Book Image

Lucene 4 Cookbook

By : Edwood Ng, Vineeth Mohan
Book Image

Lucene 4 Cookbook

By: Edwood Ng, Vineeth Mohan

Overview of this book

Table of Contents (16 chapters)
Lucene 4 Cookbook
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Defining custom analyzers


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.

How to do it…

Here is the sample code for CourtesyTitleAnalyzer:

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);
  }
}

How it works…

An Analyzer is created by extending from the Analyzer abstract class as shown in this example. Then we override the createComponents...