/*
* Copyright 2002-2007 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.aop.framework;
import java.io.Serializable;
import org.springframework.aop.SpringProxy;
import org.springframework.util.ClassUtils;
/**
* Default {@link AopProxyFactory} implementation,
* creating either a CGLIB proxy or a JDK dynamic proxy.
*
* <p>Creates a CGLIB proxy if one the following is true
* for a given {@link AdvisedSupport} instance:
* <ul>
* <li>the "optimize" flag is set
* <li>the "proxyTargetClass" flag is set
* <li>no proxy interfaces have been specified
* </ul>
*
* <p>Note that the CGLIB library classes have to be present on
* the class path if an actual CGLIB proxy needs to be created.
*
* <p>In general, specify "proxyTargetClass" to enforce a CGLIB proxy,
* or specify one or more interfaces to use a JDK dynamic proxy.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @since 12.03.2004
* @see AdvisedSupport#setOptimize
* @see AdvisedSupport#setProxyTargetClass
* @see AdvisedSupport#setInterfaces
*/
public class DefaultAopProxyFactory implements AopProxyFactory, Serializable {
/** Whether the CGLIB2 library is present on the classpath */
private static final boolean cglibAvailable =
ClassUtils.isPresent("net.sf.cglib.proxy.Enhancer", DefaultAopProxyFactory.class.getClassLoader());
public AopProxy createAopProxy(AdvisedSupport config) throws AopConfigException {
if (config.isOptimize() || config.isProxyTargetClass() || hasNoUserSuppliedProxyInterfaces(config)) {
Class targetClass = config.getTargetClass();
if (targetClass == null) {
throw new AopConfigException("TargetSource cannot determine target class: " +
"Either an interface or a target is required for proxy creation.");
}
if (targetClass.isInterface()) {
return new JdkDynamicAopProxy(config);
}
if (!cglibAvailable) {
throw new AopConfigException(
"Cannot proxy target class because CGLIB2 is not available. " +
"Add CGLIB to the class path or specify proxy interfaces.");
}
return CglibProxyFactory.createCglibProxy(config);
}
else {
return new JdkDynamicAopProxy(config);
}
}
/**
* Determine whether the supplied {@link AdvisedSupport} has only the
* {@link org.springframework.aop.SpringProxy} interface specified
* (or no proxy interfaces specified at all).
*/
private boolean hasNoUserSuppliedProxyInterfaces(AdvisedSupport config) {
Class[] interfaces = config.getProxiedInterfaces();
return (interfaces.length == 0 || (interfaces.length == 1 && SpringProxy.class.equals(interfaces[0])));
}
/**
* Inner factory class used to just introduce a CGLIB2 dependency
* when actually creating a CGLIB proxy.
*/
private static class CglibProxyFactory {
public static AopProxy createCglibProxy(AdvisedSupport advisedSupport) {
return new Cglib2AopProxy(advisedSupport);
}
}
}