1 files changed, 59 insertions, 0 deletions
diff --git a/crypto/src/util/collections/UnmodifiableSet.cs b/crypto/src/util/collections/UnmodifiableSet.cs
new file mode 100644
index 000000000..8792815ac
--- /dev/null
+++ b/crypto/src/util/collections/UnmodifiableSet.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Collections;
+
+namespace Org.BouncyCastle.Utilities.Collections
+{
+	public abstract class UnmodifiableSet
+		: ISet
+	{
+		protected UnmodifiableSet()
+		{
+		}
+
+		public virtual void Add(object o)
+		{
+			throw new NotSupportedException();
+		}
+
+		public virtual void AddAll(IEnumerable e)
+		{
+			throw new NotSupportedException();
+		}
+
+		public virtual void Clear()
+		{
+			throw new NotSupportedException();
+		}
+		
+		public abstract bool Contains(object o);
+
+		public abstract void CopyTo(Array array, int index);
+
+		public abstract int Count { get; }
+
+		public abstract IEnumerator GetEnumerator();
+
+		public abstract bool IsEmpty { get; }
+
+		public abstract bool IsFixedSize { get; }
+
+		public virtual bool IsReadOnly
+		{
+			get { return true; }
+		}
+
+		public abstract bool IsSynchronized { get; }
+
+		public abstract object SyncRoot { get; }
+
+		public virtual void Remove(object o)
+		{
+			throw new NotSupportedException();
+		}
+
+		public virtual void RemoveAll(IEnumerable e)
+		{
+			throw new NotSupportedException();
+		}
+	}
+}