[Backport 8.0] Complete implementation of Metrics type.

src/Elastic.Clients.Elasticsearch/Core/Infer/Metric/Metrics.cs

@@ -3,51 +3,87 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using Elastic.Transport;
 
 namespace Elastic.Clients.Elasticsearch;
 
+/// <summary>
+/// Represents a collection of unique metric names to be included in URL paths to limit the request.
+/// </summary>
 public sealed class Metrics : IEquatable<Metrics>, IUrlParameter
 {
-	// TODO: Complete this
+	private static readonly HashSet<string> EmptyMetrics = new();
 
-	//internal Metrics(IndicesStatsMetric metric) => Value = metric;
+	/// <summary>
+	/// An instance of <see cref="Metrics"/> representing all statistics.
+	/// </summary>
+	public static Metrics All { get; } = new("_all");
 
-	//internal Metrics(NodesStatsMetric metric) => Value = metric;
+	/// <summary>
+	///	Initializes a new instance of the <see cref="Metrics"/> class containing a single metric name.
+	/// </summary>
+	public Metrics(string metric)
+	{
+		if (string.IsNullOrEmpty(metric))
+			Values = EmptyMetrics;
 
-	//internal Metrics(NodesInfoMetric metric) => Value = metric;
+		Values = new HashSet<string>()
+		{
+			metric
+		};
+	}
 
-	//internal Metrics(ClusterStateMetric metric) => Value = metric;
+	/// <summary>
+	///	Initializes a new instance of the <see cref="Metrics"/> class containing a collection of metric names.
+	/// </summary>
+	public Metrics(IEnumerable<string> metrics)
+	{
+		if (metrics is null)
+			Values = EmptyMetrics;
 
-	//internal Metrics(WatcherStatsMetric metric) => Value = metric;
+		Values = new HashSet<string>(metrics);
+	}
 
-	//internal Metrics(NodesUsageMetric metric) => Value = metric;
+	private HashSet<string> Values { get; }
 
-	internal Enum Value { get; }
+	/// <inheritdoc />
+	public bool Equals(Metrics other)
+	{
+		if (other is null) return false;
 
-	public bool Equals(Metrics other) => Value.Equals(other.Value);
+		// Equality is true when the metrics names in both instances are equal, regardless of their order in the set.
+		return Values.OrderBy(t => t).SequenceEqual(other.Values.OrderBy(t => t));
+	}
 
-	string IUrlParameter.GetString(ITransportConfiguration settings) => string.Empty; // TODO Value.GetStringValue();
+	string IUrlParameter.GetString(ITransportConfiguration settings) => GetString();
 
-	//public static implicit operator Metrics(IndicesStatsMetric metric) => new Metrics(metric);
+	/// <inheritdoc />
+	public override string ToString() => GetString();
 
-	//public static implicit operator Metrics(NodesStatsMetric metric) => new Metrics(metric);
+	private string GetString()
+	{
+		if (Values == EmptyMetrics)
+			return string.Empty;
 
-	//public static implicit operator Metrics(NodesInfoMetric metric) => new Metrics(metric);
+		return string.Join(",", Values);
+	}
 
-	//public static implicit operator Metrics(ClusterStateMetric metric) => new Metrics(metric);
+	/// <inheritdoc />
+	public override int GetHashCode() => Values != null ? Values.GetHashCode() : 0;
 
-	//public static implicit operator Metrics(WatcherStatsMetric metric) => new Metrics(metric);
-
-	//public static implicit operator Metrics(NodesUsageMetric metric) => new Metrics(metric);
-
-	public bool Equals(Enum other) => Value.Equals(other);
-
-	public override bool Equals(object obj) => obj is Enum e ? Equals(e) : obj is Metrics m && Equals(m.Value);
+	public static bool operator ==(Metrics left, Metrics right) => Equals(left, right);
+	public static bool operator !=(Metrics left, Metrics right) => !Equals(left, right);
 
-	public override int GetHashCode() => Value != null ? Value.GetHashCode() : 0;
+	public static implicit operator Metrics(string metric) => new(metric);
+	public static implicit operator Metrics(string[] metrics) => new(metrics);
 
-	public static bool operator ==(Metrics left, Metrics right) => Equals(left, right);
+	/// <inheritdoc />
+	public override bool Equals(object obj)
+	{
+		if (obj is not Metrics metrics) return false;
 
-	public static bool operator !=(Metrics left, Metrics right) => !Equals(left, right);
+		return Equals(metrics);
+	}
 }

tests/Tests/Common/UrlParameters/Metrics/MetricsTests.cs

@@ -0,0 +1,67 @@
+// Licensed to Elasticsearch B.V under one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information.
+
+using Tests.Core.Extensions;
+
+using M = Elastic.Clients.Elasticsearch.Metrics;
+
+namespace Tests.Common.UrlParameters.Metrics;
+
+public class MetricsTests
+{
+	[U]
+	public void Equal()
+	{
+		var metrics = M.All;
+
+		M[] equal = { M.All };
+
+		foreach (var value in equal)
+		{
+			(value == metrics).ShouldBeTrue(value);
+			value.Should().Be(metrics);
+		}
+
+		metrics.Should().Be(M.All);
+	}
+
+	[U]
+	public void SequenceEqual()
+	{
+		M metricsOne = new[] { "completion", "merge" };
+		M metricsTwo = new[] { "merge", "completion" };
+
+		(metricsOne == metricsTwo).Should().BeTrue();
+		metricsOne.Should().Be(metricsTwo);
+	}
+
+	[U]
+	public void ToStringOverride()
+	{
+		M metrics = new[] { "completion", "merge" };
+		metrics.ToString().Should().Be("completion,merge");
+	}
+
+	[U]
+	public void NotEqual()
+	{
+		var metrics = M.All;
+
+		M[] notEqual = { "completion", "merge" };
+
+		foreach (var value in notEqual)
+		{
+			(value != metrics).ShouldBeTrue(value);
+			value.Should().NotBe(metrics);
+		}
+	}
+
+	[U]
+	public void Null()
+	{
+		var value = M.All;
+		(value == null).Should().BeFalse();
+		(null == value).Should().BeFalse();
+	}
+}