package com.fox.facet;

import java.io.File;

import java.io.IOException;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import org.apache.lucene.analysis.Analyzer;

import org.apache.lucene.analysis.standard.StandardAnalyzer;

import org.apache.lucene.document.Document;

import org.apache.lucene.document.Field.Store;

import org.apache.lucene.document.StringField;

import org.apache.lucene.facet.index.CategoryDocumentBuilder;

import org.apache.lucene.facet.search.FacetsCollector;

import org.apache.lucene.facet.search.params.CountFacetRequest;

import org.apache.lucene.facet.search.params.FacetSearchParams;

import org.apache.lucene.facet.search.results.FacetResult;

import org.apache.lucene.facet.search.results.FacetResultNode;

import org.apache.lucene.facet.taxonomy.CategoryPath;

import org.apache.lucene.facet.taxonomy.TaxonomyReader;

import org.apache.lucene.facet.taxonomy.TaxonomyWriter;

import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyReader;

import org.apache.lucene.facet.taxonomy.directory.DirectoryTaxonomyWriter;

import org.apache.lucene.index.DirectoryReader;

import org.apache.lucene.index.IndexReader;

import org.apache.lucene.index.IndexWriter;

import org.apache.lucene.index.IndexWriterConfig;

import org.apache.lucene.index.IndexWriterConfig.OpenMode;

import org.apache.lucene.index.Term;

import org.apache.lucene.search.IndexSearcher;

import org.apache.lucene.search.MultiCollector;

import org.apache.lucene.search.Query;

import org.apache.lucene.search.TermQuery;

import org.apache.lucene.search.TopScoreDocCollector;

import org.apache.lucene.store.Directory;

import org.apache.lucene.store.FSDirectory;

import org.apache.lucene.util.Version;

public class FacetingExample {

    private static final String INDEX = "d:/facet/index";

    private static final String INDEX_TAXO = "d:/facet/taxo";

    public static void main(final String[] args) throws IOException {

        Directory dir = FSDirectory.open(new File(INDEX));

        Directory taxoDir = FSDirectory.open(new File(INDEX_TAXO));

        Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_40);

        IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_40, analyzer);

        iwc.setOpenMode(OpenMode.CREATE);

        IndexWriter writer = new IndexWriter(dir, iwc);

        TaxonomyWriter taxoWriter = new DirectoryTaxonomyWriter(taxoDir, OpenMode.CREATE_OR_APPEND);

        List<Book> books = Arrays.asList(new Book("Tom Sawyer", "Mark Twain", "1840", "Novel"), new Book("Collected Tales",

                "Mark Twain", "1850", "Novel"), new Book("The Trial", "Franz Kafka", "1901", "Novel"), new Book("Some book",

                "Some author", "1901", "Novel"));

        createDocuments(writer, taxoWriter, books);

        taxoWriter.commit();

        writer.commit();

        writer.close();

        taxoWriter.close();

        IndexReader indexReader = DirectoryReader.open(dir);

        IndexSearcher searcher = new IndexSearcher(indexReader);

        TaxonomyReader taxoReader = new DirectoryTaxonomyReader(taxoDir);

        Query q = new TermQuery(new Term("category", "Novel"));

        TopScoreDocCollector tdc = TopScoreDocCollector.create(10, true);

        FacetSearchParams facetSearchParams = new FacetSearchParams();

        facetSearchParams.addFacetRequest(new CountFacetRequest(new CategoryPath("author"), 10));

        facetSearchParams.addFacetRequest(new CountFacetRequest(new CategoryPath("category"), 10));

        facetSearchParams.addFacetRequest(new CountFacetRequest(new CategoryPath("published"), 10));

        FacetsCollector facetsCollector = new FacetsCollector(facetSearchParams, indexReader, taxoReader);

        searcher.search(q, MultiCollector.wrap(tdc, facetsCollector));

        List<FacetResult> res = facetsCollector.getFacetResults();

        System.out.println("Search for books with the category:Novel returned : " + res.size()

                + " results\n---------------------------------");

        for (final FacetResult r : res) {

            System.out.println("\nMatching " + r.getFacetResultNode().getLabel() + ":\n------------------------------------");

            for (FacetResultNode n : r.getFacetResultNode().getSubResults()) {

                System.out.println(String.format("\t%s: %.0f", n.getLabel().lastComponent(), n.getValue()));

            }

        }

    }

    private static void createDocuments(final IndexWriter writer, final TaxonomyWriter taxoWriter, final List<Book> books)

            throws IOException {

        for (final Book b : books) {

            Document doc = new Document();

            doc.add(new StringField("title", b.getTitle(), Store.YES));

            doc.add(new StringField("category", b.getCategory(), Store.YES));

            List<CategoryPath> categories = new ArrayList<CategoryPath>();

            categories.add(new CategoryPath("author", b.getAuthor()));

            categories.add(new CategoryPath("category", b.getCategory()));

            categories.add(new CategoryPath("published", b.getPublished()));

            CategoryDocumentBuilder categoryDocBuilder = new CategoryDocumentBuilder(taxoWriter);

            categoryDocBuilder.setCategoryPaths(categories);

            categoryDocBuilder.build(doc);

            writer.addDocument(doc);

        }

    }

}

class Book {

    private final String title;

    private final String author;

    private final String published;

    private final String category;

    public Book(final String title, final String author, final String published, final String category) {

        this.title = title;

        this.author = author;

        this.published = published;

        this.category = category;

    }

    public String getTitle() {

        return title;

    }

    public String getAuthor() {

        return author;

    }

    public String getPublished() {

        return published;

    }

    public String getCategory() {

        return category;

    }

}

Search for books with the category:Novel returned : 3 results

---------------------------------

Matching author:

------------------------------------

    Mark Twain: 2

    Some author: 1

    Franz Kafka: 1

Matching category:

------------------------------------

    Novel: 4

Matching published:

------------------------------------

    1901: 2

    1850: 1

    1840: 1