docker-api/src/main/java/com/yahoo/vespa/hosted/dockerapi/metrics/GaugeWrapper.java


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// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.vespa.hosted.dockerapi.metrics;

import com.yahoo.metrics.simple.Gauge;

/**
 * Forwards sample to {@link com.yahoo.metrics.simple.Gauge} to be displayed in /state/v1/metrics,
 * while also saving the value so it can be accessed programatically later.
 *
 * @author valerijf
 */
public class GaugeWrapper implements MetricValue {
    private final Object lock = new Object();

    private final Gauge gauge;
    private double value;

    GaugeWrapper(Gauge gauge) {
        this.gauge = gauge;
    }

    public void sample(double x) {
        synchronized (lock) {
            gauge.sample(x);
            this.value = x;
        }
    }

    @Override
    public Number getValue() {
        synchronized (lock) {
            return value;
        }
    }
}