/*
 * Copyright 2002-2018 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 org.springframework.aop.framework;

import java.io.Closeable;

import org.springframework.beans.factory.Aware;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.Ordered;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;

Base class with common functionality for proxy processors, in particular ClassLoader management and the evaluateProxyInterfaces algorithm. 
Author:
Juergen Hoeller
See Also:
AbstractAdvisingBeanPostProcessor
AbstractAutoProxyCreator
Since:
4.1/**
 * Base class with common functionality for proxy processors, in particular
 * ClassLoader management and the {@link #evaluateProxyInterfaces} algorithm.
 *
 * @author Juergen Hoeller
 * @since 4.1
 * @see AbstractAdvisingBeanPostProcessor
 * @see org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator
 */
@SuppressWarnings("serial")
public class ProxyProcessorSupport extends ProxyConfig implements Ordered, BeanClassLoaderAware, AopInfrastructureBean {

	
This should run after all other processors, so that it can just add
an advisor to existing proxies rather than double-proxy.
/**
	 * This should run after all other processors, so that it can just add
	 * an advisor to existing proxies rather than double-proxy.
	 */
	private int order = Ordered.LOWEST_PRECEDENCE;

	@Nullable
	private ClassLoader proxyClassLoader = ClassUtils.getDefaultClassLoader();

	private boolean classLoaderConfigured = false;


	
Set the ordering which will apply to this processor's implementation of Ordered, used when applying multiple processors. 
The default value is Ordered.LOWEST_PRECEDENCE, meaning non-ordered. 
Params:
order – the ordering value/**
	 * Set the ordering which will apply to this processor's implementation
	 * of {@link Ordered}, used when applying multiple processors.
	 * <p>The default value is {@code Ordered.LOWEST_PRECEDENCE}, meaning non-ordered.
	 * @param order the ordering value
	 */
	public void setOrder(int order) {
		this.order = order;
	}

	@Override
	public int getOrder() {
		return this.order;
	}

	
Set the ClassLoader to generate the proxy class in.
Default is the bean ClassLoader, i.e. the ClassLoader used by the containing BeanFactory for loading all bean classes. This can be overridden here for specific proxies. /**
	 * Set the ClassLoader to generate the proxy class in.
	 * <p>Default is the bean ClassLoader, i.e. the ClassLoader used by the containing
	 * {@link org.springframework.beans.factory.BeanFactory} for loading all bean classes.
	 * This can be overridden here for specific proxies.
	 */
	public void setProxyClassLoader(@Nullable ClassLoader classLoader) {
		this.proxyClassLoader = classLoader;
		this.classLoaderConfigured = (classLoader != null);
	}

	
Return the configured proxy ClassLoader for this processor.
/**
	 * Return the configured proxy ClassLoader for this processor.
	 */
	@Nullable
	protected ClassLoader getProxyClassLoader() {
		return this.proxyClassLoader;
	}

	@Override
	public void setBeanClassLoader(ClassLoader classLoader) {
		if (!this.classLoaderConfigured) {
			this.proxyClassLoader = classLoader;
		}
	}


	
Check the interfaces on the given bean class and apply them to the ProxyFactory, if appropriate. 
Calls isConfigurationCallbackInterface and isInternalLanguageInterface to filter for reasonable proxy interfaces, falling back to a target-class proxy otherwise. 
Params:
beanClass – the class of the bean
proxyFactory – the ProxyFactory for the bean/**
	 * Check the interfaces on the given bean class and apply them to the {@link ProxyFactory},
	 * if appropriate.
	 * <p>Calls {@link #isConfigurationCallbackInterface} and {@link #isInternalLanguageInterface}
	 * to filter for reasonable proxy interfaces, falling back to a target-class proxy otherwise.
	 * @param beanClass the class of the bean
	 * @param proxyFactory the ProxyFactory for the bean
	 */
	protected void evaluateProxyInterfaces(Class<?> beanClass, ProxyFactory proxyFactory) {
		Class<?>[] targetInterfaces = ClassUtils.getAllInterfacesForClass(beanClass, getProxyClassLoader());
		boolean hasReasonableProxyInterface = false;
		for (Class<?> ifc : targetInterfaces) {
			if (!isConfigurationCallbackInterface(ifc) && !isInternalLanguageInterface(ifc) &&
					ifc.getMethods().length > 0) {
				hasReasonableProxyInterface = true;
				break;
			}
		}
		if (hasReasonableProxyInterface) {
			// Must allow for introductions; can't just set interfaces to the target's interfaces only.
			for (Class<?> ifc : targetInterfaces) {
				proxyFactory.addInterface(ifc);
			}
		}
		else {
			proxyFactory.setProxyTargetClass(true);
		}
	}

	
Determine whether the given interface is just a container callback and
therefore not to be considered as a reasonable proxy interface.
If no reasonable proxy interface is found for a given bean, it will get
proxied with its full target class, assuming that as the user's intention.
Params:
ifc – the interface to check
Returns:
whether the given interface is just a container callback/**
	 * Determine whether the given interface is just a container callback and
	 * therefore not to be considered as a reasonable proxy interface.
	 * <p>If no reasonable proxy interface is found for a given bean, it will get
	 * proxied with its full target class, assuming that as the user's intention.
	 * @param ifc the interface to check
	 * @return whether the given interface is just a container callback
	 */
	protected boolean isConfigurationCallbackInterface(Class<?> ifc) {
		return (InitializingBean.class == ifc || DisposableBean.class == ifc || Closeable.class == ifc ||
				AutoCloseable.class == ifc || ObjectUtils.containsElement(ifc.getInterfaces(), Aware.class));
	}

	
Determine whether the given interface is a well-known internal language interface
and therefore not to be considered as a reasonable proxy interface.
If no reasonable proxy interface is found for a given bean, it will get
proxied with its full target class, assuming that as the user's intention.
Params:
ifc – the interface to check
Returns:
whether the given interface is an internal language interface/**
	 * Determine whether the given interface is a well-known internal language interface
	 * and therefore not to be considered as a reasonable proxy interface.
	 * <p>If no reasonable proxy interface is found for a given bean, it will get
	 * proxied with its full target class, assuming that as the user's intention.
	 * @param ifc the interface to check
	 * @return whether the given interface is an internal language interface
	 */
	protected boolean isInternalLanguageInterface(Class<?> ifc) {
		return (ifc.getName().equals("groovy.lang.GroovyObject") ||
				ifc.getName().endsWith(".cglib.proxy.Factory") ||
				ifc.getName().endsWith(".bytebuddy.MockAccess"));
	}

}