blob: 2dc4c0e272df58638b475fe9b9cface122d0a010 (
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
|
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.qpid.junit.extensions;
/**
* SleepThrottle is a Throttle implementation that generates short pauses using the thread sleep methods. As the pauses
* get shorter, this technique gets more innacurate. In practice, around 100 Hz is the cap rate for accuracy.
*
* <p/><table id="crc"><caption>CRC Card</caption>
* <tr><th> Responsibilities <th> Collaborations
* <tr><td> Accept throttling rate in operations per second.
* <tr><td> Inject short pauses to fill out processing cycles to a specified rate.
* <tr><td> Check against a throttle speed without waiting.
* </table>
*
* @author Rupert Smith
*/
public class SleepThrottle extends BaseThrottle implements Throttle
{
/** Holds the time of the last call to the throttle method in nano seconds. */
private long lastTimeNanos;
/**
* This method can only be called at the rate set by the {@link #setRate} method, if it is called faster than this
* it will inject short pauses to restrict the call rate to that rate.
*/
public void throttle()
{
// Get the current time in nanos.
long currentTimeNanos = System.nanoTime();
// Don't introduce any pause on the first call.
if (!firstCall)
{
// Check if there is any time left in the cycle since the last call to this method and introduce a short pause
// to fill that time if there is.
long remainingTimeNanos = cycleTimeNanos - (currentTimeNanos - lastTimeNanos);
if (remainingTimeNanos > 0)
{
long milliPause = remainingTimeNanos / 1000000;
int nanoPause = (int) (remainingTimeNanos % 1000000);
try
{
Thread.sleep(milliPause, nanoPause);
}
catch (InterruptedException e)
{
// Restore the interrupted thread, in-case the caller is checking for it.
Thread.currentThread().interrupt();
}
}
}
else
{
firstCall = false;
}
// Update the last time stamp.
lastTimeNanos = System.nanoTime();
}
}
|
