Question

I’ve been working on this for a long time now and can’t figure out why this wont serialize my data. The game is meant to store the user-typed question and answer when it gets it so the next time the game is opened it will have those questions asked… for example does the animal fly … no … input a question that will help me guess next time … it doesn’t fly.. what is it ? monkey…. ok so next time the game runs … it will ask if it doesn’t fly and if it is a monkey. but the problem is i cant seem to put this together.

If i could get help quickly – i would really appreciate it. Thanks.

//GuessTheAnimal Class-----------------------------------
 import javax.swing.JOptionPane;

import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;


public class GuessTheAnimal implements Serializable
{


public static void main(String[] args)
{
Tree animal = new Tree();
animal.instruction();
animal.play();
animal.writeToFile("treeData.ser");
Tree newAnimal = Tree.readFromFile("treeData.ser");
animal.play();



}

}

 //Tree Class-----------------------------------------
  import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
 import java.io.Serializable;

import javax.swing.JOptionPane;


    public class Tree
//Tree class
 {
private Node root;

//constructor
public Tree()
{   root = new Node();
    root.leftChild = new Node();
    root.rightChild = new Node();
    root.questionText = "Does it live on land?";
    root.leftChild.questionText ="bear";  // left side is Yes, right side is No
    root.rightChild.questionText = "parrot";
}

public void instruction()
{
    JOptionPane.showMessageDialog(null, "Think of an animal, I will try to guess it, answer yes or no");
}


public void play()
{
 Node current = root;
 Node parent = current;
 boolean isLeftChild = true;


 while(true)
 {   parent = current;
     int response = JOptionPane.showConfirmDialog(null,current.questionText );
     //code here for yes
     if (response == JOptionPane.YES_OPTION)
     {
        current = current.leftChild;
        isLeftChild=true;
     }
     //code here for no
     else if (response == JOptionPane.NO_OPTION)
     {
        current = current.rightChild;
        isLeftChild = false;
     }


     if (current.leftChild == null && current.rightChild == null)
     {
         int secondQ = JOptionPane.showConfirmDialog(null, "Is your animal a " + current.questionText + "?");

         if (secondQ == JOptionPane.YES_OPTION) 
         {
           JOptionPane.showMessageDialog(null,"I Guessed your animal!");
           return;
         }
         else if (secondQ == JOptionPane.NO_OPTION)
         {
             Node nodeOne = new Node();
             Node nodeTwo = new Node();

              nodeOne.questionText = JOptionPane.showInputDialog("Write a question that differentiates your animal from the animal I guessed, it would be yes for your animal");

              nodeTwo.questionText = JOptionPane.showInputDialog("What is this animal?");

              nodeOne.rightChild = current;
              nodeOne.leftChild = nodeTwo;

              // parent.leftChild = nodeOne or parent.rightChild = nodeOne
              if(isLeftChild == false)
              {
                  parent.rightChild = nodeOne;
                  System.out.println("right child");
              }
              else
                  {
                  parent.leftChild = nodeOne;
                  System.out.println("left Child");
                  }
              return;




         }


     }

}

}

public void preOrder(Node localRoot)
{
if(localRoot != null)
   {
   System.out.print(localRoot.questionText + " ");
   preOrder(localRoot.leftChild);
   preOrder(localRoot.rightChild);
   }
}

public Node getRoot(){
    return root;
}
public boolean writeToFile(String text) {
    try {
        FileOutputStream fileOut = new FileOutputStream("treeData.ser");
        ObjectOutputStream out = new ObjectOutputStream(fileOut);
        out.writeObject(root);
        out.close();
        fileOut.close();
        return true;
} catch (java.io.IOException e) {
    e.printStackTrace();
    System.out.println("-----problem in writeToFile()--------");
    return false;
}
}

/** @return tree read from file, if successful input, else null */
public static Tree readFromFile(String fileName) {
    try {
    FileInputStream fileIn = new FileInputStream("treeData.ser");
    ObjectInputStream objIn = new ObjectInputStream(fileIn);
    Tree newAnimal = (Tree) objIn.readObject();
    objIn.close();
    fileIn.close();
    return newAnimal;
    }
    catch (Exception e){//Catch exception if any
        e.printStackTrace();
        System.out.println("-----problem in readFromFile()--------");
    }
    return null;
}
}


 //Node Class----------------------------------


 public class Node {
 //Node class
//instance variables
public String questionText;
public Node leftChild;
public Node rightChild;

public void displayText()
{
    System.out.println(questionText);
}


/**
 * @param args
 */
public static void main(String[] args) {
    // TODO Auto-generated method stub

}

  }

Answer 1

You are calling play again on animal, not the instance that you have tried to deserialize.

Tree animal = new Tree();
animal.instruction();
animal.play();
animal.writeToFile("treeData.ser");
Tree newAnimal = Tree.readFromFile("treeData.ser");
///should the following not be newAnimal?
animal.play();