1 // ========================================================================
2 // Copyright (c) 2004-2009 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13
14 package org.eclipse.jetty.util.component;
15
16 import java.util.EventListener;
17
18 /* ------------------------------------------------------------ */
19 /**
20 * The lifecycle interface for generic components.
21 * <br />
22 * Classes implementing this interface have a defined life cycle
23 * defined by the methods of this interface.
24 *
25 *
26 */
27 public interface LifeCycle
28 {
29 /* ------------------------------------------------------------ */
30 /**
31 * Starts the component.
32 * @throws Exception If the component fails to start
33 * @see #isStarted()
34 * @see #stop()
35 * @see #isFailed()
36 */
37 public void start()
38 throws Exception;
39
40 /* ------------------------------------------------------------ */
41 /**
42 * Stops the component.
43 * The component may wait for current activities to complete
44 * normally, but it can be interrupted.
45 * @exception Exception If the component fails to stop
46 * @see #isStopped()
47 * @see #start()
48 * @see #isFailed()
49 */
50 public void stop()
51 throws Exception;
52
53 /* ------------------------------------------------------------ */
54 /**
55 * @return true if the component is starting or has been started.
56 */
57 public boolean isRunning();
58
59 /* ------------------------------------------------------------ */
60 /**
61 * @return true if the component has been started.
62 * @see #start()
63 * @see #isStarting()
64 */
65 public boolean isStarted();
66
67 /* ------------------------------------------------------------ */
68 /**
69 * @return true if the component is starting.
70 * @see #isStarted()
71 */
72 public boolean isStarting();
73
74 /* ------------------------------------------------------------ */
75 /**
76 * @return true if the component is stopping.
77 * @see #isStopped()
78 */
79 public boolean isStopping();
80
81 /* ------------------------------------------------------------ */
82 /**
83 * @return true if the component has been stopped.
84 * @see #stop()
85 * @see #isStopping()
86 */
87 public boolean isStopped();
88
89 /* ------------------------------------------------------------ */
90 /**
91 * @return true if the component has failed to start or has failed to stop.
92 */
93 public boolean isFailed();
94
95 /* ------------------------------------------------------------ */
96 public void addLifeCycleListener(LifeCycle.Listener listener);
97
98 /* ------------------------------------------------------------ */
99 public void removeLifeCycleListener(LifeCycle.Listener listener);
100
101
102 /* ------------------------------------------------------------ */
103 /** Listener.
104 * A listener for Lifecycle events.
105 */
106 public interface Listener extends EventListener
107 {
108 public void lifeCycleStarting(LifeCycle event);
109 public void lifeCycleStarted(LifeCycle event);
110 public void lifeCycleFailure(LifeCycle event,Throwable cause);
111 public void lifeCycleStopping(LifeCycle event);
112 public void lifeCycleStopped(LifeCycle event);
113 }
114 }