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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.mgt;
20  
21  import org.apache.shiro.cache.CacheManager;
22  import org.apache.shiro.cache.CacheManagerAware;
23  import org.apache.shiro.event.EventBus;
24  import org.apache.shiro.event.EventBusAware;
25  import org.apache.shiro.event.support.DefaultEventBus;
26  import org.apache.shiro.util.Destroyable;
27  import org.apache.shiro.util.LifecycleUtils;
28  
29  
30  /**
31   * A very basic starting point for the SecurityManager interface that merely provides logging and caching
32   * support.  All actual {@code SecurityManager} method implementations are left to subclasses.
33   * <p/>
34   * <b>Change in 1.0</b> - a default {@code CacheManager} instance is <em>not</em> created by default during
35   * instantiation.  As caching strategies can vary greatly depending on an application's needs, a {@code CacheManager}
36   * instance must be explicitly configured if caching across the framework is to be enabled.
37   *
38   * @since 0.9
39   */
40  public abstract class CachingSecurityManager implements SecurityManager, Destroyable, CacheManagerAware, EventBusAware {
41  
42      /**
43       * The CacheManager to use to perform caching operations to enhance performance.  Can be null.
44       */
45      private CacheManager cacheManager;
46  
47      /**
48       * The EventBus to use to use to publish and receive events of interest during Shiro's lifecycle.
49       * @since 1.3
50       */
51      private EventBus eventBus;
52  
53      /**
54       * Default no-arg constructor that will automatically attempt to initialize a default cacheManager
55       */
56      public CachingSecurityManager() {
57          //use a default event bus:
58          setEventBus(new DefaultEventBus());
59      }
60  
61      /**
62       * Returns the CacheManager used by this SecurityManager.
63       *
64       * @return the cacheManager used by this SecurityManager
65       */
66      public CacheManager getCacheManager() {
67          return cacheManager;
68      }
69  
70      /**
71       * Sets the CacheManager used by this {@code SecurityManager} and potentially any of its
72       * children components.
73       * <p/>
74       * After the cacheManager attribute has been set, the template method
75       * {@link #afterCacheManagerSet afterCacheManagerSet()} is executed to allow subclasses to adjust when a
76       * cacheManager is available.
77       *
78       * @param cacheManager the CacheManager used by this {@code SecurityManager} and potentially any of its
79       *                     children components.
80       */
81      public void setCacheManager(CacheManager cacheManager) {
82          this.cacheManager = cacheManager;
83          afterCacheManagerSet();
84      }
85  
86      /**
87       * Template callback to notify subclasses that a
88       * {@link org.apache.shiro.cache.CacheManager CacheManager} has been set and is available for use via the
89       * {@link #getCacheManager getCacheManager()} method.
90       */
91      protected void afterCacheManagerSet() {
92          applyEventBusToCacheManager();
93      }
94  
95      /**
96       * Returns the {@code EventBus} used by this SecurityManager and potentially any of its children components.
97       *
98       * @return the {@code EventBus} used by this SecurityManager and potentially any of its children components.
99       * @since 1.3
100      */
101     public EventBus getEventBus() {
102         return eventBus;
103     }
104 
105     /**
106      * Sets the EventBus used by this {@code SecurityManager} and potentially any of its
107      * children components.
108      * <p/>
109      * After the eventBus attribute has been set, the template method
110      * {@link #afterEventBusSet() afterEventBusSet()} is executed to allow subclasses to adjust when a
111      * eventBus is available.
112      *
113      * @param eventBus the EventBus used by this {@code SecurityManager} and potentially any of its
114      *                     children components.
115      * @since 1.3
116      */
117     public void setEventBus(EventBus eventBus) {
118         this.eventBus = eventBus;
119         afterEventBusSet();
120     }
121 
122     /**
123      * @since 1.3
124      */
125     protected void applyEventBusToCacheManager() {
126         if (this.eventBus != null && this.cacheManager != null && this.cacheManager instanceof EventBusAware) {
127             ((EventBusAware)this.cacheManager).setEventBus(this.eventBus);
128         }
129     }
130 
131     /**
132      * Template callback to notify subclasses that an {@link EventBus EventBus} has been set and is available for use
133      * via the {@link #getEventBus() getEventBus()} method.
134      *
135      * @since 1.3
136      */
137     protected void afterEventBusSet() {
138         applyEventBusToCacheManager();
139     }
140 
141     /**
142      * Destroys the {@link #getCacheManager() cacheManager} via {@link LifecycleUtils#destroy LifecycleUtils.destroy}.
143      */
144     public void destroy() {
145         LifecycleUtils.destroy(getCacheManager());
146         this.cacheManager = null;
147         LifecycleUtils.destroy(getEventBus());
148         this.eventBus = new DefaultEventBus();
149     }
150 
151 }