001    package org.kuali.rice.krms.util;
002    
003    import java.io.Serializable;
004    import java.util.ArrayList;
005    import java.util.Iterator;
006    import java.util.List;
007    
008    /**
009     * Created with IntelliJ IDEA.
010     * User: SW
011     * Date: 2013/02/12
012     * Time: 12:15 PM
013     * To change this template use File | Settings | File Templates.
014     */
015    public class AlphaIterator implements Serializable, Iterator {
016    
017        private List<Inner> list = new ArrayList<Inner>();
018    
019        @Override
020        public boolean hasNext() {
021            return true;
022        }
023    
024        @Override
025        public Object next() {
026    
027            //Add an initial value to the list
028            if (list.isEmpty()) {
029                list.add(new Inner());
030            } else {
031    
032                //Increment the value
033                for (int i = list.size() - 1; i >= 0; i--) {
034                    Inner in = list.get(i);
035                    if (in.increment()>0) {
036                        break;
037                    } else {
038                        in.reset();
039                        if (i == 0) {
040                            list.add(new Inner());
041                        }
042                    }
043                }
044            }
045    
046            //Create the return string
047            String returnValue = "";
048            for (Inner in : list) {
049                returnValue = returnValue + (char)in.current();
050            }
051    
052            return returnValue;
053        }
054    
055        @Override
056        public void remove() {
057            //To change body of implemented methods use File | Settings | File Templates.
058        }
059    
060        private class Inner {
061    
062            private final static int START = 'A';
063            private final static int END = 'Z';
064    
065            private int value;
066    
067            public Inner() {
068                value = START;
069            }
070    
071            public void reset() {
072                value = START;
073            }
074    
075            public int current() {
076                return value;
077            }
078    
079            public int increment() {
080                if (value == END) {
081                    return -1;
082                } else {
083                    return value++;
084                }
085            }
086    
087        }
088    }