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Diffstat (limited to 'altoslib/AltosMapCache.java')
| -rw-r--r-- | altoslib/AltosMapCache.java | 207 |
1 files changed, 207 insertions, 0 deletions
diff --git a/altoslib/AltosMapCache.java b/altoslib/AltosMapCache.java new file mode 100644 index 00000000..f0ad433c --- /dev/null +++ b/altoslib/AltosMapCache.java @@ -0,0 +1,207 @@ +/* + * Copyright © 2010 Anthony Towns <aj@erisian.com.au> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + */ + +package org.altusmetrum.altoslib_8; + +import java.io.*; +import java.net.*; + +public class AltosMapCache implements AltosMapCacheListener { + + /* An entry in the MapCache */ + class MapCacheElement implements AltosMapStoreListener { + + AltosMapTile tile; /* Notify when image has been loaded */ + AltosImage image; + AltosMapStore store; + long used; + + class loader implements Runnable { + public void run() { + if (image != null) + tile.notify_image(image); + try { + image = map_interface.load_image(store.file); + } catch (Exception ex) { + } + if (image == null) + tile.set_status(AltosMapTile.failed); + else + tile.set_status(AltosMapTile.success); + tile.notify_image(image); + } + } + + private void load() { + loader l = new loader(); + Thread lt = new Thread(l); + lt.start(); + } + + public void flush() { + if (image != null) { + image.flush(); + image = null; + } + } + + public boolean has_map() { + return store.status() == AltosMapTile.success; + } + + public synchronized void notify_store(AltosMapStore store, int status) { + switch (status) { + case AltosMapTile.loading: + break; + case AltosMapTile.success: + load(); + break; + default: + tile.set_status(status); + tile.notify_image(null); + } + } + + public MapCacheElement(AltosMapTile tile, AltosMapStore store) throws IOException { + this.tile = tile; + this.image = null; + this.store = store; + this.used = 0; + + int status = store.status(); + switch (status) { + case AltosMapTile.loading: + store.add_listener(this); + break; + case AltosMapTile.success: + load(); + break; + default: + tile.set_status(status); + tile.notify_image(null); + break; + } + } + } + + int min_cache_size; /* configured minimum cache size */ + int cache_size; /* current cache size */ + int requested_cache_size; /* cache size computed by application */ + + private Object fetch_lock = new Object(); + private Object cache_lock = new Object(); + + AltosMapInterface map_interface; + + MapCacheElement[] elements = new MapCacheElement[cache_size]; + + long used; + + public void set_cache_size(int new_size) { + + requested_cache_size = new_size; + + if (new_size < min_cache_size) + new_size = min_cache_size; + + if (new_size == cache_size) + return; + + synchronized(cache_lock) { + MapCacheElement[] new_elements = new MapCacheElement[new_size]; + + for (int i = 0; i < cache_size; i++) { + if (i < new_size) + new_elements[i] = elements[i]; + else if (elements[i] != null) + elements[i].flush(); + } + elements = new_elements; + cache_size = new_size; + } + } + + public AltosImage get(AltosMapTile tile, AltosMapStore store, int width, int height) { + int oldest = -1; + long age = used; + + synchronized(cache_lock) { + MapCacheElement element = null; + for (int i = 0; i < cache_size; i++) { + element = elements[i]; + + if (element == null) { + oldest = i; + break; + } + if (store.equals(element.store)) { + element.used = used++; + return element.image; + } + if (element.used < age) { + oldest = i; + age = element.used; + } + } + + try { + element = new MapCacheElement(tile, store); + element.used = used++; + if (elements[oldest] != null) + elements[oldest].flush(); + + elements[oldest] = element; + + if (element.image == null) + tile.set_status(AltosMapTile.loading); + else + tile.set_status(AltosMapTile.success); + + return element.image; + } catch (IOException e) { + tile.set_status(AltosMapTile.failed); + return null; + } + } + } + + public void map_cache_changed(int map_cache) { + min_cache_size = map_cache; + + set_cache_size(requested_cache_size); + } + + public void dispose() { + AltosPreferences.unregister_map_cache_listener(this); + + for (int i = 0; i < cache_size; i++) { + MapCacheElement element = elements[i]; + + if (element != null) + element.flush(); + } + } + + public AltosMapCache(AltosMapInterface map_interface) { + this.map_interface = map_interface; + min_cache_size = AltosPreferences.map_cache(); + + set_cache_size(0); + + AltosPreferences.register_map_cache_listener(this); + } +} |