Lucene8：Facetの使い方サンプル、その2

2020年1月21日

int, longの場合はfacet用ディレクトリは不要のようだ。そして、intもlongもlongとして扱われるらしい（そもそもlongしか無い？）。

import static java.util.stream.Collectors.*;
import static org.junit.Assert.*;

import java.util.stream.*;

import org.apache.lucene.document.*;
import org.apache.lucene.facet.*;
import org.apache.lucene.index.*;
import org.apache.lucene.search.*;
import org.apache.lucene.store.*;
import org.junit.*;

public class FacetTest2 {

  @Test
  public void test() throws Exception {

    Directory dir = new RAMDirectory();

    try (IndexWriter indexWriter = new IndexWriter(dir, new IndexWriterConfig())) {
      for (int i = 0; i < 10; i++) {
        Document doc = new Document();
        doc.add(new NumericDocValuesField("id", 1));
        indexWriter.addDocument(doc);
      }
      for (int i = 0; i < 5; i++) {
        Document doc = new Document();
        doc.add(new NumericDocValuesField("id", 2));
        indexWriter.addDocument(doc);      
      }
    }

    try (IndexReader indexReader = DirectoryReader.open(dir)) {

      IndexSearcher indexSearcher = new IndexSearcher(indexReader);      
      FacetsCollector fc = new FacetsCollector();      
      FacetsCollector.search(indexSearcher, new MatchAllDocsQuery(), Integer.MAX_VALUE, fc);       

      LongValueFacetCounts longCounts = new LongValueFacetCounts("id", fc, false);       
      FacetResult result = longCounts.getAllChildrenSortByValue();

      String s = IntStream.range(0, result.childCount)
        .mapToObj(i->result.labelValues[i])
        .map(lv->lv.label + "=" + lv.value)
        .sorted()
        .collect(joining(","));

      assertEquals("1=10,2=5", s);
    }    
  }
}