RAMDirectory directory = new RAMDirectory();
String[] categories = new String[] {"/Computers/Linux",
"/Computers/Mac/One",
"/Computers/Mac/Two",
"/Computers/Windows"};
IndexWriter writer = new IndexWriter(directory, new WhitespaceAnalyzer(), true);
for (int i = 0; i < categories.length; i++) {
Document doc = new Document();
doc.add(new Field("category", categories[i], Field.Store.YES, Field.Index.UN_TOKENIZED));
writer.addDocument(doc);
}
writer.close();
// PrefixFilter combined with ConstantScoreQuery
PrefixFilter filter = new PrefixFilter(new Term("category", "/Computers"));
Query query = new ConstantScoreQuery(filter);
IndexSearcher searcher = new IndexSearcher(directory);
Hits hits = searcher.search(query);
assertEquals(4, hits.length());
// test middle of values
filter = new PrefixFilter(new Term("category", "/Computers/Mac"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(2, hits.length());
// test start of values
filter = new PrefixFilter(new Term("category", "/Computers/Linux"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(1, hits.length());
// test end of values
filter = new PrefixFilter(new Term("category", "/Computers/Windows"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(1, hits.length());
// test non-existant
filter = new PrefixFilter(new Term("category", "/Computers/ObsoleteOS"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(0, hits.length());
// test non-existant, before values
filter = new PrefixFilter(new Term("category", "/Computers/AAA"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(0, hits.length());
// test non-existant, after values
filter = new PrefixFilter(new Term("category", "/Computers/ZZZ"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(0, hits.length());
// test zero length prefix
filter = new PrefixFilter(new Term("category", ""));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(4, hits.length());
// test non existent field
filter = new PrefixFilter(new Term("nonexistantfield", "/Computers"));
query = new ConstantScoreQuery(filter);
hits = searcher.search(query);
assertEquals(0, hits.length());
