/*
 * 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.support;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;

import org.aopalliance.aop.Advice;

import org.springframework.aop.ClassFilter;
import org.springframework.aop.DynamicIntroductionAdvice;
import org.springframework.aop.IntroductionAdvisor;
import org.springframework.aop.IntroductionInfo;
import org.springframework.core.Ordered;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;

/**
 * Simple {@link org.springframework.aop.IntroductionAdvisor} implementation
 * that by default applies to any class.
 *
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @since 11.11.2003
 */
public class DefaultIntroductionAdvisor implements IntroductionAdvisor, ClassFilter, Ordered, Serializable {

	private final Advice advice;
	
	private final Set interfaces = new HashSet();

	private int order = Integer.MAX_VALUE;


	/**
	 * Create a DefaultIntroductionAdvisor for the given advice.
	 * @param advice the Advice to apply (may implement the
	 * {@link org.springframework.aop.IntroductionInfo} interface)
	 * @see #addInterface
	 */
	public DefaultIntroductionAdvisor(Advice advice) {
		this(advice, (advice instanceof IntroductionInfo ? (IntroductionInfo) advice : null));
	}

	/**
	 * Create a DefaultIntroductionAdvisor for the given advice.
	 * @param advice the Advice to apply
	 * @param introductionInfo the IntroductionInfo that describes
	 * the interface to introduce (may be <code>null</code>)
	 */
	public DefaultIntroductionAdvisor(Advice advice, IntroductionInfo introductionInfo) {
		Assert.notNull(advice, "Advice must not be null");
		this.advice = advice;
		if (introductionInfo != null) {
			Class[] introducedInterfaces = introductionInfo.getInterfaces();
			if (introducedInterfaces.length == 0) {
				throw new IllegalArgumentException("IntroductionAdviceSupport implements no interfaces");
			}
			for (int i = 0; i < introducedInterfaces.length; i++) {
				addInterface(introducedInterfaces[i]);
			}
		}
	}

	/**
	 * Create a DefaultIntroductionAdvisor for the given advice.
	 * @param advice the Advice to apply
	 * @param intf the interface to introduce
	 */
	public DefaultIntroductionAdvisor(DynamicIntroductionAdvice advice, Class intf) {
		Assert.notNull(advice, "Advice must not be null");
		this.advice = advice;
		addInterface(intf);
	}


	/**
	 * Add the specified interface to the list of interfaces to introduce.
	 * @param intf the interface to introduce
	 */
	public void addInterface(Class intf) {
		Assert.notNull(intf, "Interface must not be null");
		if (!intf.isInterface()) {
			throw new IllegalArgumentException("Specified class [" + intf.getName() + "] must be an interface");
		}
		this.interfaces.add(intf);
	}

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

	public void validateInterfaces() throws IllegalArgumentException {
		for (Iterator it = this.interfaces.iterator(); it.hasNext();) {
			Class ifc = (Class) it.next();
			if (this.advice instanceof DynamicIntroductionAdvice &&
					!((DynamicIntroductionAdvice) this.advice).implementsInterface(ifc)) {
			 throw new IllegalArgumentException("DynamicIntroductionAdvice [" + this.advice + "] " +
					 "does not implement interface [" + ifc.getName() + "] specified for introduction");
			}
		}
	}


	public void setOrder(int order) {
		this.order = order;
	}

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


	public Advice getAdvice() {
		return this.advice;
	}

	public boolean isPerInstance() {
		return true;
	}

	public ClassFilter getClassFilter() {
		return this;
	}

	public boolean matches(Class clazz) {
		return true;
	}


	public boolean equals(Object other) {
		if (this == other) {
			return true;
		}
		if (!(other instanceof DefaultIntroductionAdvisor)) {
			return false;
		}
		DefaultIntroductionAdvisor otherAdvisor = (DefaultIntroductionAdvisor) other;
		return (this.advice.equals(otherAdvisor.advice) && this.interfaces.equals(otherAdvisor.interfaces));
	}

	public int hashCode() {
		return this.advice.hashCode() * 13 + this.interfaces.hashCode();
	}

	public String toString() {
		return ClassUtils.getShortName(getClass()) + ": advice [" + this.advice + "]; interfaces " +
				ClassUtils.classNamesToString(this.interfaces);
	}

}