1-D Cellular Automata

I'm having trouble figuring out SetRule() and PropagateNewGeneration(). SetRule() is suppose to convert a rule from 0-255 to an array of eight booleans. For example, rule #16 (0010000)would yield
rules[0] = false
rules[1] = false
rules[2] = false
rules[3] = false
rules[4] = false
rules[5] = true
rules[6] = false
rules[7] = true
PropagateNewGeneration() uses this_gen and rules[] to create next_gen. next_gen will be two blanks longer than this_gen and will apply the rule that if position 2, 3, and 4 in this_gen is "010" (2) then the the position 3 in next_gen will be 1. (Also, all 1s and other chars to be converted to "*" and all 0s to be converted to " ")

Here's my code:

Code:

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import java.util.Scanner;

public class Foothill
{
  public static void main(String[] args)
  {
      Scanner input = new Scanner(System.in);
      int rule;
      String user_input;
      Automaton aut;

      do
      {
        System.out.print("Enter Rule (0 - 255): ");
        user_input = input.nextLine();
        rule = Integer.parseInt(user_input);

      }
      while (rule < 0 || rule > 255);

      aut = new Automaton
        (rule, "                              *                      "
            + "        ");

      System.out.println("Start");
      aut.ShowResults(50);
      System.out.println("End");
  }
}

class Automaton
{
  public static final int MAX_LENGTH  = 80;
  public static final int MAX_GENS  = 500;
 
  private boolean rules[]; 
  private StringBuffer this_gen;

  public Automaton(int new_rule, String first_gen)
  {
      rules = new boolean[8];
      SetRule(new_rule);
      SetFirstGen(first_gen);
  }
 
  public boolean SetFirstGen(String first_gen)
  {
      StringBuffer sb_first_gen = new StringBuffer(first_gen);
     
      if (sb_first_gen.length() < 3 || sb_first_gen.length() > MAX_LENGTH)
      {
        this_gen = new StringBuffer(" *** ");
        return false;
      }

      for (int k = 0; k < first_gen.length(); k++)
        if (sb_first_gen.charAt(k) != ' ')
            sb_first_gen.setCharAt(k, '*');

      this_gen = new StringBuffer(" ");
      this_gen.append(sb_first_gen);
      this_gen.append(" ");
      return true;
  }
 
  void SetRule(int new_rule)
  {
      int bit_to_examine = new_rule, k;

      for (k=0; k<8; k++)
      {
        if ((bit_to_examine & (2^k)) != 0)
            rules[k] = true;
        else
            rules[k] = false;
      }
  }
     
  public void ShowResults(int num_generations)
  {
      if (num_generations < 1 || num_generations > MAX_GENS )
        num_generations = MAX_GENS;
      for (int k = 0; k < num_generations; k++)
      {
        System.out.println(this_gen);
        PropagateNewGeneration();
      }
  }

  private void PropagateNewGeneration()
  {
      int triplet_val, k;
      String bit_result;
      StringBuffer next_gen = new StringBuffer(" ");
     
      next_gen.append(this_gen);
     
      for (k=0; k < this_gen.length(); k++)
      {
        triplet_val = 0;
        bit_result = "";
        bit_result += this_gen.charAt(k) + this_gen.charAt(k+1) +
            this_gen.charAt(k+2);
        if (bit_result == "***")
            triplet_val = 7;
        else if (bit_result == "** ")
            triplet_val = 6;
        else if (bit_result == "* *")
            triplet_val = 5;
        else if (bit_result == "*  ")
            triplet_val = 4;
        else if (bit_result == " **")
            triplet_val = 3;
        else if (bit_result == " * ")
            triplet_val = 2;
        else if (bit_result == "  *")
            triplet_val = 1;
        else
            triplet_val = 0;
        if (rules[triplet_val] == false)
            next_gen.setCharAt(k+1, ' ');
        if (rules[triplet_val] == true)
            next_gen.setCharAt(k+1, '*');
      }
     
      this_gen = next_gen;
     
      next_gen.append(" "); 
  }
}

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I think you forgot to state what your trouble actually was... also, posting your code within [code] /code] tags would preserve the indentation of your code, making it easy for others, who wish to help you, read it