net.sf.ehcache.store.MemoryStoreEvictionPolicy Maven / Gradle / Ivy
/**
* Copyright 2003-2009 Terracotta, Inc.
*
* 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 net.sf.ehcache.store;
import java.io.Serializable;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A typesafe enumeration of eviction policies.
* The policy used to evict elements from the {@link net.sf.ehcache.store.MemoryStore}.
* This can be one of:
*
* - LRU - least recently used
*
- LFU - least frequently used
*
- FIFO - first in first out, the oldest element by creation time
*
* The default value is LRU
*
* @author Greg Luck
* @version $Id: MemoryStoreEvictionPolicy.java 1406 2009-11-06 11:43:02Z gluck $
* @since 1.2
*/
public final class MemoryStoreEvictionPolicy implements Serializable {
/**
* LRU - least recently used.
*/
public static final MemoryStoreEvictionPolicy LRU = new MemoryStoreEvictionPolicy("LRU");
/**
* LFU - least frequently used.
*/
public static final MemoryStoreEvictionPolicy LFU = new MemoryStoreEvictionPolicy("LFU");
/**
* FIFO - first in first out, the oldest element by creation time.
*/
public static final MemoryStoreEvictionPolicy FIFO = new MemoryStoreEvictionPolicy("FIFO");
private static final Logger LOG = LoggerFactory.getLogger(MemoryStoreEvictionPolicy.class.getName());
private final String myName;
/**
* This class should not be subclassed or have instances created.
* @param policy
*/
private MemoryStoreEvictionPolicy(String policy) {
myName = policy;
}
/**
* @return a String representation of the policy
*/
public String toString() {
return myName;
}
/**
* Converts a string representation of the policy into a policy.
*
* @param policy either LRU, LFU or FIFO
* @return one of the static instances
*/
public static MemoryStoreEvictionPolicy fromString(String policy) {
if (policy != null) {
if (policy.equalsIgnoreCase("LRU")) {
return LRU;
} else if (policy.equalsIgnoreCase("LFU")) {
return LFU;
} else if (policy.equalsIgnoreCase("FIFO")) {
return FIFO;
}
}
LOG.warn("The memoryStoreEvictionPolicy of {} cannot be resolved. The policy will be set to LRU", policy);
return LRU;
}
}