org.springframework.core.type.classreading.CachingMetadataReaderFactory Maven / Gradle / Ivy
/*
* Copyright 2002-2016 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
*
* https://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.core.type.classreading;
import java.io.IOException;
import java.util.LinkedHashMap;
import java.util.Map;
import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceLoader;
/**
* Caching implementation of the {@link MetadataReaderFactory} interface,
* caching a {@link MetadataReader} instance per Spring {@link Resource} handle
* (i.e. per ".class" file).
*
* @author Juergen Hoeller
* @author Costin Leau
* @since 2.5
*/
public class CachingMetadataReaderFactory extends SimpleMetadataReaderFactory {
/** Default maximum number of entries for the MetadataReader cache: 256 */
public static final int DEFAULT_CACHE_LIMIT = 256;
private volatile int cacheLimit = DEFAULT_CACHE_LIMIT;
@SuppressWarnings("serial")
private final Map metadataReaderCache =
new LinkedHashMap(DEFAULT_CACHE_LIMIT, 0.75f, true) {
@Override
protected boolean removeEldestEntry(Map.Entry eldest) {
return size() > getCacheLimit();
}
};
/**
* Create a new CachingMetadataReaderFactory for the default class loader.
*/
public CachingMetadataReaderFactory() {
super();
}
/**
* Create a new CachingMetadataReaderFactory for the given resource loader.
* @param resourceLoader the Spring ResourceLoader to use
* (also determines the ClassLoader to use)
*/
public CachingMetadataReaderFactory(ResourceLoader resourceLoader) {
super(resourceLoader);
}
/**
* Create a new CachingMetadataReaderFactory for the given class loader.
* @param classLoader the ClassLoader to use
*/
public CachingMetadataReaderFactory(ClassLoader classLoader) {
super(classLoader);
}
/**
* Specify the maximum number of entries for the MetadataReader cache.
* Default is 256.
*/
public void setCacheLimit(int cacheLimit) {
this.cacheLimit = cacheLimit;
}
/**
* Return the maximum number of entries for the MetadataReader cache.
*/
public int getCacheLimit() {
return this.cacheLimit;
}
@Override
public MetadataReader getMetadataReader(Resource resource) throws IOException {
if (getCacheLimit() <= 0) {
return super.getMetadataReader(resource);
}
synchronized (this.metadataReaderCache) {
MetadataReader metadataReader = this.metadataReaderCache.get(resource);
if (metadataReader == null) {
metadataReader = super.getMetadataReader(resource);
this.metadataReaderCache.put(resource, metadataReader);
}
return metadataReader;
}
}
/**
* Clear the entire MetadataReader cache, removing all cached class metadata.
*/
public void clearCache() {
synchronized (this.metadataReaderCache) {
this.metadataReaderCache.clear();
}
}
}