blob: f368e54fc0a23c339c34b8301ef0f687c88a742a (
plain) (
blame)
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
|
/*
* =========================================================================================
* Copyright © 2013-2014 the kamon project <http://kamon.io/>
*
* 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 kamon.util
/**
* This class implements an extremely efficient, thread-safe way to generate a
* incrementing sequence of Longs with a simple Long overflow protection.
*/
class Sequencer {
private val CloseToOverflow = Long.MaxValue - 1000000000
private val sequenceNumber = new PaddedAtomicLong(1L)
def next(): Long = {
val current = sequenceNumber.getAndIncrement
// check if this value is getting close to overflow?
if (current > CloseToOverflow) {
sequenceNumber.set(current - CloseToOverflow) // we need maintain the order
}
current
}
}
object Sequencer {
def apply(): Sequencer = new Sequencer()
}
|