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package org.cache2k.operation;
/*
* #%L
* cache2k API
* %%
* Copyright (C) 2000 - 2021 headissue GmbH, Munich
* %%
* 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.
* #L%
*/
import org.cache2k.Cache;
import org.cache2k.Cache2kBuilder;
import org.cache2k.config.CacheType;
import org.cache2k.annotation.Nullable;
import java.time.Instant;
/**
* Information of a cache for introspection at runtime, for
* generic monitoring and management proposes. Additional information
* is available via {@link CacheStatistics} if statistics are enabled.
*
* It is intentionally that there is no way to retrieve the original
* configuration after creation.
*
* @author Jens Wilke
*/
public interface CacheInfo {
/**
* Request an instance for the given cache.
*/
static CacheInfo of(Cache cache) { return cache.requestInterface(CacheInfo.class); }
String getName();
String getManagerName();
/**
* Type of the cache key.
*/
CacheType getKeyType();
/**
* Type of the cache value.
*/
CacheType getValueType();
/**
* The current number of entries within the cache, starting with 0. This value is an
* estimate, when iterating the entries the cache will always return less or an
* identical number of entries.
*
*
Expired entries may stay in the cache {@link Cache2kBuilder#keepDataAfterExpired(boolean)}.
* These entries will be counted, but will not be returned by the iterator or a {@code peek}
* operation
*/
long getSize();
/**
* The configured maximum number of entries in the cache.
*/
long getEntryCapacity();
/**
* Configured maximum weight or -1.
*
* @see Weigher
* @see Cache2kBuilder#maximumWeight(long)
*/
long getMaximumWeight();
/**
* Total weight of all entries in the cache.
*
* @see Weigher
* @see Cache2kBuilder#maximumWeight(long)
*/
long getTotalWeight();
/**
* Either {@link #getMaximumWeight()} or {@link #getEntryCapacity()} depending
* on whether a weigher is present or not.
*
* @see Weigher
*/
long getCapacityLimit();
/**
* Descriptor of cache implementation in use. Either a class name or multiple class names.
*/
String getImplementation();
/**
* A loader is configured. This can be used to determine, whether it makes sense to
* send the report/monitor the loader metrics.
*/
boolean isLoaderPresent();
/**
* A weigher is configured. This can be used to determine, whether it makes sense to
* send the report/monitor the weigher metrics.
*/
boolean isWeigherPresent();
/**
* This cache supports statistics.
*/
boolean isStatisticsEnabled();
/**
* Time when the cache was created.
*
*
We use the old type {@code Date} and not {@code Instant} here in order to make this interface
* usable for JMX directly, which does not support {@code Instant}.
*/
Instant getCreatedTime();
/**
* Time of the most recent {@link org.cache2k.Cache#clear} operation.
*/
@Nullable Instant getClearedTime();
}