/*
 * Copyright 2002-2004 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;

/**
 * Simple IntroductionAdvisor implementation that by default applies to any class.
 * @author Rod Johnson
 * @since 11-Nov-2003
 */
public class DefaultIntroductionAdvisor implements IntroductionAdvisor, ClassFilter, Ordered, Serializable {

	/** use serialVersionUID from Spring 1.1 for interoperability */
	private static final long serialVersionUID = 1360502830817661569L;


	private int order = Integer.MAX_VALUE;

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


	public DefaultIntroductionAdvisor(Advice advice) {
		if (advice instanceof IntroductionInfo) {
			init(advice, (IntroductionInfo) advice);
		}
		else {
			this.advice = advice;
		}
	}
	
	public DefaultIntroductionAdvisor(DynamicIntroductionAdvice advice, Class clazz) {
		this.advice = advice;
		addInterface(clazz);
	}
	
	/**
	 * Wrap the given interceptor and introduce all interfaces.
	 */
	public DefaultIntroductionAdvisor(Advice advice, IntroductionInfo introductionInfo) {
		init(advice, introductionInfo);
	}
		
	private void init(Advice advice, IntroductionInfo introductionInfo) {
		this.advice = advice;
		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]);
		}
	}


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

	public int getOrder() {
		return order;
	}

	public void addInterface(Class intf) {
		this.interfaces.add(intf);
	}

	public ClassFilter getClassFilter() {
		return this;
	}

	public Advice getAdvice() {
		return advice;
	}

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


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

	/**
	 * Default for an introduction is per-instance interception.
	 */
	public boolean isPerInstance() {
		return true;
	}
	
	public void validateInterfaces() throws IllegalArgumentException {
		for (Iterator ut = this.interfaces.iterator(); ut.hasNext();) {
			Class intf = (Class) ut.next();
			if (!intf.isInterface()) {
			 throw new IllegalArgumentException("Class '" + intf.getName() +
																					"' is not an interface; cannot be used in an introduction");
			}
			if (this.advice instanceof DynamicIntroductionAdvice &&
					!((DynamicIntroductionAdvice) this.advice).implementsInterface(intf)) {
			 throw new IllegalArgumentException("IntroductionAdvice [" + this.advice + "] " +
					 "does not implement interface '" + intf.getName() + "' specified in introduction advice");
			}
		}
	}
	
	public String toString() {
		return "DefaultIntroductionAdvisor: interfaces=[" + AopUtils.interfacesString(this.interfaces) +
				"]; introductionInterceptor=[" + this.advice + "]";
	}

}
