input textb4StringReader(textB)nextLine

input textb4
StringReader(textB)
nextLine getNexLine;
currentSeq = decodeLine (nextLine)
if not isSequenceTag(currentSeq)
abort 'syntax error'
end if
currentSequence (id, level, order, occur) // occ , order, and level are init to 1
Loop over StringReader(textB) until nextline=null
  BaseTag = decocdeLine(nextLine)
  if isSequenceTag(baseTag)
   newSeq = baseTag
    // new Subsequence, new Sequence, end sequence
  else if isSimpleTag(baseTag)
   newTag = baseTag
  else // null
   currenTag.append text
  end if

http://www.dba-oracle.com/concepts/rule_based_optimizer.htm
http://www.devx.com/gethelpon/10MinuteSolution/16596/0/

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StringReader;

public class Test {
public static void main(String[] args) {
  String s= "X1hhhhahhha" +"\r\n";
  s= s + "a1hhhhahhha" +"\r\n";
  s=s+ "X2hhhhahhha" +"\r\n";
  s= s + "a2hhhhahhha" +"\r\n";
  s=s+ "X3hhhhahhha" +"\r\n";
  s= s + "a3hhhhahhha" +"\r\n";
  s=s+ "X4hhhhahhha" +"\r\n";
  s= s + "a4hhhhahhha" +"\r\n";
  s=s+ "X5hhhhahhha" +"\r\n";
  s= s + "a5hhhhahhha" +"\r\n";
  try {
   new Test().treat(s);
  } catch (Exception e) {
   // TODO: handle exception
   e.printStackTrace();
  }
 
}
private void treat(String s)throws IOException{
  StringReader sR = new StringReader(s);
  BufferedReader bR = new BufferedReader(sR);
  decodeX(bR);
  System.out.println("End Treat");
   
 
 
 
}

private void decodeX(BufferedReader bR)throws IOException{
 
  String nextLine = bR.readLine();
 
  while (nextLine!=null){
   if (nextLine.substring(0, 1).equals("X")) {
    System.out.println(nextLine);
    decodeX(bR);
   
   }else{
    System.out.println(nextLine);
   }
   
   
     if (bR.ready()){
      System.out.println("ready");
      nextLine = bR.readLine();
      
     }else{
      System.out.println("not ready");
     }
   
  }
 
  System.out.println("End DecodeX");
 
}
}

  return tagObject or seq Object. tag and seq inherit from iTag
   or
  return null
  when retun null must add the it to the tag by append