package org.kuali.rice.krms.util;
   
   import java.io.Serializable;
   import java.util.ArrayList;
   import java.util.Iterator;
   import java.util.List;
   
   /**
    * Created with IntelliJ IDEA.
   * User: SW
   * Date: 2013/02/12
   * Time: 12:15 PM
   * To change this template use File | Settings | File Templates.
   */
  public class AlphaIterator implements Serializable, Iterator {
  
      private List<Inner> list = new ArrayList<Inner>();
  
      @Override
      public boolean hasNext() {
          return true;
      }
  
      @Override
      public Object next() {
  
          //Add an initial value to the list
          if (list.isEmpty()) {
              list.add(new Inner());
          } else {
  
              //Increment the value
              for (int i = list.size() - 1; i >= 0; i--) {
                  Inner in = list.get(i);
                  if (in.increment()>0) {
                      break;
                  } else {
                      in.reset();
                      if (i == 0) {
                          list.add(new Inner());
                      }
                  }
              }
          }
  
          //Create the return string
          String returnValue = "";
          for (Inner in : list) {
              returnValue = returnValue + (char)in.current();
          }
  
          return returnValue;
      }
  
      @Override
      public void remove() {
          //To change body of implemented methods use File | Settings | File Templates.
      }
  
      private class Inner {
  
          private final static int START = 'A';
          private final static int END = 'Z';
  
          private int value;
  
          public Inner() {
              value = START;
          }
  
          public void reset() {
              value = START;
          }
  
          public int current() {
              return value;
          }
  
          public int increment() {
              if (value == END) {
                  return -1;
              } else {
                  return value++;
              }
          }
  
      }
  }