proxyfactorybean.java

Spring API核心源代码 Spring API核心源代码 Spring API核心源代码

/*
 * 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.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.aopalliance.aop.Advice;
import org.aopalliance.intercept.Interceptor;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.aop.Advisor;
import org.springframework.aop.TargetSource;
import org.springframework.aop.framework.adapter.AdvisorAdapterRegistry;
import org.springframework.aop.framework.adapter.GlobalAdvisorAdapterRegistry;
import org.springframework.aop.framework.adapter.UnknownAdviceTypeException;
import org.springframework.aop.target.SingletonTargetSource;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanFactoryUtils;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.ListableBeanFactory;
import org.springframework.core.OrderComparator;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;

/**
 * {@link org.springframework.beans.factory.FactoryBean} implementation that builds an
 * AOP proxy based on beans in Spring {@link org.springframework.beans.factory.BeanFactory}.
 *
 * <p>{@link org.aopalliance.intercept.MethodInterceptor MethodInterceptors} and
 * {@link org.springframework.aop.Advisor Advisors} are identified by a list of bean
 * names in the current bean factory, specified through the "interceptorNames" property.
 * The last entry in the list can be the name of a target bean or a
 * {@link org.springframework.aop.TargetSource}; however, it is normally preferable
 * to use the "targetName"/"target"/"targetSource" properties instead.
 *
 * <p>Global interceptors and advisors can be added at the factory level. The specified
 * ones are expanded in an interceptor list where an "xxx*" entry is included in the
 * list, matching the given prefix with the bean names (e.g. "global*" would match
 * both "globalBean1" and "globalBean2", "*" all defined interceptors). The matching
 * interceptors get applied according to their returned order value, if they implement
 * the {@link org.springframework.core.Ordered} interface.
 *
 * <p>Creates a JDK proxy when proxy interfaces are given, and a CGLIB proxy for the
 * actual target class if not. Note that the latter will only work if the target class
 * does not have final methods, as a dynamic subclass will be created at runtime.
 *
 * <p>It's possible to cast a proxy obtained from this factory to {@link Advised},
 * or to obtain the ProxyFactoryBean reference and programmatically manipulate it.
 * This won't work for existing prototype references, which are independent. However,
 * it will work for prototypes subsequently obtained from the factory. Changes to
 * interception will work immediately on singletons (including existing references).
 * However, to change interfaces or target it's necessary to obtain a new instance
 * from the factory. This means that singleton instances obtained from the factory
 * do not have the same object identity. However, they do have the same interceptors
 * and target, and changing any reference will change all objects.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see #setInterceptorNames
 * @see #setProxyInterfaces
 * @see org.aopalliance.intercept.MethodInterceptor
 * @see org.springframework.aop.Advisor
 * @see Advised
 */
public class ProxyFactoryBean extends ProxyCreatorSupport
		implements FactoryBean, BeanClassLoaderAware, BeanFactoryAware {

	/**
	 * This suffix in a value in an interceptor list indicates to expand globals.
	 */
	public static final String GLOBAL_SUFFIX = "*";


	protected final Log logger = LogFactory.getLog(getClass());

	private String[] interceptorNames;
	
	private String targetName;

	private boolean autodetectInterfaces = true;

	private boolean singleton = true;

	private AdvisorAdapterRegistry advisorAdapterRegistry = GlobalAdvisorAdapterRegistry.getInstance();

	/**
	 * Indicates whether the proxy should be frozen before creation.
	 */
	private boolean freezeProxy = false;

	private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();

	/**
	 * Owning bean factory, which cannot be changed after this
	 * object is initialized.
	 */
	private BeanFactory beanFactory;

	/** Whether the advisor chain has already been initialized */
	private boolean advisorChainInitialized = false;

	/** If this is a singleton, the cached singleton proxy instance */
	private Object singletonInstance;


	/**
	 * Set the names of the interfaces we're proxying. If no interface
	 * is given, a CGLIB for the actual class will be created.
	 * <p>This is essentially equivalent to the "setInterfaces" method,
	 * but mirrors TransactionProxyFactoryBean's "setProxyInterfaces".
	 * @see #setInterfaces
	 * @see AbstractSingletonProxyFactoryBean#setProxyInterfaces
	 */
	public void setProxyInterfaces(Class[] proxyInterfaces) throws ClassNotFoundException {
		setInterfaces(proxyInterfaces);
	}

	/**
	 * Set the list of Advice/Advisor bean names. This must always be set
	 * to use this factory bean in a bean factory.
	 * <p>The referenced beans should be of type Interceptor, Advisor or Advice
	 * The last entry in the list can be the name of any bean in the factory.
	 * If it's neither an Advice nor an Advisor, a new SingletonTargetSource
	 * is added to wrap it. Such a target bean cannot be used if the "target"
	 * or "targetSource" or "targetName" property is set, in which case the
	 * "interceptorNames" array must contain only Advice/Advisor bean names.
	 * @see org.aopalliance.intercept.MethodInterceptor
	 * @see org.springframework.aop.Advisor
	 * @see org.aopalliance.aop.Advice
	 * @see org.springframework.aop.target.SingletonTargetSource
	 */
	public void setInterceptorNames(String[] interceptorNames) {
		this.interceptorNames = interceptorNames;
	}

	/**
	 * Set the name of the target bean. This is an alternative to specifying
	 * the target name at the end of the "interceptorNames" array.
	 * <p>You can also specify a target object or a TargetSource object
	 * directly, via the "target"/"targetSource" property, respectively.
	 * @see #setInterceptorNames(String[])
	 * @see #setTarget(Object)
	 * @see #setTargetSource(org.springframework.aop.TargetSource)
	 */
	public void setTargetName(String targetName) {
		this.targetName = targetName;
	}

	/**
	 * Set whether to autodetect proxy interfaces if none specified.
	 * <p>Default is "true". Turn this flag off to create a CGLIB
	 * proxy for the full target class if no interfaces specified.
	 * @see #setProxyTargetClass
	 */
	public void setAutodetectInterfaces(boolean autodetectInterfaces) {
		this.autodetectInterfaces = autodetectInterfaces;
	}

	/**
	 * Set the value of the singleton property. Governs whether this factory
	 * should always return the same proxy instance (which implies the same target)
	 * or whether it should return a new prototype instance, which implies that
	 * the target and interceptors may be new instances also, if they are obtained
	 * from prototype bean definitions. This allows for fine control of
	 * independence/uniqueness in the object graph.
	 */
	public void setSingleton(boolean singleton) {
		this.singleton = singleton;
	}

	/**
	 * Specify the AdvisorAdapterRegistry to use.
	 * Default is the global AdvisorAdapterRegistry.
	 * @see org.springframework.aop.framework.adapter.GlobalAdvisorAdapterRegistry
	 */
	public void setAdvisorAdapterRegistry(AdvisorAdapterRegistry advisorAdapterRegistry) {
		this.advisorAdapterRegistry = advisorAdapterRegistry;
	}

	public void setFrozen(boolean frozen) {
		this.freezeProxy = frozen;
	}

	public void setBeanClassLoader(ClassLoader classLoader) {
		this.beanClassLoader = classLoader;
	}

	public void setBeanFactory(BeanFactory beanFactory) {
		this.beanFactory = beanFactory;
		checkInterceptorNames();
	}


	/**
	 * Return a proxy. Invoked when clients obtain beans from this factory bean.
	 * Create an instance of the AOP proxy to be returned by this factory.
	 * The instance will be cached for a singleton, and create on each call to
	 * <code>getObject()</code> for a proxy.
	 * @return a fresh AOP proxy reflecting the current state of this factory
	 */
	public Object getObject() throws BeansException {
		initializeAdvisorChain();
		if (isSingleton()) {
			return getSingletonInstance();
		}
		else {
			if (this.targetName == null) {
				logger.warn("Using non-singleton proxies with singleton targets is often undesirable." +
						"Enable prototype proxies by setting the 'targetName' property.");
			}
			return newPrototypeInstance();
		}
	}

	/**
	 * Return the type of the proxy. Will check the singleton instance if
	 * already created, else fall back to the proxy interface (in case of just
	 * a single one), the target bean type, or the TargetSource's target class.
	 * @see org.springframework.aop.TargetSource#getTargetClass
	 */
	public Class getObjectType() {
		synchronized (this) {
			if (this.singletonInstance != null) {
				return this.singletonInstance.getClass();
			}
		}
		Class[] ifcs = getProxiedInterfaces();
		if (ifcs.length == 1) {
			return ifcs[0];
		}
		else if (ifcs.length > 1) {
			return createCompositeInterface(ifcs);
		}
		else if (this.targetName != null && this.beanFactory != null) {
			return this.beanFactory.getType(this.targetName);
		}
		else {
			return getTargetClass();
		}
	}

	public boolean isSingleton() {
		return this.singleton;
	}


	/**
	 * Create a composite interface Class for the given interfaces,
	 * implementing the given interfaces in one single Class.
	 * <p>The default implementation builds a JDK proxy class for the
	 * given interfaces.
	 * @param interfaces the interfaces to merge
	 * @return the merged interface as Class
	 * @see java.lang.reflect.Proxy#getProxyClass
	 */
	protected Class createCompositeInterface(Class[] interfaces) {
		return ClassUtils.createCompositeInterface(interfaces, this.beanClassLoader);
	}

	/**
	 * Return the singleton instance of this class's proxy object,
	 * lazily creating it if it hasn't been created already.
	 * @return the shared singleton proxy
	 */
	private synchronized Object getSingletonInstance() {
		if (this.singletonInstance == null) {
			this.targetSource = freshTargetSource();
			if (this.autodetectInterfaces && getProxiedInterfaces().length == 0 && !isProxyTargetClass()) {
				// Rely on AOP infrastructure to tell us what interfaces to proxy.
				setInterfaces(ClassUtils.getAllInterfacesForClass(this.targetSource.getTargetClass()));
			}
			// Initialize the shared singleton instance.
			super.setFrozen(this.freezeProxy);
			this.singletonInstance = getProxy(createAopProxy());
		}
		return this.singletonInstance;
	}

	/**
	 * Create a new prototype instance of this class's created proxy object,
	 * backed by an independent AdvisedSupport configuration.
	 * @return a totally independent proxy, whose advice we may manipulate in isolation