org.springframework.cache.support.AbstractCacheManager Maven / Gradle / Ivy
Show all versions of spring-context Show documentation
/*
* Copyright 2002-2014 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.cache.support;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.cache.Cache;
import org.springframework.cache.CacheManager;
/**
* Abstract base class implementing the common {@link CacheManager} methods.
* Useful for 'static' environments where the backing caches do not change.
*
* @author Costin Leau
* @author Juergen Hoeller
* @author Stephane Nicoll
* @since 3.1
*/
public abstract class AbstractCacheManager implements CacheManager, InitializingBean {
private final ConcurrentMap cacheMap = new ConcurrentHashMap(16);
private Set cacheNames = new LinkedHashSet(16);
// Early cache initialization on startup
@Override
public void afterPropertiesSet() {
Collection caches = loadCaches();
// Preserve the initial order of the cache names
this.cacheMap.clear();
this.cacheNames.clear();
for (Cache cache : caches) {
addCache(cache);
}
}
/**
* Load the initial caches for this cache manager.
* Called by {@link #afterPropertiesSet()} on startup.
* The returned collection may be empty but must not be {@code null}.
*/
protected abstract Collection loadCaches();
// Lazy cache initialization on access
@Override
public Cache getCache(String name) {
Cache cache = lookupCache(name);
if (cache != null) {
return cache;
}
else {
Cache missingCache = getMissingCache(name);
if (missingCache != null) {
addCache(missingCache);
return lookupCache(name); // may be decorated
}
return null;
}
}
@Override
public Collection getCacheNames() {
return Collections.unmodifiableSet(this.cacheNames);
}
// Common cache initialization delegates/callbacks
protected final void addCache(Cache cache) {
this.cacheMap.put(cache.getName(), decorateCache(cache));
this.cacheNames.add(cache.getName());
}
protected final Cache lookupCache(String name) {
return this.cacheMap.get(name);
}
/**
* Decorate the given Cache object if necessary.
* @param cache the Cache object to be added to this CacheManager
* @return the decorated Cache object to be used instead,
* or simply the passed-in Cache object by default
*/
protected Cache decorateCache(Cache cache) {
return cache;
}
/**
* Return a missing cache with the specified {@code name} or {@code null} if
* such cache does not exist or could not be created on the fly.
* Some caches may be created at runtime in the native provided. If a lookup
* by name does not yield any result, a subclass gets a chance to register
* such a cache at runtime. The returned cache will be automatically added to
* this instance.
* @param name the name of the cache to retrieve
* @return the missing cache or {@code null} if no such cache exists or could be
* created
* @see #getCache(String)
*/
protected Cache getMissingCache(String name) {
return null;
}
}