/**
* Copyright 2005-2014 Restlet
*
* The contents of this file are subject to the terms of one of the following
* open source licenses: Apache 2.0 or or EPL 1.0 (the "Licenses"). You can
* select the license that you prefer but you may not use this file except in
* compliance with one of these Licenses.
*
* You can obtain a copy of the Apache 2.0 license at
* http://www.opensource.org/licenses/apache-2.0
*
* You can obtain a copy of the EPL 1.0 license at
* http://www.opensource.org/licenses/eclipse-1.0
*
* See the Licenses for the specific language governing permissions and
* limitations under the Licenses.
*
* Alternatively, you can obtain a royalty free commercial license with less
* limitations, transferable or non-transferable, directly at
* http://restlet.com/products/restlet-framework
*
* Restlet is a registered trademark of Restlet S.A.S.
*/
package org.restlet.ext.apispark.internal.firewall.rule;
import java.util.concurrent.TimeUnit;
import org.restlet.ext.apispark.internal.firewall.rule.counter.PeriodicCounter;
import org.restlet.ext.apispark.internal.firewall.rule.policy.CountingPolicy;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
/**
* {@link FirewallCounterRule} specialized in counting requests on a specific
* period of time. For each countedValue (value returned by the
* {@link CountingPolicy}), a {@link PeriodicCounter} is associated.
*
* @author Guillaume Blondeau
*/
public class PeriodicFirewallCounterRule extends FirewallCounterRule {
/** Cache of {@link PeriodicCounter}. */
private LoadingCache<String, PeriodicCounter> cache;
/** Period in second associated to the {@link FirewallCounterRule} */
private long period;
/**
* Contructor.
*
* @param period
* Period associated to the {@link PeriodicFirewallCounterRule}.
* Each created {@link PeriodicCounter} will have this one.
* @param periodUnit
* Period time unit associated to the {@link FirewallCounterRule}
* .
* @param countingPolicy
* The associated counting policy.
*/
public PeriodicFirewallCounterRule(int period, TimeUnit periodUnit,
CountingPolicy countingPolicy) {
super(countingPolicy);
this.period = periodUnit.toSeconds(period);
initializeCache();
}
/**
* Does nothing.
*/
@Override
protected void decrementCounter(String countedValue) {
}
@Override
protected CounterResult incrementCounter(String countedValue) {
PeriodicCounter individualCounter = cache.getUnchecked(countedValue);
return individualCounter.increment();
}
private void initializeCache() {
CacheLoader<String, PeriodicCounter> loader = new CacheLoader<String, PeriodicCounter>() {
public PeriodicCounter load(String key) {
return new PeriodicCounter(period);
}
};
// do not set cache expiration below 1 minute
long cacheExpiration = 2 * period < TimeUnit.MINUTES.toSeconds(1) ? TimeUnit.MINUTES
.toSeconds(1) : 2 * period;
cache = CacheBuilder.newBuilder()
.expireAfterAccess(cacheExpiration, TimeUnit.SECONDS)
.build(loader);
}
}