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// to you 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
//
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namespace Org.Apache.REEF.Common.Telemetry
{
    public interface IMetrics
    {
        /// <summary>
        /// Creates a system metric.
        /// </summary>
        /// <typeparam name="T">Type of the metric object.</typeparam>
        /// <param name="name">Name of the metric.</param>
        /// <param name="description">Description of the metric.</param>
        /// <param name="keepUpdateHistory">whether to keep a history of updates on this metric.</param>
        /// <returns></returns>
        T CreateAndRegisterMetric<T>(string name, string description, bool keepUpdateHistory)
            where T : MetricBase, new();

        /// <summary>
        /// Method that returns the collection of metric data.
        /// </summary>
        /// <returns></returns>
        IMetricSet GetMetricsData();

        /// <summary>
        /// Extracts the metric object if it has been registered.
        /// </summary>
        /// <param name="name">Name of the metric.</param>
        /// <param name="metric">The registered metric. null if not found.</param>
        /// <returns></returns>
        bool TryGetMetric<T>(string name, out T metric)
            where T : IMetric;
    }
}