com.hazelcast.internal.metrics.Metric Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.internal.metrics;
/**
* A Metric is a 'quantitative measure' of something for example the number of
* operations pending, number of operations per second being executed etc.
*
* Each metric is uniquely identified using a name. See {@link #getName()}.
*
* A metric gets its content from a probe. An probe can be one of the following:
*
* - a method with the {@link Probe} annotation
* - a field with the {@link Probe} annotation
* - a {@link LongProbeFunction}
* - a {@link DoubleProbeFunction}
*
*
* If the Metric is obtained before a probe is registered, the Metric is without
* probe. As long as no probe is available, every time the metrics needs a value,
* it will look up the probe in the {@link MetricsRegistry}.
*/
public interface Metric {
/**
* Gets the name that identifies this metric.
*
* The returned value will never change and never be null.
*
* @return the name of the metric.
*/
String getName();
}