Lifecycle


1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    * 
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   * 
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  
18  
19  package org.apache.catalina;
20  
21  
22  /**
23   * Common interface for component life cycle methods.  Catalina components
24   * may, but are not required to, implement this interface (as well as the
25   * appropriate interface(s) for the functionality they support) in order to
26   * provide a consistent mechanism to start and stop the component.
27   *
28   * @author Craig R. McClanahan
29   * @version $Revision: 467222 $ $Date: 2006-10-24 05:17:11 +0200 (mar., 24 oct. 2006) $
30   */
31  
32  public interface Lifecycle {
33  
34  
35      // ----------------------------------------------------- Manifest Constants
36  
37  
38      /**
39       * The LifecycleEvent type for the "component init" event.
40       */
41      public static final String   INIT_EVENT = "init";
42  
43  
44      /**
45       * The LifecycleEvent type for the "component start" event.
46       */
47      public static final String   START_EVENT = "start";
48  
49  
50      /**
51       * The LifecycleEvent type for the "component before start" event.
52       */
53      public static final String   BEFORE_START_EVENT = "before_start";
54  
55  
56      /**
57       * The LifecycleEvent type for the "component after start" event.
58       */
59      public static final String   AFTER_START_EVENT = "after_start";
60  
61  
62      /**
63       * The LifecycleEvent type for the "component stop" event.
64       */
65      public static final String   STOP_EVENT = "stop";
66  
67  
68      /**
69       * The LifecycleEvent type for the "component before stop" event.
70       */
71      public static final String   BEFORE_STOP_EVENT = "before_stop";
72  
73  
74      /**
75       * The LifecycleEvent type for the "component after stop" event.
76       */
77      public static final String   AFTER_STOP_EVENT = "after_stop";
78  
79  
80      /**
81       * The LifecycleEvent type for the "component destroy" event.
82       */
83      public static final String   DESTROY_EVENT = "destroy";
84  
85  
86      /**
87       * The LifecycleEvent type for the "periodic" event.
88       */
89      public static final String   PERIODIC_EVENT = "periodic";
90  
91  
92      // --------------------------------------------------------- Public Methods
93  
94  
95      /**
96       * Add a LifecycleEvent listener to this component.
97       *
98       * @param listener The listener to add
99       */
100     public void addLifecycleListener(LifecycleListener listener);
101 
102 
103     /**
104      * Get the lifecycle listeners associated with this lifecycle. If this 
105      * Lifecycle has no listeners registered, a zero-length array is returned.
106      */
107     public LifecycleListener[] findLifecycleListeners();
108 
109 
110     /**
111      * Remove a LifecycleEvent listener from this component.
112      *
113      * @param listener The listener to remove
114      */
115     public void removeLifecycleListener(LifecycleListener listener);
116 
117 
118     /**
119      * Prepare for the beginning of active use of the public methods of this
120      * component.  This method should be called before any of the public
121      * methods of this component are utilized.  It should also send a
122      * LifecycleEvent of type START_EVENT to any registered listeners.
123      *
124      * @exception LifecycleException if this component detects a fatal error
125      *  that prevents this component from being used
126      */
127     public void start() throws LifecycleException;
128 
129 
130     /**
131      * Gracefully terminate the active use of the public methods of this
132      * component.  This method should be the last one called on a given
133      * instance of this component.  It should also send a LifecycleEvent
134      * of type STOP_EVENT to any registered listeners.
135      *
136      * @exception LifecycleException if this component detects a fatal error
137      *  that needs to be reported
138      */
139     public void stop() throws LifecycleException;
140 
141 
142 }
143
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