001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    package org.apache.shiro.authc.pam;
020    
021    import org.apache.shiro.authc.*;
022    import org.apache.shiro.realm.Realm;
023    
024    import java.util.Collection;
025    
026    
027    /**
028     * Abstract base implementation for Shiro's concrete <code>AuthenticationStrategy</code>
029     * implementations.
030     *
031     * @author Jeremy Haile
032     * @author Les Hazlewood
033     * @since 0.9
034     */
035    public abstract class AbstractAuthenticationStrategy implements AuthenticationStrategy {
036    
037        /**
038         * Simply returns <code>new {@link org.apache.shiro.authc.SimpleAuthenticationInfo SimpleAuthenticationInfo}();</code>, which supports
039         * aggregating account data across realms.
040         */
041        public AuthenticationInfo beforeAllAttempts(Collection<? extends Realm> realms, AuthenticationToken token) throws AuthenticationException {
042            return new SimpleAuthenticationInfo();
043        }
044    
045        /**
046         * Simply returns the <code>aggregate</code> method argument, without modification.
047         */
048        public AuthenticationInfo beforeAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException {
049            return aggregate;
050        }
051    
052        /**
053         * Base implementation that will aggregate the specified <code>singleRealmInfo</code> into the
054         * <code>aggregateInfo</code> and then returns the aggregate.  Can be overridden by subclasses for custom behavior.
055         */
056        public AuthenticationInfo afterAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo singleRealmInfo, AuthenticationInfo aggregateInfo, Throwable t) throws AuthenticationException {
057            AuthenticationInfo info;
058            if (singleRealmInfo == null) {
059                info = aggregateInfo;
060            } else {
061                if (aggregateInfo == null) {
062                    info = singleRealmInfo;
063                } else {
064                    info = merge(singleRealmInfo, aggregateInfo);
065                }
066            }
067    
068            return info;
069        }
070    
071        /**
072         * Merges the specified <code>info</code> argument into the <code>aggregate</code> argument and then returns an
073         * aggregate for continued use throughout the login process.
074         * <p/>
075         * This implementation merely checks to see if the specified <code>aggregate</code> argument is an instance of
076         * {@link org.apache.shiro.authc.MergableAuthenticationInfo MergableAuthenticationInfo}, and if so, calls
077         * <code>aggregate.merge(info)</code>  If it is <em>not</em> an instance of
078         * <code>MergableAuthenticationInfo</code>, an {@link IllegalArgumentException IllegalArgumentException} is thrown.
079         * Can be overridden by subclasses for custom merging behavior if implementing the
080         * {@link org.apache.shiro.authc.MergableAuthenticationInfo MergableAuthenticationInfo} is not desired for some reason.
081         */
082        protected AuthenticationInfo merge(AuthenticationInfo info, AuthenticationInfo aggregate) {
083            if( aggregate instanceof MergableAuthenticationInfo ) {
084                ((MergableAuthenticationInfo)aggregate).merge(info);
085                return aggregate;
086            } else {
087                throw new IllegalArgumentException( "Attempt to merge authentication info from multiple realms, but aggregate " +
088                          "AuthenticationInfo is not of type MergableAuthenticationInfo." );
089            }
090        }
091    
092        /**
093         * Simply returns the <code>aggregate</code> argument without modification.  Can be overridden for custom behavior.
094         */
095        public AuthenticationInfo afterAllAttempts(AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException {
096            return aggregate;
097        }
098    }