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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.shiro.authc.pam;
20  
21  import org.apache.shiro.authc.AuthenticationException;
22  import org.apache.shiro.authc.AuthenticationInfo;
23  import org.apache.shiro.authc.AuthenticationToken;
24  import org.apache.shiro.realm.Realm;
25  import org.apache.shiro.subject.PrincipalCollection;
26  
27  import java.util.Collection;
28  
29  /**
30   * {@link AuthenticationStrategy} implementation that only accepts the account data from
31   * the first successfully consulted Realm and ignores all subsequent realms.  This is slightly
32   * different behavior than {@link AtLeastOneSuccessfulStrategy}, so please review both to see
33   * which one meets your needs better.
34   *
35   * @see AtLeastOneSuccessfulStrategy AtLeastOneSuccessfulAuthenticationStrategy
36   * @since 0.9
37   */
38  public class FirstSuccessfulStrategy extends AbstractAuthenticationStrategy {
39  
40      private boolean stopAfterFirstSuccess;
41  
42      public void setStopAfterFirstSuccess (boolean stopAfterFirstSuccess ) {
43  
44          this.stopAfterFirstSuccess  = stopAfterFirstSuccess ;
45      }
46  
47      public boolean getStopAfterFirstSuccess() {
48          return stopAfterFirstSuccess ;
49      }
50  
51      /**
52       * Returns {@code null} immediately, relying on this class's {@link #merge merge} implementation to return
53       * only the first {@code info} object it encounters, ignoring all subsequent ones.
54       */
55      public AuthenticationInfo beforeAllAttempts(Collection<? extends Realm> realms, AuthenticationToken token) throws AuthenticationException {
56          return null;
57      }
58  
59  
60      /**
61       * Throws ShortCircuitIterationException if stopAfterFirstSuccess is set and authentication is 
62       * successful with a previously consulted realm. 
63       * Returns the <code>aggregate</code> method argument, without modification
64       * otherwise.
65       */
66      public AuthenticationInfo.html#AuthenticationInfo">AuthenticationInfo beforeAttempt(Realm realm, AuthenticationToken token, AuthenticationInfo aggregate) throws AuthenticationException {
67          if (getStopAfterFirstSuccess() && aggregate != null && !isEmpty(aggregate.getPrincipals())) {
68              throw new ShortCircuitIterationException();
69          }
70          return aggregate;
71      }
72  
73      
74  
75      private static boolean isEmpty(PrincipalCollection pc) {
76          return pc == null || pc.isEmpty();
77      }
78  
79      /**
80       * Returns the specified {@code aggregate} instance if is non null and valid (that is, has principals and they are
81       * not empty) immediately, or, if it is null or not valid, the {@code info} argument is returned instead.
82       * <p/>
83       * This logic ensures that the first valid info encountered is the one retained and all subsequent ones are ignored,
84       * since this strategy mandates that only the info from the first successfully authenticated realm be used.
85       */
86      protected AuthenticationInfo/../../org/apache/shiro/authc/AuthenticationInfo.html#AuthenticationInfo">AuthenticationInfo/../../org/apache/shiro/authc/AuthenticationInfo.html#AuthenticationInfo">AuthenticationInfo merge(AuthenticationInfo/../../org/apache/shiro/authc/AuthenticationInfo.html#AuthenticationInfo">AuthenticationInfo info, AuthenticationInfo aggregate) {
87          if (aggregate != null && !isEmpty(aggregate.getPrincipals())) {
88              return aggregate;
89          }
90          return info != null ? info : aggregate;
91      }
92  }