blob: 96a6ff3d0874bfceb1ca918650ea5113811a5db1 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
/*
* Copyright (C) 2009 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.util.concurrent;
import com.google.common.annotations.Beta;
import com.google.common.base.Throwables;
import java.util.concurrent.Executor;
/**
* Base class for services that do not need a thread while "running"
* but may need one during startup and shutdown. Subclasses can
* implement {@link #startUp} and {@link #shutDown} methods, each
* which run in a executor which by default uses a separate thread
* for each method.
*
* @author Chris Nokleberg
* @since 1.0
*/
@Beta
public abstract class AbstractIdleService implements Service {
/* use AbstractService for state management */
private final Service delegate = new AbstractService() {
@Override protected final void doStart() {
executor().execute(new Runnable() {
@Override public void run() {
try {
startUp();
notifyStarted();
} catch (Throwable t) {
notifyFailed(t);
throw Throwables.propagate(t);
}
}
});
}
@Override protected final void doStop() {
executor().execute(new Runnable() {
@Override public void run() {
try {
shutDown();
notifyStopped();
} catch (Throwable t) {
notifyFailed(t);
throw Throwables.propagate(t);
}
}
});
}
};
/** Constructor for use by subclasses. */
protected AbstractIdleService() {}
/** Start the service. */
protected abstract void startUp() throws Exception;
/** Stop the service. */
protected abstract void shutDown() throws Exception;
/**
* Returns the {@link Executor} that will be used to run this service.
* Subclasses may override this method to use a custom {@link Executor}, which
* may configure its worker thread with a specific name, thread group or
* priority. The returned executor's {@link Executor#execute(Runnable)
* execute()} method is called when this service is started and stopped,
* and should return promptly.
*/
protected Executor executor() {
final State state = state();
return new Executor() {
@Override
public void execute(Runnable command) {
MoreExecutors.newThread(serviceName() + " " + state, command).start();
}
};
}
@Override public String toString() {
return serviceName() + " [" + state() + "]";
}
// We override instead of using ForwardingService so that these can be final.
@Override public final ListenableFuture<State> start() {
return delegate.start();
}
@Override public final State startAndWait() {
return delegate.startAndWait();
}
@Override public final boolean isRunning() {
return delegate.isRunning();
}
@Override public final State state() {
return delegate.state();
}
@Override public final ListenableFuture<State> stop() {
return delegate.stop();
}
@Override public final State stopAndWait() {
return delegate.stopAndWait();
}
/**
* @since 13.0
*/
@Override public final void addListener(Listener listener, Executor executor) {
delegate.addListener(listener, executor);
}
/**
* @since 14.0
*/
@Override public final Throwable failureCause() {
return delegate.failureCause();
}
/**
* Returns the name of this service. {@link AbstractIdleService} may include the name in debugging
* output.
*
* @since 14.0
*/
protected String serviceName() {
return getClass().getSimpleName();
}
}
|
