/*
 * Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * 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.security.access.method;

import java.util.Collection;

import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.framework.AopProxyUtils;
import org.springframework.security.access.ConfigAttribute;

/**
 * Abstract implementation of <tt>MethodSecurityMetadataSource</tt> which resolves the
 * secured object type to a MethodInvocation.
 *
 * @author Ben Alex
 * @author Luke Taylor
 */
public abstract class AbstractMethodSecurityMetadataSource implements
		MethodSecurityMetadataSource {

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

	// ~ Methods
	// ========================================================================================================

	public final Collection<ConfigAttribute> getAttributes(Object object) {
		if (object instanceof MethodInvocation) {
			MethodInvocation mi = (MethodInvocation) object;
			Object target = mi.getThis();
			Class<?> targetClass = null;

			if (target != null) {
				targetClass = target instanceof Class<?> ? (Class<?>) target
						: AopProxyUtils.ultimateTargetClass(target);
			}
			Collection<ConfigAttribute> attrs = getAttributes(mi.getMethod(), targetClass);
			if (attrs != null && !attrs.isEmpty()) {
				return attrs;
			}
			if (target != null && !(target instanceof Class<?>)) {
				attrs = getAttributes(mi.getMethod(), target.getClass());
			}
			return attrs;
		}

		throw new IllegalArgumentException("Object must be a non-null MethodInvocation");
	}

	public final boolean supports(Class<?> clazz) {
		return (MethodInvocation.class.isAssignableFrom(clazz));
	}
}
