/// <summary>
/// Creates a new instance initialized with the given stopword set
/// </summary>
/// <param name="version">
/// the Lucene version for cross version compatibility </param>
/// <param name="stopwords">
/// the analyzer's stopword set </param>
protected internal StopwordAnalyzerBase(Version version, CharArraySet stopwords)
{
matchVersion = version;
// analyzers should use char array set for stopwords!
this.stopwords = stopwords == null ? CharArraySet.EMPTY_SET : CharArraySet.unmodifiableSet(CharArraySet.Copy(version, stopwords));
}