/*
* Copyright 2012-2016 the original author or authors.
*
* 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 org.springframework.boot.actuate.cache;
import net.sf.ehcache.statistics.StatisticsGateway;
import org.springframework.cache.CacheManager;
import org.springframework.cache.ehcache.EhCacheCache;
/**
* {@link CacheStatisticsProvider} implementation for EhCache.
*
* @author Stephane Nicoll
* @since 1.3.0
*/
public class EhCacheStatisticsProvider implements CacheStatisticsProvider<EhCacheCache> {
@Override
public CacheStatistics getCacheStatistics(CacheManager cacheManager,
EhCacheCache cache) {
DefaultCacheStatistics statistics = new DefaultCacheStatistics();
StatisticsGateway ehCacheStatistics = cache.getNativeCache().getStatistics();
statistics.setSize(ehCacheStatistics.getSize());
double hitRatio = cacheHitRatio(ehCacheStatistics);
if (!Double.isNaN(hitRatio)) {
// ratio is calculated 'racily' and can drift marginally above unity,
// so we cap it here
double sanitizedHitRatio = (hitRatio > 1 ? 1 : hitRatio);
statistics.setHitRatio(sanitizedHitRatio);
statistics.setMissRatio(1 - sanitizedHitRatio);
}
return statistics;
}
private double cacheHitRatio(StatisticsGateway stats) {
long hitCount = stats.cacheHitCount();
long missCount = stats.cacheMissCount();
return ((double) hitCount) / (hitCount + missCount);
}
}