/*
* Copyright 2012-2015 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 java.util.Collection;
import org.springframework.boot.actuate.metrics.Metric;
/**
* Snapshot of the statistics of a given cache. {@code CacheStatistics} instances have a
* very short life as it represents the statistics of a cache at one particular point in
* time.
*
* @author Stephane Nicoll
* @since 1.3.0
*/
public interface CacheStatistics {
/**
* Generate the relevant {@link Metric} instances based on the specified prefix.
* @param prefix the metrics prefix (ends with '.')
* @return the metrics corresponding to this instance
*/
Collection<Metric<?>> toMetrics(String prefix);
/**
* Return the size of the cache or {@code null} if that information is not available.
* @return the size of the cache or {@code null}
*/
Long getSize();
/**
* Return the ratio of cache requests which were hits as a value between 0 and 1 where
* 0 means that the hit ratio is 0% and 1 means it is 100%.
* <p>
* This may also return {@code null} if the cache-specifics statistics does not
* provide the necessary information
* @return the hit ratio or {@code null}
*/
Double getHitRatio();
/**
* Return the ratio of cache requests which were misses as value between 0 and 1 where
* 0 means that the miss ratio is 0% and 1 means it is 100%.
* <p>
* This may also return {@code null} if the cache-specifics statistics does not
* provide the necessary information
* @return the miss ratio or {@code null}
*/
Double getMissRatio();
}