211. Add and Search Word - Data structure design

class WordDictionary {
private class TrieNode {
    public boolean isWord;
    public TrieNode[] children = new TrieNode[26];
}
    private TrieNode root;
    /** Initialize your data structure here. */
    public WordDictionary() {
        root = new TrieNode();
    }

    /** Adds a word into the data structure. */
    public void addWord(String word) {
        TrieNode cur =root;
        for(int i = 0 ; i<word.length();++i){
            if(cur.children[word.charAt(i)-'a']==null){
                cur.children[word.charAt(i)-'a']= new TrieNode();
            }
            cur=cur.children[word.charAt(i)-'a'];
        }
        cur.isWord=true;

    }

    /** Returns if the word is in the data structure. A word could contain the dot character '.' to represent any one letter. */
    public boolean search(String word) {
        return match(root,word,0);

    }
    private boolean match(TrieNode root,String word, int index){
        if(index == word.length()) return  root.isWord;
            if(word.charAt(index)!='.'){
                return root.children[word.charAt(index)-'a']!=null && match(root.children[word.charAt(index)-'a'], word,index+1);
            }else{
                for(int i =0 ; i<26;++i){
                    if(root.children[i]==null) continue;
                    if(match(root.children[i], word,index+1)) return true;
                }
                return false;
            }

    }
}

/**
 * Your WordDictionary object will be instantiated and called as such:
 * WordDictionary obj = new WordDictionary();
 * obj.addWord(word);
 * boolean param_2 = obj.search(word);
 */