Retrieves the number of dictionary words that start with the running prefix in $0(1)$ time.

$*$ @return the number of dictionary words that start with the running

$*$ prefix $($including the running prefix if it is a word$).$

$*/$

$8$ public int getNumberOfPredictions$()$;

$/**$

$*$ Retrieves one dictionary word that starts with the running prefix. The running time is

$*$ O$($length of the returned word$)$

$*$ @return a String or null if no predictions exist for the running prefix

$*/$

public String retrievePrediction$()$;

$/**$

$*$ Retrieves a lexicographically sorted list of all dictionary words that start with the running

$*$ O$($length of the returned words$)$

$*$ @return an ArrayList of sorted word predictions or null if no predictions exist for t

$*/$

public ArrayList retrievePredictions$()$;

$/**$

$*$ EXTRA CREDIT: Deletes a word from the dictionary in O$($alphabet size$*$word$.$length$())$ time.

$*$ @param word the String to be deleted from the dictionary

$*$ @return true if delete is successful, false if word doesn't exist

$*$ @throws IllegalArgumentException if word is the empty s