advisedsupport.java

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/*
 * 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.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.aopalliance.aop.Advice;

import org.springframework.aop.Advisor;
import org.springframework.aop.DynamicIntroductionAdvice;
import org.springframework.aop.IntroductionAdvisor;
import org.springframework.aop.IntroductionInfo;
import org.springframework.aop.TargetSource;
import org.springframework.aop.support.DefaultIntroductionAdvisor;
import org.springframework.aop.support.DefaultPointcutAdvisor;
import org.springframework.aop.target.EmptyTargetSource;
import org.springframework.aop.target.SingletonTargetSource;
import org.springframework.core.CollectionFactory;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;

/**
 * Base class for AOP proxy configuration managers.
 * These are not themselves AOP proxies, but subclasses of this class are
 * normally factories from which AOP proxy instances are obtained directly.
 *
 * <p>This class frees subclasses of the housekeeping of Advices
 * and Advisors, but doesn't actually implement proxy creation
 * methods, which are provided by subclasses.
 *
 * <p>This class is serializable; subclasses need not be.
 * This class is used to hold snapshots of proxies.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see org.springframework.aop.framework.AopProxy
 */
public class AdvisedSupport extends ProxyConfig implements Advised {

	/** use serialVersionUID from Spring 2.0 for interoperability */
	private static final long serialVersionUID = 2651364800145442165L;


	/**
	 * Canonical TargetSource when there's no target, and behavior is
	 * supplied by the advisors.
	 */
	public static final TargetSource EMPTY_TARGET_SOURCE = EmptyTargetSource.INSTANCE;


	/** Package-protected to allow direct access for efficiency */
	TargetSource targetSource = EMPTY_TARGET_SOURCE;

	/** The AdvisorChainFactory to use */
	transient AdvisorChainFactory advisorChainFactory;

	/** Cache with Method as key and advisor chain List as value */
	private transient Map methodCache;

	/**
	 * Interfaces to be implemented by the proxy. Held in List to keep the order
	 * of registration, to create JDK proxy with specified order of interfaces.
	 */
	private List interfaces = new ArrayList();

	/**
	 * List of Advisors. If an Advice is added, it will be wrapped
	 * in an Advisor before being added to this List.
	 */
	private List advisors = new LinkedList();

	/**
	 * Array updated on changes to the advisors list, which is easier
	 * to manipulate internally.
	 */
	private Advisor[] advisorArray = new Advisor[0];


	/**
	 * No-arg constructor for use as a JavaBean.
	 */
	public AdvisedSupport() {
		initDefaultAdvisorChainFactory();
	}

	/**
	 * Create a AdvisedSupport instance with the given parameters.
	 * @param interfaces the proxied interfaces
	 */
	public AdvisedSupport(Class[] interfaces) {
		this();
		setInterfaces(interfaces);
	}

	/**
	 * Initialize the default AdvisorChainFactory.
	 */
	private void initDefaultAdvisorChainFactory() {
		setAdvisorChainFactory(new DefaultAdvisorChainFactory());
		this.methodCache = CollectionFactory.createIdentityMapIfPossible(32);
	}


	/**
	 * Set the given object as target.
	 * Will create a SingletonTargetSource for the object.
	 * @see #setTargetSource
	 * @see org.springframework.aop.target.SingletonTargetSource
	 */
	public void setTarget(Object target) {
		setTargetSource(new SingletonTargetSource(target));
	}

	public void setTargetSource(TargetSource targetSource) {
		this.targetSource = (targetSource != null ? targetSource : EMPTY_TARGET_SOURCE);
	}

	public TargetSource getTargetSource() {
		return this.targetSource;
	}

	/**
	 * Set a target class to be proxied, indicating that the proxy
	 * should be castable to the given class.
	 * <p>Internally, an {@link org.springframework.aop.target.EmptyTargetSource}
	 * for the given target class will be used. The kind of proxy needed
	 * will be determined on actual creation of the proxy.
	 * <p>This is a replacement for setting a "targetSource" or "target",
	 * for the case where we want a proxy based on a target class
	 * (which can be an interface or a concrete class) without having
	 * a fully capable TargetSource available.
	 * @see #setTargetSource
	 * @see #setTarget
	 */
	public void setTargetClass(Class targetClass) {
		this.targetSource = EmptyTargetSource.forClass(targetClass);
	}

	public Class getTargetClass() {
		return this.targetSource.getTargetClass();
	}

	/**
	 * Set the advisor chain factory to use.
	 * <p>Default is a {@link DefaultAdvisorChainFactory}.
	 */
	public void setAdvisorChainFactory(AdvisorChainFactory advisorChainFactory) {
		Assert.notNull(advisorChainFactory, "AdvisorChainFactory must not be null");
		this.advisorChainFactory = advisorChainFactory;
	}

	/**
	 * Return the advisor chain factory to use (never <code>null</code>).
	 */
	public AdvisorChainFactory getAdvisorChainFactory() {
		return this.advisorChainFactory;
	}


	/**
	 * Set the interfaces to be proxied.
	 */
	public void setInterfaces(Class[] interfaces) {
		Assert.notNull(interfaces, "Interfaces must not be null");
		this.interfaces.clear();
		for (int i = 0; i < interfaces.length; i++) {
			addInterface(interfaces[i]);
		}
	}

	/**
	 * Add a new proxied interface.
	 * @param intf the additional interface to proxy
	 */
	public void addInterface(Class intf) {
		Assert.notNull(intf, "Interface must not be null");
		if (!intf.isInterface()) {
			throw new IllegalArgumentException("[" + intf.getName() + "] is not an interface");
		}
		if (!this.interfaces.contains(intf)) {
			this.interfaces.add(intf);
			adviceChanged();
		}
	}

	/**
	 * Remove a proxied interface.
	 * <p>Does nothing if the given interface isn't proxied.
	 * @param intf the interface to remove from the proxy
	 * @return <code>true</code> if the interface was removed; <code>false</code>
	 * if the interface was not found and hence could not be removed
	 */
	public boolean removeInterface(Class intf) {
		return this.interfaces.remove(intf);
	}

	public Class[] getProxiedInterfaces() {
		return (Class[]) this.interfaces.toArray(new Class[this.interfaces.size()]);
	}

	public boolean isInterfaceProxied(Class intf) {
		for (Iterator it = this.interfaces.iterator(); it.hasNext();) {
			Class proxyIntf = (Class) it.next();
			if (intf.isAssignableFrom(proxyIntf)) {
				return true;
			}
		}
		return false;
	}


	public final Advisor[] getAdvisors() {
		return this.advisorArray;
	}

	public void addAdvisor(Advisor advisor) {
		int pos = this.advisors.size();
		addAdvisor(pos, advisor);
	}

	public void addAdvisor(int pos, Advisor advisor) throws AopConfigException {
		if (advisor instanceof IntroductionAdvisor) {
			validateIntroductionAdvisor((IntroductionAdvisor) advisor);
		}
		addAdvisorInternal(pos, advisor);
	}

	public boolean removeAdvisor(Advisor advisor) {
		int index = indexOf(advisor);
		if (index == -1) {
			return false;
		}
		else {
			removeAdvisor(index);
			return true;
		}
	}

	public void removeAdvisor(int index) throws AopConfigException {
		if (isFrozen()) {
			throw new AopConfigException("Cannot remove Advisor: Configuration is frozen.");
		}
		if (index < 0 || index > this.advisors.size() - 1) {
			throw new AopConfigException("Advisor index " + index + " is out of bounds: " +
					"This configuration only has " + this.advisors.size() + " advisors.");
		}

		Advisor advisor = (Advisor) this.advisors.get(index);
		if (advisor instanceof IntroductionAdvisor) {
			IntroductionAdvisor ia = (IntroductionAdvisor) advisor;
			// We need to remove introduction interfaces.
			for (int j = 0; j < ia.getInterfaces().length; j++) {
				removeInterface(ia.getInterfaces()[j]);
			}
		}

		this.advisors.remove(index);