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/* =========================================================================================
* Copyright © 2013-2017 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
/**
* Keeps track of the values produced by the source and produce the difference between the last two observed values
* when calling get. This class assumes the source increases monotonically and any produced value that violates this
* assumption will be dropped.
*
*/
class DifferentialSource(source: () => Long) {
private var previousValue = source()
def get(): Long = synchronized {
val currentValue = source()
val diff = currentValue - previousValue
previousValue = currentValue
if(diff < 0) 0 else diff
}
}
object DifferentialSource {
def apply(source: () => Long): DifferentialSource =
new DifferentialSource(source)
}
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