Trie Insertion, Search & Deletion

Trie.java

package app;

import java.util.ArrayList;
import java.util.Stack;

/**
 * Trie
 */
public class Trie {
    private TrieNode root;

    public Trie() {
        root = new TrieNode();
    }

    public void insert(char[] word) {
        TrieNode traversalPointer = root;
        for (int i = 0; i < word.length; i++) {
            if (traversalPointer.links[this.getIndex(word[i])] == null) {
                traversalPointer.links[this.getIndex(word[i])] = new TrieNode();
            }
            traversalPointer = traversalPointer.links[this.getIndex(word[i])];
        }
        traversalPointer.isCompleteWord = true;
    }

    public boolean delete(char[] word) {
        TrieNode traversalPointer = root;
        Stack<TrieNode> s = new Stack<TrieNode>();
        for (int i = 0; i < word.length; i++) {
            if (traversalPointer == null) {
                return false;
            }
            traversalPointer = traversalPointer.links[this.getIndex(word[i])];
            if (traversalPointer == null) {
                return false;
            } else {
                s.push(traversalPointer);
            }
        }
        if (traversalPointer == null) {
            return false;
        }
        if (traversalPointer.isCompleteWord) {
            TrieNode currentNode = s.pop();
            currentNode.isCompleteWord = false;
            currentNode = null;
            while (!s.isEmpty()) {
                TrieNode tempNode = s.pop();
                if (tempNode.canBeDeleted()) {
                    tempNode = null;
                }
            }
            return true;
        }
        return false;
    }

    /**
     * TODO: Fix This
     */
    public ArrayList<String> printAllWords() {
        return this.root.words(new ArrayList<Character>());
    }

    public boolean containsWord(char[] word) {
        TrieNode traversalPointer = root;
        for (int i = 0; i < word.length; i++) {
            if (traversalPointer == null) {
                return false;
            }
            traversalPointer = traversalPointer.links[this.getIndex(word[i])];
        }
        if (traversalPointer == null) {
            return false;
        }
        if (traversalPointer.isCompleteWord) {
            return true;
        }
        return false;
    }

    private int getIndex(char character) {
        return ((int) character) - 97;
    }
}

TrieNode.java

package app;

import java.util.ArrayList;

/**
 * TrieNode
 */
public class TrieNode {

    public boolean isCompleteWord;
    public TrieNode[] links;

    public static int LINK_COUNT = 26;

    public TrieNode() {
        this.isCompleteWord = false;
        links = new TrieNode[LINK_COUNT];
        for (int i = 0; i < links.length; i++) {
            links[i] = null;
        }
    }

    public boolean canBeDeleted() {
        boolean canBeDeleted = true;
        for (int i = 0; i < links.length; i++) {
            canBeDeleted = (canBeDeleted && (this.links[i] != null));
        }
        return canBeDeleted && (!this.isCompleteWord);
    }

    /**
     * TODO: Fix This
     * 
     * @param wordList
     * @return
     */
    public ArrayList<String> words(ArrayList<Character> wordList) {
        ArrayList<String> words = new ArrayList<String>();

        for (int i = 0; i < this.links.length; i++) {
            if (links[i] != null) {
                wordList.add((char) (i + 97));
                links[i].words(wordList);
            }
        }
        words.add(wordList.toString());
        return words;
    }
}