1 // ========================================================================
2 // Copyright 2004-2005 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 // http://www.apache.org/licenses/LICENSE-2.0
8 // Unless required by applicable law or agreed to in writing, software
9 // distributed under the License is distributed on an "AS IS" BASIS,
10 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11 // See the License for the specific language governing permissions and
12 // limitations under the License.
13 // ========================================================================
14
15 package org.mortbay.component;
16
17 import java.util.EventListener;
18
19 import org.mortbay.util.LazyList;
20
21 /* ------------------------------------------------------------ */
22 /**
23 * The lifecycle interface for generic components.
24 * <br />
25 * Classes implementing this interface have a defined life cycle
26 * defined by the methods of this interface.
27 *
28 * @author Greg Wilkins (gregw)
29 */
30 public interface LifeCycle
31 {
32 /* ------------------------------------------------------------ */
33 /**
34 * Starts the component.
35 * @throws Exception If the component fails to start
36 * @see #isStarted()
37 * @see #stop()
38 * @see #isFailed()
39 */
40 public void start()
41 throws Exception;
42
43 /* ------------------------------------------------------------ */
44 /**
45 * Stops the component.
46 * The component may wait for current activities to complete
47 * normally, but it can be interrupted.
48 * @exception Exception If the component fails to stop
49 * @see #isStopped()
50 * @see #start()
51 * @see #isFailed()
52 */
53 public void stop()
54 throws Exception;
55
56 /* ------------------------------------------------------------ */
57 /**
58 * @return true if the component is starting or has been started.
59 */
60 public boolean isRunning();
61
62 /* ------------------------------------------------------------ */
63 /**
64 * @return true if the component has been started.
65 * @see #start()
66 * @see #isStarting()
67 */
68 public boolean isStarted();
69
70 /* ------------------------------------------------------------ */
71 /**
72 * @return true if the component is starting.
73 * @see #isStarted()
74 */
75 public boolean isStarting();
76
77 /* ------------------------------------------------------------ */
78 /**
79 * @return true if the component is stopping.
80 * @see #isStopped()
81 */
82 public boolean isStopping();
83
84 /* ------------------------------------------------------------ */
85 /**
86 * @return true if the component has been stopped.
87 * @see #stop()
88 * @see #isStopping()
89 */
90 public boolean isStopped();
91
92 /* ------------------------------------------------------------ */
93 /**
94 * @return true if the component has failed to start or has failed to stop.
95 */
96 public boolean isFailed();
97
98 /* ------------------------------------------------------------ */
99 public void addLifeCycleListener(LifeCycle.Listener listener);
100
101 /* ------------------------------------------------------------ */
102 public void removeLifeCycleListener(LifeCycle.Listener listener);
103
104
105 /* ------------------------------------------------------------ */
106 /** Listener.
107 * A listener for Lifecycle events.
108 */
109 public interface Listener extends EventListener
110 {
111 public void lifeCycleStarting(LifeCycle event);
112 public void lifeCycleStarted(LifeCycle event);
113 public void lifeCycleFailure(LifeCycle event,Throwable cause);
114 public void lifeCycleStopping(LifeCycle event);
115 public void lifeCycleStopped(LifeCycle event);
116 }
117 }