1 files changed, 60 insertions, 0 deletions
diff --git a/src/DotNetOpenId/Extensions/AliasManager.cs b/src/DotNetOpenId/Extensions/AliasManager.cs
index 52308d5..f4bbb04 100644
--- a/src/DotNetOpenId/Extensions/AliasManager.cs
+++ b/src/DotNetOpenId/Extensions/AliasManager.cs
@@ -37,6 +37,61 @@ namespace DotNetOpenId.Extensions {
 			aliasToTypeUriMap.Add(alias, typeUri);
 			typeUriToAliasMap.Add(typeUri, alias);
 		}
+		/// <summary>
+		/// Takes a sequence of type URIs and assigns aliases for all of them.
+		/// </summary>
+		/// <param name="typeUris">The type URIs to create aliases for.</param>
+		/// <param name="preferredTypeUriToAliases">An optional dictionary of URI/alias pairs that suggest preferred aliases to use if available for certain type URIs.</param>
+		public void AssignAliases(IEnumerable<string> typeUris, IDictionary<string, string> preferredTypeUriToAliases) {
+			// First go through the actually used type URIs and see which ones have matching preferred aliases.
+			if (preferredTypeUriToAliases != null) {
+				foreach (string typeUri in typeUris) {
+					if (typeUriToAliasMap.ContainsKey(typeUri)) {
+						// this Type URI is already mapped to an alias.
+						continue;
+					}
+
+					string preferredAlias;
+					if (preferredTypeUriToAliases.TryGetValue(typeUri, out preferredAlias) && !IsAliasUsed(preferredAlias)) {
+						SetAlias(preferredAlias, typeUri);
+					}
+				}
+			}
+
+			// Now go through the whole list again and assign whatever is left now that the preferred ones
+			// have gotten their picks where available.
+			foreach (string typeUri in typeUris) {
+				if (typeUriToAliasMap.ContainsKey(typeUri)) {
+					// this Type URI is already mapped to an alias.
+					continue;
+				}
+
+				assignNewAlias(typeUri);
+			}
+		}
+		/// <summary>
+		/// Sets up aliases for any Type URIs in a dictionary that do not yet have aliases defined,
+		/// and where the given preferred alias is still available.
+		/// </summary>
+		/// <param name="preferredTypeUriToAliases">A dictionary of type URI keys and alias values.</param>
+		public void SetPreferredAliasesWhereNotSet(IDictionary<string, string> preferredTypeUriToAliases) {
+			if (preferredTypeUriToAliases == null) throw new ArgumentNullException("preferredTypeUriToAliases");
+
+			foreach (var pair in preferredTypeUriToAliases) {
+				if (typeUriToAliasMap.ContainsKey(pair.Key)) {
+					// type URI is already mapped
+					continue;
+				}
+
+				if (aliasToTypeUriMap.ContainsKey(pair.Value)) {
+					// alias is already mapped
+					continue;
+				}
+
+				// The type URI and alias are as yet unset, so go ahead and assign them.
+				SetAlias(pair.Value, pair.Key);
+			}
+		}
 
 		/// <summary>
 		/// Gets the Type Uri encoded by a given alias.
@@ -57,6 +112,11 @@ namespace DotNetOpenId.Extensions {
 		public IEnumerable<string> Aliases {
 			get { return aliasToTypeUriMap.Keys; }
 		}
+		/// <summary>
+		/// Returns a value indicating whether an alias has already been assigned to a type URI.
+		/// </summary>
+		/// <param name="alias">The alias in question.</param>
+		/// <returns>True if the alias has already been assigned.  False otherwise.</returns>
 		public bool IsAliasUsed(string alias) {
 			if (string.IsNullOrEmpty(alias)) throw new ArgumentNullException("alias");
 			return aliasToTypeUriMap.ContainsKey(alias);