/* 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.acegisecurity.vote;

import java.util.Iterator;

import org.acegisecurity.Authentication;
import org.acegisecurity.ConfigAttribute;
import org.acegisecurity.ConfigAttributeDefinition;

/**
 * <p>
 * Votes if any {@link ConfigAttribute#getAttribute()} starts with a prefix
 * indicating that it is a role. The default prefix string is <Code>ROLE_</code>,
 * but this may be overriden to any value. It may also be set to empty, which
 * means that essentially any attribute will be voted on. As described further
 * below, the effect of an empty prefix may not be quite desireable.
 * </p>
 * <p>
 * Abstains from voting if no configuration attribute commences with the role
 * prefix. Votes to grant access if there is an exact matching
 * {@link org.acegisecurity.GrantedAuthority} to a <code>ConfigAttribute</code>
 * starting with the role prefix. Votes to deny access if there is no exact
 * matching <code>GrantedAuthority</code> to a <code>ConfigAttribute</code>
 * starting with the role prefix.
 * </p>
 * <p>
 * An empty role prefix means that the voter will vote for every
 * ConfigAttribute. When there are different categories of ConfigAttributes
 * used, this will not be optimal since the voter will be voting for attributes
 * which do not represent roles. However, this option may be of some use when
 * using preexisting role names without a prefix, and no ability exists to
 * prefix them with a role prefix on reading them in, such as provided for
 * example in {@link org.acegisecurity.userdetails.jdbc.JdbcDaoImpl}.
 * </p>
 * <p>
 * All comparisons and prefixes are case sensitive.
 * </p>
 * 
 * @author Ben Alex
 * @author colin sampaleanu
 * @version $Id: RoleVoter.java 1948 2007-08-25 00:15:30Z benalex $
 */
public class RoleVoter implements AccessDecisionVoter {
	// ~ Instance fields
	// ================================================================================================

	private String rolePrefix = "ROLE_";

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

	public String getRolePrefix() {
		return rolePrefix;
	}

	/**
	 * Allows the default role prefix of <code>ROLE_</code> to be overriden.
	 * May be set to an empty value, although this is usually not desireable.
	 * 
	 * @param rolePrefix the new prefix
	 */
	public void setRolePrefix(String rolePrefix) {
		this.rolePrefix = rolePrefix;
	}

	public boolean supports(ConfigAttribute attribute) {
		if ((attribute.getAttribute() != null) && attribute.getAttribute().startsWith(getRolePrefix())) {
			return true;
		}
		else {
			return false;
		}
	}

	/**
	 * This implementation supports any type of class, because it does not query
	 * the presented secure object.
	 * 
	 * @param clazz the secure object
	 * 
	 * @return always <code>true</code>
	 */
	public boolean supports(Class clazz) {
		return true;
	}

	public int vote(Authentication authentication, Object object, ConfigAttributeDefinition config) {
		int result = ACCESS_ABSTAIN;
		Iterator iter = config.getConfigAttributes();

		while (iter.hasNext()) {
			ConfigAttribute attribute = (ConfigAttribute) iter.next();

			if (this.supports(attribute)) {
				result = ACCESS_DENIED;

				// Attempt to find a matching granted authority
				for (int i = 0; i < authentication.getAuthorities().length; i++) {
					if (attribute.getAttribute().equals(authentication.getAuthorities()[i].getAuthority())) {
						return ACCESS_GRANTED;
					}
				}
			}
		}

		return result;
	}
}
