TreeNode implementation for the Twenty Questions tutorial on the SSaurel's Channel

TreeNode.java

package com.ssaurel.twentyquestions;

// We will use a Binary Tree to represent the questions 
// for guessing what user thinks about
// So we need to represent tree nodes
public class TreeNode {

  enum Type {
    ANSWER, QUESTION // nodes are answer or question
  }

  public static final String QUESTION_FLAG = "Q:";
  public static final String ANSWER_FLAG = "A:";
  public String data;
  public Type type;
  // if tree node is a question, he has two children (one for yes, one for no)
  public TreeNode yes;
  public TreeNode no; 

  public TreeNode() {
  }

  public TreeNode(String data, Type type) {
    this.data = data;
    this.type = type;
  }

  public boolean isQuestion() {
    return Type.QUESTION.equals(type);
  }

  public void setData(String data) {
    type = Type.QUESTION;

    if (data.startsWith(ANSWER_FLAG)) {
      type = Type.ANSWER;
    }

    this.data = data.substring(2); // we remove question or answer flag
  }

  public void addYes(TreeNode yes) {
    this.yes = yes;
  }

  public void addNo(TreeNode no) {
    this.no = no;
  }

}