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Gauge.java
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Gauge.java
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/*
**********************************************************************
* Copyright (c) 2017, 2022 Contributors to the Eclipse Foundation
* 2010-2013 Coda Hale, Yammer.com
*
* See the NOTICES file(s) distributed with this work for additional
* information regarding copyright ownership.
*
* 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.
*
* SPDX-License-Identifier: Apache-2.0
**********************************************************************/
package org.eclipse.microprofile.metrics;
/**
* A gauge metric is an instantaneous reading of a particular value. To instrument a queue's depth, for example:<br>
*
* <pre>
* <code>
* final Queue<String> queue = new ConcurrentLinkedQueue<String>();
* final Gauge<Integer> queueDepth = new Gauge<Integer>() {
* public Integer getValue() {
* return queue.size();
* }
* };
* </code>
* </pre>
*
* @param <T>
* the type of the metric's value. Must be numeric.
*/
@FunctionalInterface
public interface Gauge<T extends Number> extends Metric {
/**
* Returns the metric's current value.
*
* @return the metric's current value
*/
T getValue();
}