The configuration might look like the following: * *
* arrows.path = /rsrc/media/icons/arrows.png * arrows.metrics = 20, 25 # icons that are 20 pixels wide and 25 pixels tall * * smileys.path = /rsrc/media/icons/smileys.png * smileys.metrics = 16, 16 # icons that are 16 pixels square ** * A user could then request an
arrows icon like so:
*
*
* Icon icon = iconmgr.getIcon("arrows", 2);
*
*/
public class IconManager
{
/**
* Creates an icon manager that will obtain tilesets from the supplied
* tile manager and which will load its configuration information from
* the specified properties file.
*
* @param tmgr the tile manager to use when fetching tilesets.
* @param configPath the path (relative to the classpath) from which
* the icon manager configuration can be loaded.
*
* @exception IOException thrown if an error occurs loading the
* configuration file.
*/
public IconManager (TileManager tmgr, String configPath)
throws IOException
{
this(tmgr, ConfigUtil.loadProperties(configPath));
}
/**
* Creates an icon manager that will obtain tilesets from the supplied
* tile manager and which will read its configuration information from
* the supplied properties file.
*/
public IconManager (TileManager tmgr, Properties config)
{
// save these for later
_tilemgr = tmgr;
_config = config;
}
/**
* If icon images should be loaded from a set of resource bundles
* rather than the classpath, that set can be set here.
*/
public void setSource (String resourceSet)
{
_rsrcSet = resourceSet;
}
/**
* Fetches the icon with the specified index from the named icon set.
*/
public Icon getIcon (String iconSet, int index)
{
try {
// see if the tileset is already loaded
TileSet set = (TileSet)_icons.get(iconSet);
// load it up if not
if (set == null) {
String path = _config.getProperty(iconSet + PATH_SUFFIX);
if (StringUtil.blank(path)) {
throw new Exception("No path specified for icon set");
}
String metstr = _config.getProperty(iconSet + METRICS_SUFFIX);
if (StringUtil.blank(metstr)) {
throw new Exception("No metrics specified for icon set");
}
int[] metrics = StringUtil.parseIntArray(metstr);
if (metrics == null || metrics.length != 2) {
throw new Exception("Invalid icon set metrics " +
"[metrics=" + metstr + "]");
}
// load up the tileset
if (_rsrcSet == null) {
set = _tilemgr.loadTileSet(
path, metrics[0], metrics[1]);
} else {
set = _tilemgr.loadTileSet(
_rsrcSet, path, metrics[0], metrics[1]);
}
// cache it
_icons.put(iconSet, set);
}
// fetch the appropriate image and create an image icon
return new TileIcon(set.getTile(index));
} catch (Exception e) {
Log.warning("Unable to load icon [iconSet=" + iconSet +
", index=" + index + ", error=" + e + "].");
}
return _errorIcon;
}
/** The tile manager we use to load tilesets. */
protected TileManager _tilemgr;
/** Our configuration information. */
protected Properties _config;
/** The resource bundle from which we load icon images, or null if
* they should be loaded from the classpath. */
protected String _rsrcSet;
/** A cache of our icon tilesets. */
protected LRUHashMap _icons = new LRUHashMap(ICON_CACHE_SIZE);
/** The icon we return when we are unable to load a requested icon. */
protected Icon _errorIcon = new Icon() {
public void paintIcon (Component c, Graphics g, int x, int y) {
g.setColor(Color.black);
g.fillRect(x, y, 16, 16);
}
public int getIconWidth () {
return 16;
}
public int getIconHeight () {
return 16;
}
};
/** The suffix we append to an icon set name to obtain the tileset
* image path configuration parameter. */
protected static final String PATH_SUFFIX = ".path";
/** The suffix we append to an icon set name to obtain the tileset
* metrics configuration parameter. */
protected static final String METRICS_SUFFIX = ".metrics";
/** The maximum number of icon tilesets that may be cached at once. */
protected static final int ICON_CACHE_SIZE = 10;
}