org.apache.axis2.classloader.BeanInfoCache Maven / Gradle / Ivy
/*
* 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
* under the License.
*/
package org.apache.axis2.classloader;
import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* {@link BeanInfo} cache that stores introspection results by bean class and stop class. This goes
* beyond the caching provided by the JRE, which only caches the results of
* {@link Introspector#getBeanInfo(Class)}, but not the results of
* {@link Introspector#getBeanInfo(Class, Class)} (with non null stop class).
*
* To avoid class loader leaks, this class should not be used as a singleton if the introspected
* classes are loaded from class loaders that are children of the class loader which holds the
* reference to the cache. In such scenarios, use {@link #getCachedBeanInfo(Class, Class)}.
*/
public final class BeanInfoCache {
private static final class CacheKey {
private final Class beanClass;
private final Class stopClass;
CacheKey(Class beanClass, Class stopClass) {
this.beanClass = beanClass;
this.stopClass = stopClass;
}
@Override
public int hashCode() {
return 31*beanClass.hashCode() + (stopClass == null ? 0 : stopClass.hashCode());
}
@Override
public boolean equals(Object obj) {
if (obj instanceof CacheKey) {
CacheKey other = (CacheKey)obj;
return beanClass == other.beanClass && stopClass == other.stopClass;
} else {
return false;
}
}
}
private static final Log log = LogFactory.getLog(BeanInfoCache.class);
/**
* Local cache instance for Javabeans that are loaded from the same class loader as this class.
*/
private static final BeanInfoCache localCache = new BeanInfoCache();
private final Map cache = new ConcurrentHashMap();
/**
* Introspect on a Java bean and return a cached {@link BeanInfo} object.
*
* @param beanClass
* The bean class to be analyzed.
* @param stopClass
* The base class at which to stop the analysis; may be null.
* @return A {@link BeanInfo} object describing the target bean.
* @exception IntrospectionException
* if an exception occurs during introspection.
* @see Introspector#getBeanInfo(Class, Class)
*/
public BeanInfo getBeanInfo(Class beanClass, Class stopClass) throws IntrospectionException {
CacheKey key = new CacheKey(beanClass, stopClass);
BeanInfo beanInfo = cache.get(key);
if (beanInfo == null) {
beanInfo = Introspector.getBeanInfo(beanClass, stopClass);
cache.put(key, beanInfo);
}
return beanInfo;
}
/**
* Locate an appropriate {@link BeanInfoCache} and return a cached {@link BeanInfo} object.
* This method ensures that caching the {@link BeanInfo} object will not result in a class
* loader leak.
*
* @param beanClass
* The bean class to be analyzed.
* @param stopClass
* The base class at which to stop the analysis; may be null.
* @return A {@link BeanInfo} object describing the target bean.
* @exception IntrospectionException
* if an exception occurs during introspection.
*/
public static BeanInfo getCachedBeanInfo(Class beanClass, Class stopClass) throws IntrospectionException {
ClassLoader classLoader = beanClass.getClassLoader();
BeanInfoCache cache;
if (classLoader instanceof BeanInfoCachingClassLoader) {
cache = ((BeanInfoCachingClassLoader)classLoader).getBeanInfoCache();
} else if (classLoader == BeanInfoCache.class.getClassLoader()) {
cache = localCache;
} else {
cache = null;
}
if (cache != null) {
return cache.getBeanInfo(beanClass, stopClass);
} else {
if (log.isWarnEnabled()) {
log.warn("Unable to locate a BeanInfo cache for " + beanClass + " (stopClass=" + stopClass
+ "). This will negatively affect performance!");
}
return Introspector.getBeanInfo(beanClass, stopClass);
}
}
}