defaultaopproxyfactory.java

一个关于Spring框架的示例应用程序,简单使用,可以参考.

/*
 * Copyright 2002-2004 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 org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Simple implementation of AopProxyFactory,
 * either creating a CGLIB proxy or a JDK dynamic proxy.
 *
 * <p>Creates a CGLIB proxy if one the following is true:
 * <ul>
 * <li>the "optimize" flag is set
 * <li>the "proxyTargetClass" flag is set
 * <li>no interfaces have been specified
 * </ul>
 *
 * <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 Cglib2AopProxy
 * @see JdkDynamicAopProxy
 * @see AdvisedSupport#setOptimize
 * @see AdvisedSupport#setProxyTargetClass
 * @see AdvisedSupport#setInterfaces
 */
public class DefaultAopProxyFactory implements AopProxyFactory {

	private static final String CGLIB_ENHANCER_CLASS_NAME = "net.sf.cglib.proxy.Enhancer";

	private static final Log logger = LogFactory.getLog(DefaultAopProxyFactory.class);

	private static boolean cglibAvailable;

	static {
		// Determine whether CGLIB2 is available.
		// If not, we can't create proxies for full target class.
		try {
			Class.forName(CGLIB_ENHANCER_CLASS_NAME);
			cglibAvailable = true;
			logger.info("CGLIB2 available: proxyTargetClass feature enabled");
		}
		catch (ClassNotFoundException ex) {
			cglibAvailable = false;
			logger.info("CGLIB2 not available: proxyTargetClass feature disabled");
		}
	}


	public AopProxy createAopProxy(AdvisedSupport advisedSupport) throws AopConfigException {
		if (advisedSupport.isOptimize() || advisedSupport.isProxyTargetClass() ||
		    advisedSupport.getProxiedInterfaces().length == 0) {
			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(advisedSupport);
		}
		else {
			return new JdkDynamicAopProxy(advisedSupport);
		}
	}


	/**
	 * Inner class to just introduce a CGLIB2 dependency
	 * when actually creating a CGLIB proxy.
	 */
	private static class CglibProxyFactory {

		private static AopProxy createCglibProxy(AdvisedSupport advisedSupport) {
			return new Cglib2AopProxy(advisedSupport);
		}
	}

}