001    /*
002     * Copyright (c) OSGi Alliance (2001, 2008). All Rights Reserved.
003     *
004     * Licensed under the Apache License, Version 2.0 (the "License");
005     * you may not use this file except in compliance with the License.
006     * You may obtain a copy of the License at
007     *
008     *      http://www.apache.org/licenses/LICENSE-2.0
009     *
010     * Unless required by applicable law or agreed to in writing, software
011     * distributed under the License is distributed on an "AS IS" BASIS,
012     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013     * See the License for the specific language governing permissions and
014     * limitations under the License.
015     */
016    package org.osgi.service.useradmin;
017    
018    /**
019     * The <code>Authorization</code> interface encapsulates an authorization context
020     * on which bundles can base authorization decisions, where appropriate.
021     * <p>
022     * Bundles associate the privilege to access restricted resources or operations
023     * with roles. Before granting access to a restricted resource or operation, a
024     * bundle will check if the <code>Authorization</code> object passed to it possess
025     * the required role, by calling its <code>hasRole</code> method.
026     * <p>
027     * Authorization contexts are instantiated by calling the
028     * {@link UserAdmin#getAuthorization} method.
029     * 
030     * <p>
031     * <i>Trusting Authorization objects </i>
032     * <p>
033     * There are no restrictions regarding the creation of <code>Authorization</code>
034     * objects. Hence, a service must only accept <code>Authorization</code> objects
035     * from bundles that has been authorized to use the service using code based (or
036     * Java 2) permissions.
037     * 
038     * <p>
039     * In some cases it is useful to use <code>ServicePermission</code> to do the code
040     * based access control. A service basing user access control on
041     * <code>Authorization</code> objects passed to it, will then require that a
042     * calling bundle has the <code>ServicePermission</code> to get the service in
043     * question. This is the most convenient way. The OSGi environment will do the
044     * code based permission check when the calling bundle attempts to get the
045     * service from the service registry.
046     * <p>
047     * Example: A servlet using a service on a user's behalf. The bundle with the
048     * servlet must be given the <code>ServicePermission</code> to get the Http
049     * Service.
050     * <p>
051     * However, in some cases the code based permission checks need to be more
052     * fine-grained. A service might allow all bundles to get it, but require
053     * certain code based permissions for some of its methods.
054     * <p>
055     * Example: A servlet using a service on a user's behalf, where some service
056     * functionality is open to anyone, and some is restricted by code based
057     * permissions. When a restricted method is called (e.g., one handing over an
058     * <code>Authorization</code> object), the service explicitly checks that the
059     * calling bundle has permission to make the call.
060     * 
061     * @version $Revision: 5673 $
062     */
063    public interface Authorization {
064            /**
065             * Gets the name of the {@link User} that this <code>Authorization</code>
066             * context was created for.
067             * 
068             * @return The name of the {@link User} object that this
069             *         <code>Authorization</code> context was created for, or
070             *         <code>null</code> if no user was specified when this
071             *         <code>Authorization</code> context was created.
072             */
073            public String getName();
074    
075            /**
076             * Checks if the role with the specified name is implied by this
077             * <code>Authorization</code> context.
078             * <p>
079             * 
080             * Bundles must define globally unique role names that are associated with
081             * the privilege of accessing restricted resources or operations. Operators
082             * will grant users access to these resources, by creating a {@link Group}
083             * object for each role and adding {@link User} objects to it.
084             * 
085             * @param name The name of the role to check for.
086             * 
087             * @return <code>true</code> if this <code>Authorization</code> context implies
088             *         the specified role, otherwise <code>false</code>.
089             */
090            public boolean hasRole(String name);
091    
092            /**
093             * Gets the names of all roles implied by this <code>Authorization</code>
094             * context.
095             * 
096             * @return The names of all roles implied by this
097             *         <code>Authorization</code> context, or <code>null</code> if no roles
098             *         are in the context. The predefined role <code>user.anyone</code>
099             *         will not be included in this list.
100             */
101            public String[] getRoles();
102    }