git.gag.com Git - fw/altos/blob - altosuilib/AltosUIMapCache.java

   1 /*
   2  * Copyright © 2010 Anthony Towns <aj@erisian.com.au>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 package org.altusmetrum.altosuilib_3;
  19
  20 import javax.swing.*;
  21 import javax.imageio.ImageIO;
  22 import java.awt.image.*;
  23 import java.awt.*;
  24 import java.io.*;
  25 import java.net.*;
  26
  27 public class AltosUIMapCache implements AltosUIMapCacheListener {
  28         static final int        success = 0;
  29         static final int        loading = 1;
  30         static final int        failed = 2;
  31         static final int        bad_request = 3;
  32         static final int        forbidden = 4;
  33
  34         int                     min_cache_size;         /* configured minimum cache size */
  35         int                     cache_size;             /* current cache size */
  36         int                     requested_cache_size;   /* cache size computed by application */
  37
  38         private Object          fetch_lock = new Object();
  39         private Object          cache_lock = new Object();
  40
  41         AltosUIMapImage[]       images = new AltosUIMapImage[cache_size];
  42
  43         long                    used;
  44
  45         public void set_cache_size(int new_size) {
  46
  47                 requested_cache_size = new_size;
  48
  49                 if (new_size < min_cache_size)
  50                         new_size = min_cache_size;
  51
  52                 if (new_size == cache_size)
  53                         return;
  54
  55                 synchronized(cache_lock) {
  56                         AltosUIMapImage[]       new_images = new AltosUIMapImage[new_size];
  57
  58                         for (int i = 0; i < cache_size; i++) {
  59                                 if (i < new_size)
  60                                         new_images[i] = images[i];
  61                                 else if (images[i] != null)
  62                                         images[i].flush();
  63                         }
  64                         images = new_images;
  65                         cache_size = new_size;
  66                 }
  67         }
  68
  69         public Image get(AltosUIMapTile tile, AltosUIMapStore store, int width, int height) {
  70                 int             oldest = -1;
  71                 long            age = used;
  72
  73                 synchronized(cache_lock) {
  74                         AltosUIMapImage image = null;
  75                         for (int i = 0; i < cache_size; i++) {
  76                                 image = images[i];
  77
  78                                 if (image == null) {
  79                                         oldest = i;
  80                                         break;
  81                                 }
  82                                 if (store.equals(image.store)) {
  83                                         image.used = used++;
  84                                         return image.image;
  85                                 }
  86                                 if (image.used < age) {
  87                                         oldest = i;
  88                                         age = image.used;
  89                                 }
  90                         }
  91
  92                         try {
  93                                 image = new AltosUIMapImage(tile, store);
  94                                 image.used = used++;
  95                                 if (images[oldest] != null)
  96                                         images[oldest].flush();
  97
  98                                 images[oldest] = image;
  99
 100                                 if (image.image == null)
 101                                         tile.set_status(loading);
 102                                 else
 103                                         tile.set_status(success);
 104
 105                                 return image.image;
 106                         } catch (IOException e) {
 107                                 tile.set_status(failed);
 108                                 return null;
 109                         }
 110                 }
 111         }
 112
 113         public void map_cache_changed(int map_cache) {
 114                 min_cache_size = map_cache;
 115
 116                 set_cache_size(requested_cache_size);
 117         }
 118
 119         public void dispose() {
 120                 AltosUIPreferences.unregister_map_cache_listener(this);
 121
 122                 for (int i = 0; i < cache_size; i++) {
 123                         AltosUIMapImage image = images[i];
 124
 125                         if (image != null)
 126                             image.flush();
 127                 }
 128         }
 129
 130         public AltosUIMapCache() {
 131                 min_cache_size = AltosUIPreferences.map_cache();
 132
 133                 set_cache_size(0);
 134
 135                 AltosUIPreferences.register_map_cache_listener(this);
 136         }
 137 }