io.engineblock.metrics.HdrDeltaHistogramAttachment Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of eb-api Show documentation

The driver API for engineblock; Provides the interfaces needed to build drivers that can be loaded by engineblock core

There is a newer version: 2.12.65

/*
 *
 *    Copyright 2016 jshook
 *    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 io.engineblock.metrics;

/**
 * Allow a DeltaHistogram to have attached metrics that also get a copy of
 * any input data.
 *
 * Terms
 * 
 *     Attaching metric - the original metric which maintains the attached metric.
 *     Attached metric - the "shadow" metric which receives the same input as the
 *     original metric.
 * 
 *
 * Implementing classes should reproduce their configuration, but not their content.
 * This means that attached metrics will receive content from the time they are attached,
 * and wil not see previous content. Attaching metrics are responsible for the creation
 * and ownership of the attached metrics.
 *
 * Implementations of the attaching metric should ensure that attached metrics
 * all receive the same data.
 *
 * The number of metrics that are allowed to be chained is implementation dependent.
 *
 * Implementations should ensure that any naming fields are marked differently so that
 * the attached metric does not have the exact same name as the attaching metric.
 */
public interface HdrDeltaHistogramAttachment extends HdrDeltaHistogramProvider {
    /**
     * Attach a metric.
     * @return the attached metric, after adding to the mirrors for the metric.
     */
    public HdrDeltaHistogramProvider attach();
}