/*
 * Copyright 2005-2010 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.wamblee.security.authorization;

import org.wamblee.security.authentication.UserAccessor;
import org.wamblee.security.authentication.UserAdministration;

/**
 * Service to determine if access to a certain resource is allowed.
 * 
 * @author Erik Brakkee
 */
public interface AuthorizationService {

    /**
     * Checks whether an operation is allowed on a resource.
     * 
     * @param aResource
     *            Resource.
     * @param aOperation
     *            Operation.
     * 
     * @return Checks whether the operation is allowed on a resource.
     */
    boolean isAllowed(Object aResource, Operation aOperation);

    /**
     * Checks if the given operation is allowed on the resource.
     * 
     * @param <T>
     *            Type of resource
     * @param aResource
     *            Resource.
     * @param aOperation
     *            Operation.
     * @return Resource passed in in case access is allowed
     * @throws AuthorizationException
     *             In case access is denied.
     */
    <T> T check(T aResource, Operation aOperation);

    /**
     * Gets the authorization rules.
     * 
     * @return Rules.
     */
    AuthorizationRule[] getRules();

    /**
     * Appends a new authorization rule to the end.
     * 
     * @param aRule
     *            Rule to append.
     */
    void appendRule(AuthorizationRule aRule);

    /**
     * Removes a rule.
     * 
     * @param aIndex
     *            Index of the rule to remove.
     */
    void removeRule(int aIndex);

    /**
     * Inserts a rule.
     * 
     * @param aIndex
     *            Index of the position of the rule after insertion.
     * @param aRule
     *            Rule to insert.
     */
    void insertRuleAfter(int aIndex, AuthorizationRule aRule);

    /**
     * Sets the user accessor so that the authorization service can get access
     * to the logged in user.
     * 
     * @param aUserAccessor
     *            User accessor.
     */
    void setUserAccessor(UserAccessor aUserAccessor);
    
    /**
     * Sets the user administration so that the authorization service can check 
     * information for the the current user.
     *  
     * @param aUserAdmin User administration. 
     */
    void setUserAdministration(UserAdministration aUserAdmin); 

}