It's necessary to create a custom analyzer when the built-in analyzers do not provide the needed behaviors for your search application. To continue with our CourtesyTitleFilter example, we will create CourtesyTitleAnalyzer.

The anatomy of an analyzer includes one tokenizer and one or more TokenFilters. We will build an Analyzer by extending from the Analyzer abstract class and implement the createComponents method.

public class CourtesyTitleAnalyzer extends Analyzer {

    @Override
    protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
    Tokenizer letterTokenizer = new LetterTokenizer(reader);
    TokenStream filter = new CourtesyTitleFilter(letterTokenizer);
    return new TokenStreamComponents(letterTokenizer, filter);
  }
}