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Diffstat (limited to 'kamon-core/src/main/scala/kamon/util/Sequencer.scala')
-rw-r--r-- | kamon-core/src/main/scala/kamon/util/Sequencer.scala | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/util/Sequencer.scala b/kamon-core/src/main/scala/kamon/util/Sequencer.scala new file mode 100644 index 00000000..8901ba81 --- /dev/null +++ b/kamon-core/src/main/scala/kamon/util/Sequencer.scala @@ -0,0 +1,40 @@ +/* + * ========================================================================================= + * 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 + * simple 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() +}
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