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 */
019package org.apache.shiro.authc.pam;
020
021import org.apache.shiro.authc.AuthenticationException;
022import org.apache.shiro.authc.AuthenticationInfo;
023import org.apache.shiro.authc.AuthenticationToken;
024import org.apache.shiro.authc.MergableAuthenticationInfo;
025import org.apache.shiro.authc.SimpleAuthenticationInfo;
026import org.apache.shiro.realm.Realm;
027
028import java.util.Collection;
029
030
031/**
032 * Abstract base implementation for Shiro's concrete <code>AuthenticationStrategy</code>
033 * implementations.
034 *
035 * @since 0.9
036 */
037public abstract class AbstractAuthenticationStrategy implements AuthenticationStrategy {
038
039    /**
040     * Simply returns <code>new {@link org.apache.shiro.authc.SimpleAuthenticationInfo SimpleAuthenticationInfo}();</code>,
041     * which supports
042     * aggregating account data across realms.
043     */
044    public AuthenticationInfo beforeAllAttempts(Collection<? extends Realm> realms, AuthenticationToken token)
045            throws AuthenticationException {
046        return new SimpleAuthenticationInfo();
047    }
048
049    /**
050     * Simply returns the <code>aggregate</code> method argument, without modification.
051     */
052    public AuthenticationInfo beforeAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo aggregate)
053            throws AuthenticationException {
054        return aggregate;
055    }
056
057    /**
058     * Base implementation that will aggregate the specified <code>singleRealmInfo</code> into the
059     * <code>aggregateInfo</code> and then returns the aggregate.  Can be overridden by subclasses for custom behavior.
060     */
061    public AuthenticationInfo afterAttempt(Realm realm, AuthenticationToken token,
062                                           AuthenticationInfo singleRealmInfo, AuthenticationInfo aggregateInfo,
063                                           Throwable t) throws AuthenticationException {
064        AuthenticationInfo info;
065        if (singleRealmInfo == null) {
066            info = aggregateInfo;
067        } else {
068            if (aggregateInfo == null) {
069                info = singleRealmInfo;
070            } else {
071                info = merge(singleRealmInfo, aggregateInfo);
072            }
073        }
074
075        return info;
076    }
077
078    /**
079     * Merges the specified <code>info</code> argument into the <code>aggregate</code> argument and then returns an
080     * aggregate for continued use throughout the login process.
081     * <p/>
082     * This implementation merely checks to see if the specified <code>aggregate</code> argument is an instance of
083     * {@link org.apache.shiro.authc.MergableAuthenticationInfo MergableAuthenticationInfo}, and if so, calls
084     * <code>aggregate.merge(info)</code>  If it is <em>not</em> an instance of
085     * <code>MergableAuthenticationInfo</code>, an {@link IllegalArgumentException IllegalArgumentException} is thrown.
086     * Can be overridden by subclasses for custom merging behavior if implementing the
087     * {@link org.apache.shiro.authc.MergableAuthenticationInfo MergableAuthenticationInfo} is not desired for some reason.
088     */
089    protected AuthenticationInfo merge(AuthenticationInfo info, AuthenticationInfo aggregate) {
090        if (aggregate instanceof MergableAuthenticationInfo) {
091            ((MergableAuthenticationInfo) aggregate).merge(info);
092            return aggregate;
093        } else {
094            throw new IllegalArgumentException("Attempt to merge authentication info from multiple realms, but aggregate "
095                    + "AuthenticationInfo is not of type MergableAuthenticationInfo.");
096        }
097    }
098
099    /**
100     * Simply returns the <code>aggregate</code> argument without modification.  Can be overridden for custom behavior.
101     */
102    public AuthenticationInfo afterAllAttempts(AuthenticationToken token, AuthenticationInfo aggregate)
103            throws AuthenticationException {
104        return aggregate;
105    }
106}