JdkDynamicAopProxy.java

/*
 * Copyright 2018 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 com.sandy.ecp.framework.aop;

import java.io.Serializable;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.SpringProxy;
import org.springframework.aop.framework.Advised;
import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopConfigException;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;
import org.springframework.core.DecoratingProxy;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * Delegate interface for a configured AOP proxy, allowing for the creation
 * of actual proxy objects.
 * @author Sandy
 * @since 1.0.0 2012-04-02 12:11:02
 */
public class JdkDynamicAopProxy implements AopProxy, InvocationHandler, Serializable {

	private static final long serialVersionUID = 5379337516488249352L;
	
	/** We use a static Log to avoid serialization issues */
	private static final Log logger = LogFactory.getLog(JdkDynamicAopProxy.class);
	
	// 目标类（被代理类）
    private Object target;
    
    /** Config used to configure this proxy */
	private AdvisedSupport advised;
    
    /**
	 * Is the {@link #equals} method defined on the proxied interfaces?
	 */
	private boolean equalsDefined;
	
	/**
	 * Is the {@link #hashCode} method defined on the proxied interfaces?
	 */
	private boolean hashCodeDefined;
	
	/**
	 * Construct a new JdkDynamicAopProxy for the given AOP configuration.
	 * @param config the AOP configuration as AdvisedSupport object
	 * @throws AopConfigException if the config is invalid. We try to throw an informative
	 * exception in this case, rather than let a mysterious failure happen later.
	 */
	public JdkDynamicAopProxy(AdvisedSupport config) throws AopConfigException {
		Assert.notNull(config, "AdvisedSupport must not be null");
		if (config.getAdvisors().length == 0 && config.getTargetSource() == AdvisedSupport.EMPTY_TARGET_SOURCE) {
			throw new AopConfigException("No advisors and no TargetSource specified");
		}
		this.advised = config;
	}

	@Override
	public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
		System.out.println("执行前...");
		if (target == null) {
			if (this.advised != null) {
				this.target = advised.getTargetSource();
			}
		}
        Object result = method.invoke(target, args);
        System.out.println("执行后...");
        System.out.println(proxy);
		return result;
	}

	@Override
	public Object getProxy() {
		return getProxy(ClassUtils.getDefaultClassLoader());
	}

	@Override
	public Object getProxy(ClassLoader classLoader) {
		if (logger.isDebugEnabled()) {
			logger.debug("Creating JDK dynamic proxy: target source is " + this.advised.getTargetSource());
		}
		Class<?>[] proxiedInterfaces = completeProxiedInterfaces(this.advised, true);
		findDefinedEqualsAndHashCodeMethods(proxiedInterfaces);
		return Proxy.newProxyInstance(classLoader, proxiedInterfaces, this);
	}
	
	/**
	 * Determine the complete set of interfaces to proxy for the given AOP configuration.
	 * <p>This will always add the {@link Advised} interface unless the AdvisedSupport's
	 * {@link AdvisedSupport#setOpaque "opaque"} flag is on. Always adds the
	 * {@link org.springframework.aop.SpringProxy} marker interface.
	 * @param advised the proxy config
	 * @param decoratingProxy whether to expose the {@link DecoratingProxy} interface
	 * @return the complete set of interfaces to proxy
	 * @since 4.3
	 * @see SpringProxy
	 * @see Advised
	 * @see DecoratingProxy
	 */
	static Class<?>[] completeProxiedInterfaces(AdvisedSupport advised, boolean decoratingProxy) {
		Class<?>[] specifiedInterfaces = advised.getProxiedInterfaces();
		if (specifiedInterfaces.length == 0) {
			// No user-specified interfaces: check whether target class is an interface.
			Class<?> targetClass = advised.getTargetClass();
			if (targetClass != null) {
				if (targetClass.isInterface()) {
					advised.setInterfaces(targetClass);
				}
				else if (Proxy.isProxyClass(targetClass)) {
					advised.setInterfaces(targetClass.getInterfaces());
				}
				specifiedInterfaces = advised.getProxiedInterfaces();
			}
		}
		boolean addSpringProxy = !advised.isInterfaceProxied(SpringProxy.class);
		boolean addAdvised = !advised.isOpaque() && !advised.isInterfaceProxied(Advised.class);
		boolean addDecoratingProxy = (decoratingProxy && !advised.isInterfaceProxied(DecoratingProxy.class));
		int nonUserIfcCount = 0;
		if (addSpringProxy) {
			nonUserIfcCount++;
		}
		if (addAdvised) {
			nonUserIfcCount++;
		}
		if (addDecoratingProxy) {
			nonUserIfcCount++;
		}
		Class<?>[] proxiedInterfaces = new Class<?>[specifiedInterfaces.length + nonUserIfcCount];
		System.arraycopy(specifiedInterfaces, 0, proxiedInterfaces, 0, specifiedInterfaces.length);
		int index = specifiedInterfaces.length;
		if (addSpringProxy) {
			proxiedInterfaces[index] = SpringProxy.class;
			index++;
		}
		if (addAdvised) {
			proxiedInterfaces[index] = Advised.class;
			index++;
		}
		if (addDecoratingProxy) {
			proxiedInterfaces[index] = DecoratingProxy.class;
		}
		return proxiedInterfaces;
	}
	
	/**
	 * Finds any {@link #equals} or {@link #hashCode} method that may be defined
	 * on the supplied set of interfaces.
	 * @param proxiedInterfaces the interfaces to introspect
	 */
	private void findDefinedEqualsAndHashCodeMethods(Class<?>[] proxiedInterfaces) {
		for (Class<?> proxiedInterface : proxiedInterfaces) {
			Method[] methods = proxiedInterface.getDeclaredMethods();
			for (Method method : methods) {
				if (AopUtils.isEqualsMethod(method)) {
					this.equalsDefined = true;
				}
				if (AopUtils.isHashCodeMethod(method)) {
					this.hashCodeDefined = true;
				}
				if (this.equalsDefined && this.hashCodeDefined) {
					return;
				}
			}
		}
	}
}