/*
* Copyright 2009 James Abley
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.eternus.ratelimit;
import net.sf.ehcache.Ehcache;
import net.sf.ehcache.Element;
import net.sf.ehcache.constructs.blocking.BlockingCache;
import net.sf.ehcache.constructs.blocking.LockTimeoutException;
/**
* {@link TokenStore} implementation that uses ehcache as the backing store for {@link StoreEntry}s.
*
* @author jabley
*
*/
public class EhcacheTokenStore implements TokenStore {
/**
* The {@link BlockingCache} used to back this {@link TokenStore}.
*/
private BlockingCache cache;
/**
* Sets the non-null {@link Ehcache} used to back this {@link TokenStore}.
*
* @param cache
* a non-null {@link Ehcache}
*/
public void setCache(Ehcache cache) {
BlockingCache ref;
if (!(cache instanceof BlockingCache)) {
ref = new BlockingCache(cache);
cache.getCacheManager().replaceCacheWithDecoratedCache(cache, new BlockingCache(cache));
} else {
ref = (BlockingCache) cache;
}
this.cache = ref;
}
/**
* {@inheritDoc}
*/
public StoreEntry create(Key key, int timeToLive) {
StoreEntryImpl result = new StoreEntryImpl(timeToLive);
Element element = new Element(key, result);
element.setTimeToLive(timeToLive);
cache.put(element);
return result;
}
/**
* {@inheritDoc}
*/
public StoreEntry get(Key key) {
Element entry = null;
try {
/* This may block. */
entry = cache.get(key);
} catch (LockTimeoutException e) {
throw new RuntimeException();
} catch (RuntimeException e) {
/* Release the lock that may have been acquired. */
cache.put(new Element(key, null));
}
StoreEntry result = null;
if (entry != null) {
/*
* We don't need to check isExpired() on the result, since ehcache takes care of expiring entries for us.
* c.f. the get(Key) implementation in this class.
*/
result = (StoreEntry) entry.getObjectValue();
}
return result;
}
}