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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
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package org.apache.cayenne.cache;
import java.io.Serializable;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.query.QueryMetadata;
import org.apache.commons.collections.map.LRUMap;
/**
* A default implementation of the {@link QueryCache} interface that stores data in a
* non-expiring LRUMap.
*
* @since 3.0
*/
public class MapQueryCache implements QueryCache, Serializable {
public static final int DEFAULT_CACHE_SIZE = 1000;
static final String DEFAULT_CACHE_NAME = "cayenne.default.cache";
protected final Map<String, Map<String, List<?>>> cacheGroups;
private int maxSize;
public MapQueryCache() {
this(DEFAULT_CACHE_SIZE);
}
public MapQueryCache(int maxSize) {
this.cacheGroups = new ConcurrentHashMap<>();
this.maxSize = maxSize;
}
public List get(QueryMetadata metadata) {
String key = metadata.getCacheKey();
if (key == null) {
return null;
}
Map<String, List<?>> map = createIfAbsent(metadata);
synchronized (map) {
return map.get(key);
}
}
/**
* Returns a non-null cached value. If it is not present in the cache, it is obtained
* by calling {@link QueryCacheEntryFactory#createObject()} without blocking the cache. As
* a result there is a potential of multiple threads to be updating cache in parallel -
* this wouldn't lead to corruption of the cache, but can be suboptimal.
*/
@SuppressWarnings("rawtypes")
public List get(QueryMetadata metadata, QueryCacheEntryFactory factory) {
List result = get(metadata);
if (result == null) {
List newObject = factory.createObject();
if (newObject == null) {
throw new CayenneRuntimeException("Null on cache rebuilding: %s", metadata.getCacheKey());
}
result = newObject;
put(metadata, result);
}
return result;
}
public void put(QueryMetadata metadata, List results) {
String key = metadata.getCacheKey();
if (key == null) {
return;
}
Map<String, List<?>> map = createIfAbsent(metadata);
synchronized (map) {
map.put(key, results);
}
}
public void remove(String key) {
if (key == null) {
return;
}
for(Map<String, List<?>> map : cacheGroups.values()) {
synchronized (map) {
map.remove(key);
}
}
}
public void removeGroup(String groupKey) {
if (groupKey != null) {
cacheGroups.remove(groupKey);
}
}
public void removeGroup(String groupKey, Class<?> keyType, Class<?> valueType) {
removeGroup(groupKey);
}
public void clear() {
cacheGroups.clear();
}
public int size() {
int size = 0;
for(Map<String, List<?>> map : cacheGroups.values()) {
synchronized (map) {
size += map.size();
}
}
return size;
}
protected Map<String, List<?>> createIfAbsent(QueryMetadata metadata) {
return createIfAbsent(cacheName(metadata));
}
protected Map<String, List<?>> createIfAbsent(String cacheName) {
Map<String, List<?>> cache = getCache(cacheName);
if (cache == null) {
cache = createCache(cacheName);
}
return cache;
}
@SuppressWarnings("unchecked")
protected synchronized Map<String, List<?>> createCache(String cacheName) {
Map<String, List<?>> map = getCache(cacheName);
if(map != null) {
return map;
}
map = new LRUMap(maxSize);
cacheGroups.put(cacheName, map);
return map;
}
protected Map<String, List<?>> getCache(String name) {
return cacheGroups.get(name);
}
protected String cacheName(QueryMetadata metadata) {
String cacheGroup = metadata.getCacheGroup();
if (cacheGroup != null) {
return cacheGroup;
}
// no explicit cache group
return DEFAULT_CACHE_NAME;
}
}