/*
* Copyright 2002-2011 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.annotation;
import java.util.Collection;
import java.util.Map;
import javax.annotation.PostConstruct;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.CacheManager;
import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportAware;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.util.Assert;
import org.springframework.util.CollectionUtils;
/**
* Abstract base {@code @Configuration} class providing common structure for enabling
* Spring's annotation-driven cache management capability.
*
* @author Chris Beams
* @since 3.1
* @see EnableCaching
*/
@Configuration
public abstract class AbstractCachingConfiguration implements ImportAware {
/** Parsed annotation metadata for {@code @EnableCaching} on the importing class. */
protected Map<String, Object> enableCaching;
protected CacheManager cacheManager;
protected KeyGenerator keyGenerator;
@Autowired(required=false)
private Collection<CacheManager> cacheManagerBeans;
@Autowired(required=false)
private Collection<CachingConfigurer> cachingConfigurers;
public void setImportMetadata(AnnotationMetadata importMetadata) {
this.enableCaching = importMetadata.getAnnotationAttributes(
EnableCaching.class.getName(), false);
Assert.notNull(this.enableCaching,
"@EnableCaching is not present on importing class " +
importMetadata.getClassName());
}
/**
* Determine which {@code CacheManager} bean to use. Prefer the result of
* {@link CachingConfigurer#cacheManager()} over any by-type matching. If none, fall
* back to by-type matching on {@code CacheManager}.
* @throws IllegalArgumentException if no CacheManager can be found; if more than one
* CachingConfigurer implementation exists; if multiple CacheManager beans and no
* CachingConfigurer exists to disambiguate.
*/
@PostConstruct
protected void reconcileCacheManager() {
if (!CollectionUtils.isEmpty(cachingConfigurers)) {
int nConfigurers = cachingConfigurers.size();
if (nConfigurers > 1) {
throw new IllegalStateException(nConfigurers + " implementations of " +
"CachingConfigurer were found when only 1 was expected. " +
"Refactor the configuration such that CachingConfigurer is " +
"implemented only once or not at all.");
}
CachingConfigurer cachingConfigurer = cachingConfigurers.iterator().next();
this.cacheManager = cachingConfigurer.cacheManager();
this.keyGenerator = cachingConfigurer.keyGenerator();
}
else if (!CollectionUtils.isEmpty(cacheManagerBeans)) {
int nManagers = cacheManagerBeans.size();
if (nManagers > 1) {
throw new IllegalStateException(nManagers + " beans of type CacheManager " +
"were found when only 1 was expected. Remove all but one of the " +
"CacheManager bean definitions, or implement CachingConfigurer " +
"to make explicit which CacheManager should be used for " +
"annotation-driven cache management.");
}
CacheManager cacheManager = cacheManagerBeans.iterator().next();
this.cacheManager = cacheManager;
// keyGenerator remains null; will fall back to default within CacheInterceptor
}
else {
throw new IllegalStateException("No bean of type CacheManager could be found. " +
"Register a CacheManager bean or remove the @EnableCaching annotation " +
"from your configuration.");
}
}
}