Lucene Configuration

The LuceneContext provides configuration options for the Lucene index.

LuceneContext Factory Methods

// Embedded storage (persisted with GigaMap)
LuceneContext<E> context = LuceneContext.New(documentPopulator);

// File system storage (MMapDirectory)
LuceneContext<E> context = LuceneContext.New(directoryPath, documentPopulator);

// Custom directory creator
LuceneContext<E> context = LuceneContext.New(directoryCreator, documentPopulator);

// Full customization
LuceneContext<E> context = LuceneContext.New(directoryCreator, analyzerCreator, documentPopulator);

// Full customization including the commit behavior
LuceneContext<E> context = LuceneContext.New(directoryCreator, analyzerCreator, documentPopulator, autoCommit);

Directory Creators

The DirectoryCreator controls where index data is stored.

Creator Description Use Case

Creator	Description	Use Case
Embedded (default)	Stores data inside the GigaMap object graph	When you want the index persisted with your data
`DirectoryCreator.MMap(path)`	Memory-mapped file storage	Production environments, large indexes
`DirectoryCreator.ByteBuffers()`	In-memory storage	Testing, temporary indexes

Embedded (default)

Stores data inside the GigaMap object graph

When you want the index persisted with your data

DirectoryCreator.MMap(path)

Memory-mapped file storage

Production environments, large indexes

DirectoryCreator.ByteBuffers()

In-memory storage

Testing, temporary indexes

Embedded Storage

When no directory creator is specified, the index data is stored inside the GigaMap’s object graph. This means the index is automatically persisted when the GigaMap is stored with EclipseStore.

LuceneContext<Article> context = LuceneContext.New(
    new ArticleDocumentPopulator()
);

MMap Directory

For large indexes or when you want separate storage, use memory-mapped file storage.

LuceneContext<Article> context = LuceneContext.New(
    Paths.get("/data/lucene-index"),
    new ArticleDocumentPopulator()
);

// Or explicitly
LuceneContext<Article> context = LuceneContext.New(
    DirectoryCreator.MMap(Paths.get("/data/lucene-index")),
    new ArticleDocumentPopulator()
);

ByteBuffers Directory

For testing or temporary in-memory indexes.

LuceneContext<Article> context = LuceneContext.New(
    DirectoryCreator.ByteBuffers(),
    new ArticleDocumentPopulator()
);

Analyzer Creators

The AnalyzerCreator controls how text is tokenized and processed.

Standard Analyzer (Default)

The default analyzer tokenizes on word boundaries, removes common stopwords, and lowercases text.

// Uses StandardAnalyzer by default
LuceneContext<Article> context = LuceneContext.New(
    new ArticleDocumentPopulator()
);

// Or explicitly
LuceneContext<Article> context = LuceneContext.New(
    DirectoryCreator.ByteBuffers(),
    AnalyzerCreator.Standard(),
    new ArticleDocumentPopulator()
);

Custom Analyzer

For language-specific or domain-specific text processing, subclass AnalyzerCreator and override createAnalyzer().

StandardAnalyzer ships with lucene-core. Language-specific analyzers such as GermanAnalyzer live in lucene-analysis-common, which has to be added as an additional dependency.

public class GermanAnalyzerCreator extends AnalyzerCreator
{
    @Override
    public Analyzer createAnalyzer()
    {
        return new GermanAnalyzer();
    }
}

LuceneContext<Article> context = LuceneContext.New(
    DirectoryCreator.MMap(indexPath),
    new GermanAnalyzerCreator(),
    new ArticleDocumentPopulator()
);

Auto-Commit

By default, changes are automatically committed after each operation. For bulk operations, you may want to disable auto-commit for better performance. Pass the flag to the four-argument LuceneContext.New(…) factory.

With autoCommit disabled, pending changes are still committed automatically at every GigaMap.store() boundary, so an explicit LuceneIndex.commit() is only needed to commit between stores.

// Manual commit for bulk operations; null directory creator means embedded storage
LuceneContext<Article> context = LuceneContext.New(
    null                             ,
    AnalyzerCreator.Standard()       ,
    new ArticleDocumentPopulator()   ,
    false                              // autoCommit
);

GigaMap<Article> articles = GigaMap.New();
LuceneIndex<Article> luceneIndex = articles.index().register(LuceneIndex.Category(context));

// Add many entities
for (Article article : bulkArticles)
{
    articles.add(article);
}

// Commit once at the end
luceneIndex.commit();

Thread Safety

All Lucene index operations are synchronized on the parent GigaMap, making the index safe for concurrent access from multiple threads.

Resource Management

The Lucene index implements Closeable. Call close() to release resources.

luceneIndex.close();

After closing, the index can be re-initialized on the next query.