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                 System.out.printf("cache size now %d\n", new_size);
  56
  57                 synchronized(cache_lock) {
  58                         AltosUIMapImage[]       new_images = new AltosUIMapImage[new_size];
  59
  60                         for (int i = 0; i < cache_size; i++) {
  61                                 if (i < new_size)
  62                                         new_images[i] = images[i];
  63                                 else if (images[i] != null)
  64                                         images[i].flush();
  65                         }
  66                         images = new_images;
  67                         cache_size = new_size;
  68                 }
  69         }
  70
  71         public Image get(AltosUIMapTile tile, AltosUIMapStore store, int width, int height) {
  72                 int             oldest = -1;
  73                 long            age = used;
  74
  75                 synchronized(cache_lock) {
  76                         AltosUIMapImage image = null;
  77                         for (int i = 0; i < cache_size; i++) {
  78                                 image = images[i];
  79
  80                                 if (image == null) {
  81                                         oldest = i;
  82                                         break;
  83                                 }
  84                                 if (store.equals(image.store)) {
  85                                         image.used = used++;
  86                                         return image.image;
  87                                 }
  88                                 if (image.used < age) {
  89                                         oldest = i;
  90                                         age = image.used;
  91                                 }
  92                         }
  93
  94                         try {
  95                                 image = new AltosUIMapImage(tile, store);
  96                                 image.used = used++;
  97                                 if (images[oldest] != null) {
  98                                         System.out.printf("drop %s\n", images[oldest].store.file.toString());
  99                                         images[oldest].flush();
 100                                 }
 101
 102                                 System.out.printf("load %s\n", store.file.toString());
 103
 104                                 images[oldest] = image;
 105
 106                                 if (image.image == null)
 107                                         tile.set_status(loading);
 108                                 else
 109                                         tile.set_status(success);
 110
 111                                 return image.image;
 112                         } catch (IOException e) {
 113                                 tile.set_status(failed);
 114                                 return null;
 115                         }
 116                 }
 117         }
 118
 119         public void map_cache_changed(int map_cache) {
 120                 min_cache_size = map_cache;
 121
 122                 set_cache_size(requested_cache_size);
 123         }
 124
 125         public void dispose() {
 126                 AltosUIPreferences.unregister_map_cache_listener(this);
 127
 128                 for (int i = 0; i < cache_size; i++) {
 129                         AltosUIMapImage image = images[i];
 130
 131                         if (image != null)
 132                             image.flush();
 133                 }
 134         }
 135
 136         public AltosUIMapCache() {
 137                 min_cache_size = AltosUIPreferences.map_cache();
 138
 139                 set_cache_size(0);
 140
 141                 AltosUIPreferences.register_map_cache_listener(this);
 142         }
 143 }