public Cache<String, Object> createCache(String name) {
// Get cache configuration from system properties or default (hardcoded) values
long maxSize = CacheFactory.getMaxCacheSize(name);
long lifetime = CacheFactory.getMaxCacheLifetime(name);
// Create cache with located properties
return new DefaultCache<String, Object>(name, maxSize, lifetime);
}
/**
* Ask the CacheManager to construct a cache.
*
* <p>Normally the CacheManager will use whatever CacheFactory has been chosen for the system via
* the cache.defaultFactory property. However, it is possible to override the use of the default
* factory by supplying a "factory" property to this method. The value should be the full
* classname for the factory you want to use for constructing the cache.
*
* <p>example: factory -> org.apache.roller.weblogger.util.cache.LRUCacheFactoryImpl
*
* <p>This allows Roller admins the ability to choose a caching strategy to use for the whole
* system, but override it in certain places where they see fit. It also allows users to write
* their own caching modifications and have them used only by specific caches.
*/
public static Cache constructCache(CacheHandler handler, Map properties) {
log.debug("Constructing new cache with props " + properties);
Cache cache = null;
if (properties != null && properties.containsKey("factory")) {
// someone wants a custom cache instance
String classname = (String) properties.get("factory");
try {
// use reflection to instantiate the factory class
Class factoryClass = Class.forName(classname);
log.info("PageCacheFactory:" + factoryClass);
CacheFactory factory = (CacheFactory) factoryClass.newInstance();
// now ask for a new cache
cache = factory.constructCache(properties);
} catch (ClassCastException cce) {
log.error(
"It appears that your factory ["
+ classname
+ "] does not implement the CacheFactory interface",
cce);
} catch (Exception e) {
log.error(
"Unable to instantiate cache factory [" + classname + "] falling back on default", e);
}
}
if (cache == null) {
// ask our default cache factory for a new cache instance
cache = cacheFactory.constructCache(properties);
}
if (cache != null) {
caches.put(cache.getId(), cache);
// register the handler for this new cache
if (handler != null) {
cacheHandlers.add(handler);
}
}
return cache;
}
static {
// lookup what cache factory we want to use
String classname = WebloggerConfig.getProperty("cache.defaultFactory");
// use reflection to instantiate our factory class
try {
Class factoryClass = Class.forName(classname);
cacheFactory = (CacheFactory) factoryClass.newInstance();
} catch (ClassCastException cce) {
log.error(
"It appears that your factory does not implement " + "the CacheFactory interface", cce);
} catch (Exception e) {
log.error(
"Unable to instantiate cache factory [" + classname + "]" + " falling back on default",
e);
}
if (cacheFactory == null)
try {
// hmm ... failed to load the specified cache factory
// lets try our default
Class factoryClass = Class.forName(DEFAULT_FACTORY);
cacheFactory = (CacheFactory) factoryClass.newInstance();
} catch (Exception e) {
log.fatal("Failed to instantiate a cache factory", e);
throw new RuntimeException(e);
}
log.info("Cache Manager Initialized.");
log.info("Cache Factory = " + cacheFactory.getClass().getName());
// add custom handlers
String customHandlers = WebloggerConfig.getProperty("cache.customHandlers");
if (customHandlers != null && customHandlers.trim().length() > 0) {
String[] cHandlers = customHandlers.split(",");
for (int i = 0; i < cHandlers.length; i++) {
// use reflection to instantiate the handler class
try {
Class handlerClass = Class.forName(cHandlers[i]);
CacheHandler customHandler = (CacheHandler) handlerClass.newInstance();
cacheHandlers.add(customHandler);
} catch (ClassCastException cce) {
log.error(
"It appears that your handler does not implement " + "the CacheHandler interface",
cce);
} catch (Exception e) {
log.error("Unable to instantiate cache handler [" + cHandlers[i] + "]", e);
}
}
}
}