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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.dubbo.cache.support.lfu;
import org.apache.dubbo.cache.Cache;
import org.apache.dubbo.common.URL;
import org.apache.dubbo.common.utils.LFUCache;
/**
* This class store the cache value per thread. If a service,method,consumer or provided is configured with key cache
* with value lfu, dubbo initialize the instance of this class using {@link LfuCacheFactory} to store method's returns value
* to server from store without making method call.
*
* e.g. 1) <dubbo:service cache="lfu" cache.size="5000" cache.evictionFactor="0.3"/>
* 2) <dubbo:consumer cache="lfu" />
*
*
* LfuCache uses url's cache.size value for its max store size, url's cache.evictionFactor value for its eviction factor,
* default store size value will be 1000, default eviction factor will be 0.3
*
*
* @see Cache
* @see LfuCacheFactory
* @see org.apache.dubbo.cache.support.AbstractCacheFactory
* @see org.apache.dubbo.cache.filter.CacheFilter
*/
public class LfuCache implements Cache {
/**
* This is used to store cache records
*/
private final LFUCache store;
/**
* Initialize LfuCache, it uses constructor argument cache.size value as its storage max size.
* If nothing is provided then it will use 1000 as default size value. cache.evictionFactor value as its eviction factor.
* If nothing is provided then it will use 0.3 as default value.
* @param url A valid URL instance
*/
public LfuCache (URL url) {
final int max = url.getParameter("cache.size", 1000);
final float factor = url.getParameter("cache.evictionFactor", 0.75f);
this.store = new LFUCache(max, factor);
}
/**
* API to store value against a key in the calling thread scope.
* @param key Unique identifier for the object being store.
* @param value Value getting store
*/
@Override
public void put(Object key, Object value) {
store.put(key, value);
}
/**
* API to return stored value using a key against the calling thread specific store.
* @param key Unique identifier for cache lookup
* @return Return stored object against key
*/
@Override
public Object get(Object key) {
return store.get(key);
}
}