Lucene Index

A specialized index implementation which connects to a Lucene directory.

Lucene is the de facto industry standard for full-text indexing in the Java ecosystem. If you want to learn more about Lucene, refer to the official documentation.

Lucene uses so-called documents which are basically key-value stores consisting of a name and a textual value. The Java entities are mapped to documents, which then can be searched.

Installation

Maven [pom.xml]

<dependency>
    <groupId>one.microstream</groupId>
    <artifactId>gigamap-lucene</artifactId>
    <version>1.1.0</version>
</dependency>

Example

First, we need to implement a DocumentPopulator, which maps the Java entities into documents.

The DocumentPopulator comes with several create*Field methods that allow us to create document entries quickly.

class PersonDocumentPopulator extends DocumentPopulator<Person>
{
    @Override
    public void populate(Document document, Person person)
    {
        document.add(createTextField("firstName", person.getFirstName()));
        document.add(createTextField("lastName" , person.getLastName ()));
    }
}

Then we create a LuceneContext and register it at the GigaMap.

LuceneContext<Person> luceneContext = LuceneContext.New(
    Paths.get("lucene-store"),    // path to directory
    new PersonDocumentPopulator() // our document populator
);

LuceneIndex<Person> luceneIndex = gigaMap.index().register(LuceneIndex.Category(luceneContext));

Afterward we are able to query the index using the Lucene query language.

List<Person> result = luceneIndex.query("firstName:John");