Version 3.0.381

SharedBusinessLogic/Model/Map/IMapSpan.cs

@@ -0,0 +1,14 @@
+namespace ShareeBike.Model.Map
+{
+	public interface IMapSpan
+	{
+		/// <summary> Center of map displayed area.</summary>
+		IPosition Center { get; }
+
+		/// <summary> Radius of displayed map area. </summary>
+		double Radius { get; }
+
+		/// <summary> Gets if map span is valid or not. </summary>
+		bool IsValid { get; }
+	}
+}

SharedBusinessLogic/Model/Map/MapSpan.cs

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+using System;
+
+namespace ShareeBike.Model.Map
+{
+	/// <summary> Holds the displayed map area. </summary>
+	public class MapSpan : IMapSpan
+	{
+		internal MapSpan(IPosition center, double radius)
+		{
+			if (!GetIsValid(center, radius))
+				throw new ArgumentNullException();
+
+			Center = center;
+			Radius = radius;
+		}
+
+		/// <summary> Center of map displayed area.</summary>
+		public IPosition Center { get; }
+
+		/// <summary> Radius of displayed map area. </summary>
+		public double Radius { get; }
+
+		public bool IsValid => GetIsValid(Center, Radius);
+
+		public static bool GetIsValid(IPosition center, double radius)
+			=> center != null
+				&& center.IsValid
+				&& !double.IsNaN(radius);
+	}
+}

SharedBusinessLogic/Model/Map/MapSpanFactory.cs

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+
+namespace ShareeBike.Model.Map
+{
+	public static class MapSpanFactory
+	{
+		public static IMapSpan Create(IPosition position = null, double radius = double.NaN)
+			=> MapSpan.GetIsValid(position, radius)
+				? new MapSpan(position, radius) as IMapSpan
+				: new NullMapSpan();
+	}
+}

SharedBusinessLogic/Model/Map/NullMapSpan.cs

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+
+namespace ShareeBike.Model.Map
+{
+	public class NullMapSpan : IMapSpan
+	{
+		internal NullMapSpan() { }
+
+		/// <summary> Center of map displayed area.</summary>
+		public IPosition Center { get; } = PositionFactory.Create();
+
+		/// <summary> Radius of displayed map area. </summary>
+		public double Radius => double.NaN;
+
+		public bool IsValid => MapSpan.GetIsValid(Center, Radius);
+	}
+}