/Utilities/Collections/UniqueHashtable.cs

using System;

using System.Collections;

using NUnit.Framework;



namespace Delta.Utilities.Collections

{

	/// <summary>

	/// Exactly the same as the Hashtable, but adds only new key/value pairs

	/// if the key does not currently exists (the key is unique). This class

	/// also enforces KeyType and ValueType unlike Hashtable, which accepts

	/// all kind of objects.

	/// </summary>

	[Serializable]

	public class UniqueHashtable<TKeyType, TValueType> : Hashtable

	{

		#region Add (Public)

		/// <summary>

		/// Add new key/value pair, will not add if the key does already exists!

		/// </summary>

		/// <param name="key">Key</param>

		/// <param name="val">val</param>

		public void Add(TKeyType key, TValueType val)

		{

			if (!Contains(key))

			{

				base.Add(key, val);

			}

		}

		#endregion



		#region WriteKeys (Public)

		/// <summary>

		/// Write all keys into a string for output/debug/tracing/etc.

		/// </summary>

		/// <returns>Output string with all the values.</returns>

		public string WriteKeys()

		{

			string ret = "";

			foreach (object obj in Keys)

			{

				ret +=

					ret.Length == 0

						? ""

						: ", " + obj;

			}

			return ret;

		}

		#endregion

	}



	/// <summary>

	/// Test unique hashtable

	/// </summary>

	internal class TestUniqueHashtableHelper

	{

		#region TestAddingData (Public)

		/// <summary>

		/// Test adding data

		/// </summary>

		[Test]

		public void TestAddingData()

		{

			UniqueHashtable<int, int> testTable = new UniqueHashtable<int, int>();

			// Add value 1 at key 1

			testTable.Add(1, 1);

			// Try to add another value 2 at key 1 (should be ignored)

			testTable.Add(1, 2);

			// And add another value 1 at key 2.

			testTable.Add(2, 1);

			// All values should be 1 now!

			foreach (int num in testTable.Values)

			{

				Assert.Equal(1, num);

			}

		}

		#endregion

	}

}