/// <summary>
/// Returns a read-only view of the <see cref="Int32HashSet"/>.</summary>
/// <returns>
/// A read-only wrapper around the <see cref="Int32HashSet"/>.</returns>
/// <remarks><para>
/// Attempting to modify the read-only wrapper returned by <b>AsReadOnly</b> will raise a
/// <see cref="NotSupportedException"/>. Note that the original collection may still change,
/// and any such changes will be reflected in the read-only view.
/// </para><para>
/// <b>AsReadOnly</b> buffers the newly created read-only wrapper when the method is first
/// called, and returns the buffered value on subsequent calls.</para></remarks>
public Int32HashSet AsReadOnly()
{
if (ReadOnlyWrapper == null)
{
ReadOnlyWrapper = new Int32HashSet(this, true);
}
return(ReadOnlyWrapper);
}
/// <summary>
/// Initializes a new instance of the <see cref="Int32HashSet"/> class that is a read-only
/// view of the specified instance.</summary>
/// <param name="collection">
/// The <see cref="Int32HashSet"/> collection that is wrapped by the new instance.</param>
/// <param name="readOnly">
/// The initial value for the <see cref="IsReadOnly"/> property. This argument must be
/// <c>true</c>.</param>
/// <exception cref="ArgumentNullException">
/// <paramref name="collection"/> is a null reference.</exception>
/// <exception cref="InvalidOperationException">
/// <paramref name="readOnly"/> is <c>false</c>.</exception>
/// <remarks>
/// This constructor is used to create a read-only wrapper around an existing collection.
/// The new instance shares the data of the specified <paramref name="collection"/>.
/// </remarks>
protected Int32HashSet(Int32HashSet collection, bool readOnly)
{
if (collection == null)
{
ThrowHelper.ThrowArgumentNullException("collection");
}
if (!readOnly)
{
ThrowHelper.ThrowArgumentExceptionWithFormat(
"readOnly", Strings.ArgumentEquals, false);
}
_data = collection._data;
ReadOnlyFlag = readOnly;
ReadOnlyWrapper = this;
}