The resource manager can load resources from the default resource * set, and can make available named resource sets to entities that wish * to do their own resource loading. If the resource manager fails to * locate a resource in the default resource set, it falls back to loading * the resource via the classloader (which will search the classpath). * *
Applications that wish to make use of resource sets and their * associated bundles must call {@link #initBundles} after constructing * the resource manager, providing the URL of a resource definition file * which describes these resource sets. The definition file will be loaded * and the resource bundles defined within will be loaded relative to the * resource definition URL. The bundles will be cached in the user's home * directory and only reloaded when the source resources have been * updated. The resource definition file looks something like the * following: * *
* resource.set.default = sets/misc/config.jar: \ * sets/misc/icons.jar * resource.set.tiles = sets/tiles/ground.jar: \ * sets/tiles/objects.jar: \ * /global/resources/tiles/ground.jar: \ * /global/resources/tiles/objects.jar * resource.set.sounds = sets/sounds/sfx.jar: \ * sets/sounds/music.jar: \ * /global/resources/sounds/sfx.jar: \ * /global/resources/sounds/music.jar ** *
All resource set definitions are prefixed with
* resource.set. and all text following that string is
* considered to be the name of the resource set. The resource set named
* default is the default resource set and is the one that is
* searched for resources is a call to {@link #getResource}.
*
*
When a resource is loaded from a resource set, the set is searched
* in the order that entries are specified in the definition.
*/
public class ResourceManager
{
/**
* Provides facilities for notifying an observer of resource bundle
* download progress.
*/
public interface BundleDownloadObserver
{
/**
* Called when the resource manager is about to check for an
* update of any of our resource sets.
*/
public void checkingForUpdate ();
/**
* Called to inform the observer of ongoing progress toward
* completion of the overall bundle downloading task. The caller
* is guaranteed to get at least one call reporting 100%
* completion.
*/
public void downloadProgress (int percent);
/**
* Called if a failure occurs while checking for an update or
* downloading all resource sets.
*/
public void downloadFailed (Exception e);
}
/**
* Constructs a resource manager which will load resources via the
* classloader, prepending resourceRoot to their path.
*
* @param resourceRoot the path to prepend to resource paths prior to
* attempting to load them via the classloader. When resources are
* bundled into the default resource bundle, they don't need this
* prefix, but if they're to be loaded from the classpath, it's likely
* that they'll live in some sort of resources directory
* to isolate them from the rest of the files in the classpath. This
* is not a platform dependent path (forward slash is always used to
* separate path elements).
*/
public ResourceManager (String resourceRoot)
{
// keep track of our root path
_rootPath = resourceRoot;
// make root path end with a slash (not the platform dependent
// file system separator character as resource paths are passed to
// ClassLoader.getResource() which requires / as its separator)
if (!_rootPath.endsWith("/")) {
_rootPath = _rootPath + "/";
}
// use the classloader that loaded us
_loader = getClass().getClassLoader();
}
/**
* Initializes the bundle sets to be made available by this resource
* manager. Applications that wish to make use of resource bundles
* should call this method after constructing the resource manager.
*
* @param resourceURL the base URL from which resources are loaded.
* Relative paths specified in the resource definition file will be
* loaded relative to this path. If this is null, the system property
* resource_url will be used, if available.
* @param configPath the path (relative to the resource URL) of the
* resource definition file.
* @param downloadObs the bundle download observer to notify of
* download progress and success or failure, or null if
* the caller doesn't care to be informed; note that in the latter
* case, the calling thread will block until bundle updating is
* complete.
*/
public void initBundles (String resourceURL, String configPath,
BundleDownloadObserver downloadObs)
{
// if the resource URL wasn't provided, we try to figure it out
// for ourselves
if (resourceURL == null) {
try {
// first look for the explicit system property
resourceURL = System.getProperty("resource_url");
// if that doesn't work, fall back to the current directory
if (resourceURL == null) {
resourceURL = "file:" + System.getProperty("user.dir");
}
} catch (SecurityException se) {
resourceURL = "file:" + File.separator;
}
}
// make sure there's a slash at the end of the URL
if (!resourceURL.endsWith("/")) {
resourceURL += "/";
}
URL rurl = null;
try {
rurl = new URL(resourceURL);
} catch (MalformedURLException mue) {
Log.warning("Invalid resource URL [url=" + resourceURL +
", error=" + mue + "].");
}
// load up our configuration
Properties config = loadConfig(rurl, configPath);
// resolve the configured resource sets
ArrayList dlist = new ArrayList();
Enumeration names = config.propertyNames();
while (names.hasMoreElements()) {
String key = (String)names.nextElement();
if (!key.startsWith(RESOURCE_SET_PREFIX)) {
continue;
}
String setName = key.substring(RESOURCE_SET_PREFIX.length());
resolveResourceSet(rurl, setName, config.getProperty(key), dlist);
}
// start the download, blocking if we've no observer
DownloadManager dlmgr = new DownloadManager();
if (downloadObs == null) {
downloadBlocking(dlmgr, dlist);
} else {
downloadNonBlocking(dlmgr, dlist, downloadObs);
}
}
/**
* Downloads the files in the supplied download list, blocking the
* calling thread until the download is complete or a failure has
* occurred.
*/
protected void downloadBlocking (DownloadManager dlmgr, List dlist)
{
// create an object to wait on while the download takes place
final Object lock = new Object();
// pass the descriptors on to the download manager
dlmgr.download(dlist, true, new DownloadObserver() {
public void resolvingDownloads () {
// nothing for now
}
public void downloadProgress (int percent) {
if (percent == 100) {
synchronized (lock) {
// wake things up as the download is finished
lock.notify();
}
}
}
public void downloadFailed (DownloadDescriptor desc, Exception e) {
Log.warning("Failed to download file " +
"[desc=" + desc + ", e=" + e + "].");
synchronized (lock) {
// wake things up since we're fragile and so a
// single failure means all is booched
lock.notify();
}
}
});
try {
synchronized (lock) {
// block until the download has completed
lock.wait();
}
} catch (InterruptedException ie) {
Log.warning("Thread interrupted while waiting for download " +
"to complete [ie=" + ie + "].");
}
}
/**
* Downloads the files in the supplied download list asynchronously,
* notifying the download observer of ongoing progress.
*/
protected void downloadNonBlocking (
DownloadManager dlmgr, List dlist, final BundleDownloadObserver obs)
{
// pass the descriptors on to the download manager
dlmgr.download(dlist, true, new DownloadObserver() {
public void resolvingDownloads () {
obs.checkingForUpdate();
}
public void downloadProgress (int percent) {
obs.downloadProgress(percent);
}
public void downloadFailed (DownloadDescriptor desc, Exception e) {
obs.downloadFailed(e);
}
});
}
/**
* Loads up the most recent version of the resource manager
* configuration.
*/
protected Properties loadConfig (URL resourceURL, String configPath)
{
Properties config = new Properties();
URL curl = null;
try {
if (configPath != null) {
curl = new URL(resourceURL, configPath);
config.load(curl.openStream());
}
} catch (MalformedURLException mue) {
Log.warning("Unable to construct config URL " +
"[resourceURL=" + resourceURL +
", configPath=" + configPath +
", error=" + mue + "].");
} catch (IOException ioe) {
// complain if some other error occurs
Log.warning("Error loading resource manager configuration " +
"[url=" + curl + ", error=" + ioe + "].");
}
return config;
}
/**
* Ensures that the cache directory for the specified resource set is
* created.
*
* @return true if the directory was successfully created (or was
* already there), false if we failed to create it.
*/
protected boolean createCacheDirectory (String setName)
{
// get the path to the top-level cache directory if we don't
// already have it
if (_cachePath == null) {
try {
// first check for an explicitly specified cache directory
String dir = System.getProperty("rsrc_cache_dir");
// if that's null, try putting it into their home directory
if (dir == null) {
dir = System.getProperty("user.home") +
File.separator + CACHE_PATH;
}
_cachePath = (dir + File.separator);
} catch (SecurityException se) {
Log.info("Can't obtain user.home system property. Probably " +
"won't be able to create our cache directory " +
"either. [error=" + se + "].");
_cachePath = "";
}
}
// make sure the main cache directory exists
if (!createDirectory(_cachePath)) {
return false;
}
// ensure that the set-specific cache directory exists
return createDirectory(_cachePath + setName);
}
/**
* Creates the specified directory if it doesn't already exist.
*
* @return true if directory was created (or existed), false if not.
*/
protected boolean createDirectory (String path)
{
File cdir = new File(path);
if (cdir.exists()) {
if (!cdir.isDirectory()) {
Log.warning("Cache dir exists but isn't a directory?! " +
"[path=" + path + "].");
return false;
}
} else {
if (!cdir.mkdir()) {
Log.warning("Unable to create cache dir. " +
"[path=" + path + "].");
return false;
}
}
return true;
}
/**
* Generates the name of the bundle cache file given the name of the
* resource set to which it belongs and the relative path URL.
*/
protected String genCachePath (String setName, String resourcePath)
{
return _cachePath + setName + File.separator +
StringUtil.replace(resourcePath, "/", "-");
}
/**
* Loads up a resource set based on the supplied definition
* information.
*/
protected void resolveResourceSet (
URL resourceURL, String setName, String definition, List dlist)
{
StringTokenizer tok = new StringTokenizer(definition, ":");
ArrayList set = new ArrayList();
while (tok.hasMoreTokens()) {
String path = tok.nextToken().trim();
URL burl = null;
try {
burl = new URL(resourceURL, path);
// make sure the cache directory exists for this set
createCacheDirectory(setName);
// compute the path to the cache file for this bundle
File cfile = new File(genCachePath(setName, path));
// slap this on the list for retrieval or update by the
// download manager
dlist.add(new DownloadDescriptor(burl, cfile));
// finally, add the file that will be cached to the set as
// a resource bundle
set.add(new ResourceBundle(cfile));
} catch (MalformedURLException mue) {
Log.warning("Unable to create URL for resource " +
"[set=" + setName + ", path=" + path +
", error=" + mue + "].");
}
}
// convert our array list into an array and stick it in the table
ResourceBundle[] setvec = new ResourceBundle[set.size()];
set.toArray(setvec);
_sets.put(setName, setvec);
// if this is our default resource bundle, keep a reference to it
if (DEFAULT_RESOURCE_SET.equals(setName)) {
_default = setvec;
}
}
/**
* Fetches a resource from the local repository.
*
* @param path the path to the resource
* (ie. "config/miso.properties"). This should not begin with a slash.
*
* @exception IOException thrown if a problem occurs locating or
* reading the resource.
*/
public InputStream getResource (String path)
throws IOException
{
InputStream in = null;
// first look for this resource in our default resource bundle
for (int i = 0; i < _default.length; i++) {
in = _default[i].getResource(path);
if (in != null) {
return in;
}
}
// if we didn't find anything, try the classloader
String rpath = _rootPath + path;
in = _loader.getResourceAsStream(rpath);
if (in != null) {
return in;
}
// if we still haven't found it, we throw an exception
String errmsg = "Unable to locate resource [path=" + path + "]";
throw new FileNotFoundException(errmsg);
}
/**
* Returns a reference to the resource set with the specified name, or
* null if no set exists with that name. Services that wish to load
* their own resources can allow the resource manager to load up a
* resource set for them, from which they can easily load their
* resources.
*/
public ResourceBundle[] getResourceSet (String name)
{
return (ResourceBundle[])_sets.get(name);
}
/** The classloader we use for classpath-based resource loading. */
protected ClassLoader _loader;
/** The prefix we prepend to resource paths before attempting to load
* them from the classpath. */
protected String _rootPath;
/** The path to our bundle cache directory. */
protected String _cachePath;
/** Our default resource set. */
protected ResourceBundle[] _default = new ResourceBundle[0];
/** A table of our resource sets. */
protected HashMap _sets = new HashMap();
/** The prefix of configuration entries that describe a resource
* set. */
protected static final String RESOURCE_SET_PREFIX = "resource.set.";
/** The name of the default resource set. */
protected static final String DEFAULT_RESOURCE_SET = "default";
/** The name of our resource bundle cache directory. */
protected static final String CACHE_PATH = ".naryarsrc";
}