jspwiki-main/src/main/java/org/apache/wiki/auth/Authorizer.java

/* 
    Licensed to the Apache Software Foundation (ASF) under one
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    to you under the Apache License, Version 2.0 (the
    "License"); you may not use this file except in compliance
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       http://www.apache.org/licenses/LICENSE-2.0

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 */
package org.apache.wiki.auth;

import org.apache.wiki.WikiSession;
import org.apache.wiki.api.core.Engine;

import java.security.Principal;
import java.util.Properties;


/**
 * Interface for service providers of authorization information. After a user successfully logs in, the
 * {@link org.apache.wiki.auth.AuthenticationManager} consults the configured Authorizer to determine which additional
 * {@link org.apache.wiki.auth.authorize.Role} principals should be added to the user's WikiSession. To determine which roles should be
 * injected, the Authorizer is queried for the roles it knows about by calling {@link org.apache.wiki.auth.Authorizer#getRoles()}. Then,
 * each role returned by the Authorizer is tested by calling {@link org.apache.wiki.auth.Authorizer#isUserInRole(WikiSession, Principal)}.
 * If this check fails, and the Authorizer is of type WebAuthorizer, AuthenticationManager checks the role again by calling
 * {@link org.apache.wiki.auth.authorize.WebAuthorizer#isUserInRole(javax.servlet.http.HttpServletRequest, Principal)}).
 * Any roles that pass the test are injected into the Subject by firing appropriate authentication events.
 * 
 * @since 2.3
 */
public interface Authorizer {

    /**
     * Returns an array of role Principals this Authorizer knows about. This method will always return an array; an implementing class may
     * choose to return an zero-length array if it has no ability to identify the roles under its control.
     * 
     * @return an array of Principals representing the roles
     */
    Principal[] getRoles();

    /**
     * Looks up and returns a role Principal matching a given String. If a matching role cannot be found, this method returns
     * <code>null</code>. Note that it may not always be feasible for an Authorizer implementation to return a role Principal.
     * 
     * @param role the name of the role to retrieve
     * @return the role Principal
     */
    Principal findRole( String role );

    /**
     * Initializes the authorizer.
     * 
     * @param engine the current wiki engine
     * @param props the wiki engine initialization properties
     * @throws WikiSecurityException if the Authorizer could not be initialized
     */
    void initialize( Engine engine, Properties props ) throws WikiSecurityException;

    /**
     * Determines whether the Subject associated with a WikiSession is in a particular role. This method takes two parameters: the
     * WikiSession containing the subject and the desired role ( which may be a Role or a Group). If either parameter is <code>null</code>,
     * this method must return <code>false</code>.
     * 
     * @param session the current WikiSession
     * @param role the role to check
     * @return <code>true</code> if the user is considered to be in the role, <code>false</code> otherwise
     */
    boolean isUserInRole( WikiSession session, Principal role );

}