# Interoperating with Java Lucene

## File Formats

`Zend_Search_Lucene` index file formats are binary compatible with Java Lucene version 1.4 and greater.

A detailed description of this format is available here: The currently supported Lucene index file format version is 2.3 (starting from Zend Framework 1.6)..

## Index Directory

After index creation, the index directory will contain several files:

- The `segments` file is a list of index segments.

- The `*.cfs` files contain index segments. Note! An optimized index always has only one segment.

- The `deletable` file is a list of files that are no longer used by the index, but which could not be deleted.

## Java Source Code

The Java program listing below provides an example of how to index a file using Java Lucene:

    /**
    * Index creation:
    */
    import org.apache.lucene.index.IndexWriter;
    import org.apache.lucene.document.*;

    import java.io.*

    ...

    IndexWriter indexWriter = new IndexWriter("/data/my_index",
                                              new SimpleAnalyzer(), true);

    ...

    String filename = "/path/to/file-to-index.txt"
    File f = new File(filename);

    Document doc = new Document();
    doc.add(Field.Text("path", filename));
    doc.add(Field.Keyword("modified",DateField.timeToString(f.lastModified())));
    doc.add(Field.Text("author", "unknown"));
    FileInputStream is = new FileInputStream(f);
    Reader reader = new BufferedReader(new InputStreamReader(is));
    doc.add(Field.Text("contents", reader));

    indexWriter.addDocument(doc);