source: osm/applications/editors/josm/plugins/CommandLine/src/CommandLine/History.java@ 25038

/*
 *      History.java
 *      
 *      Copyright 2010 Hind <foxhind@gmail.com>
 *      
 */
 
package CommandLine;

import java.util.LinkedList;

public class History {
        private LinkedList<String> historyList;
        private int maxLen;
        private int num;
        
        public History(int len) {
                num = 0;
                maxLen = len;
                historyList = new LinkedList<String>();
        }
        
        public void addItem(String item) {
                if (!item.equals("")) {
                        String prevItem = historyList.peekFirst();
                        if (prevItem == null) {
                                historyList.addFirst(item);
                        }
                        else {
                                if (!prevItem.equalsIgnoreCase(item))
                                        historyList.addFirst(item);
                        }
                        if (historyList.size() > maxLen) {
                                historyList.removeLast();
                        }
                }
                num = -1;
        }
        
        public String getPrevItem() {
                num += 1;
                if (num >= historyList.size()) {
                        num = historyList.size() - 1;
                }
                if (num < 0) {
                        num = -1;
                        return "";
                }
                return historyList.get(num);
        }
        
        public String getLastItem() {
                if (historyList.size() > 0)
                        return historyList.get(0);
                return "";
        }

        public String getNextItem() {
                num -= 1;
                if (num < 0) {
                        num = -1;
                        return "";
                }
                return historyList.get(num);
        }
}