source/ch/cyberduck/core/Navigation.java

   1 package ch.cyberduck.core;
   2
   3 /*
   4  *  Copyright (c) 2013 David Kocher. All rights reserved.
   5  *  http://cyberduck.ch/
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  Bug fixes, suggestions and comments should be sent to:
  18  *  dkocher@cyberduck.ch
  19  */
  20
  21 import java.util.List;
  22
  23 /**
  24  * @version $Id:$
  25  */
  26 public class Navigation {
  27
  28     /**
  29      * Keeps a ordered backward history of previously visited paths
  30      */
  31     private List<Path> back = new Collection<Path>();
  32
  33     /**
  34      * Keeps a ordered forward history of previously visited paths
  35      */
  36     private List<Path> forward = new Collection<Path>();
  37
  38     /**
  39      * @param p Directory
  40      */
  41     public void add(final Path p) {
  42         if(back.size() > 0) {
  43             // Do not add if this was a reload
  44             if(p.equals(back.get(back.size() - 1))) {
  45                 return;
  46             }
  47         }
  48         back.add(p);
  49     }
  50
  51     /**
  52      * Returns the prevously browsed path and moves it to the forward history
  53      *
  54      * @return The previously browsed path or null if there is none
  55      */
  56     public Path back() {
  57         int size = back.size();
  58         if(size > 1) {
  59             forward.add(back.get(size - 1));
  60             Path p = back.get(size - 2);
  61             //delete the fetched path - otherwise we produce a loop
  62             back.remove(size - 1);
  63             back.remove(size - 2);
  64             return p;
  65         }
  66         else if(1 == size) {
  67             forward.add(back.get(size - 1));
  68             return back.get(size - 1);
  69         }
  70         return null;
  71     }
  72
  73     /**
  74      * @return The last path browsed before #back was called
  75      * @see #back()
  76      */
  77     public Path forward() {
  78         int size = forward.size();
  79         if(size > 0) {
  80             Path p = forward.get(size - 1);
  81             forward.remove(size - 1);
  82             return p;
  83         }
  84         return null;
  85     }
  86
  87     /**
  88      * @return The ordered array of previously visited directories
  89      */
  90     public List<Path> getBack() {
  91         return back;
  92     }
  93
  94     /**
  95      * @return The ordered array of previously visited directories
  96      */
  97     public List<Path> getForward() {
  98         return forward;
  99     }
 100
 101     public void clear() {
 102         back.clear();
 103         forward.clear();
 104     }
 105 }