Class | Description |
---|---|
CollationAttributeFactory |
Converts each token into its
CollationKey , and then
encodes the bytes as an index term. |
CollationKeyAnalyzer |
Configures
KeywordTokenizer with CollationAttributeFactory . |
CollationKeyFilter | Deprecated
Use
CollationAttributeFactory instead, which encodes
terms directly as bytes. |
CollationKeyFilterFactory | Deprecated
use
CollationKeyAnalyzer instead. |
Unicode collation support.
Collation
converts each token into its binary CollationKey
using the
provided Collator
, allowing it to be stored as an index term.
LowerCaseFilter
and
ASCIIFoldingFilter
provide these services
in a generic way that doesn't take into account locale-specific needs.)
// "fa" Locale is not supported by Sun JDK 1.4 or 1.5 Collator collator = Collator.getInstance(new Locale("ar")); CollationKeyAnalyzer analyzer = new CollationKeyAnalyzer(version, collator); RAMDirectory ramDir = new RAMDirectory(); IndexWriter writer = new IndexWriter(ramDir, new IndexWriterConfig(version, analyzer)); Document doc = new Document(); doc.add(new TextField("content", "\u0633\u0627\u0628", Field.Store.YES)); writer.addDocument(doc); writer.close(); IndexReader ir = DirectoryReader.open(ramDir); IndexSearcher is = new IndexSearcher(ir); QueryParser aqp = new QueryParser(version, "content", analyzer); aqp.setAnalyzeRangeTerms(true); // Unicode order would include U+0633 in [ U+062F - U+0698 ], but Farsi // orders the U+0698 character before the U+0633 character, so the single // indexed Term above should NOT be returned by a ConstantScoreRangeQuery // with a Farsi Collator (or an Arabic one for the case when Farsi is not // supported). ScoreDoc[] result = is.search(aqp.parse("[ \u062F TO \u0698 ]"), null, 1000).scoreDocs; assertEquals("The index Term should not be included.", 0, result.length);
Analyzer analyzer = new CollationKeyAnalyzer(version, Collator.getInstance(new Locale("da", "dk"))); RAMDirectory indexStore = new RAMDirectory(); IndexWriter writer = new IndexWriter(indexStore, new IndexWriterConfig(version, analyzer)); String[] tracer = new String[] { "A", "B", "C", "D", "E" }; String[] data = new String[] { "HAT", "HUT", "H\u00C5T", "H\u00D8T", "HOT" }; String[] sortedTracerOrder = new String[] { "A", "E", "B", "D", "C" }; for (int i = 0 ; i < data.length ; ++i) { Document doc = new Document(); doc.add(new StoredField("tracer", tracer[i])); doc.add(new TextField("contents", data[i], Field.Store.NO)); writer.addDocument(doc); } writer.close(); IndexReader ir = DirectoryReader.open(indexStore); IndexSearcher searcher = new IndexSearcher(ir); Sort sort = new Sort(); sort.setSort(new SortField("contents", SortField.STRING)); Query query = new MatchAllDocsQuery(); ScoreDoc[] result = searcher.search(query, null, 1000, sort).scoreDocs; for (int i = 0 ; i < result.length ; ++i) { Document doc = searcher.doc(result[i].doc); assertEquals(sortedTracerOrder[i], doc.getValues("tracer")[0]); }
Collator collator = Collator.getInstance(new Locale("tr", "TR")); collator.setStrength(Collator.PRIMARY); Analyzer analyzer = new CollationKeyAnalyzer(version, collator); RAMDirectory ramDir = new RAMDirectory(); IndexWriter writer = new IndexWriter(ramDir, new IndexWriterConfig(version, analyzer)); Document doc = new Document(); doc.add(new TextField("contents", "DIGY", Field.Store.NO)); writer.addDocument(doc); writer.close(); IndexReader ir = DirectoryReader.open(ramDir); IndexSearcher is = new IndexSearcher(ir); QueryParser parser = new QueryParser(version, "contents", analyzer); Query query = parser.parse("d\u0131gy"); // U+0131: dotless i ScoreDoc[] result = is.search(query, null, 1000).scoreDocs; assertEquals("The index Term should be included.", 1, result.length);
WARNING: Make sure you use exactly the same
Collator
at index and query time -- CollationKey
s
are only comparable when produced by
the same Collator
. Since RuleBasedCollator
s
are not independently versioned, it is unsafe to search against stored
CollationKey
s unless the following are exactly the same (best
practice is to store this information with the index and check that they
remain the same at query time):
Collator.getInstance(java.util.Locale)
.
Collator.setStrength(int)
ICUCollationKeyAnalyzer
, available in the icu analysis module,
uses ICU4J's Collator
, which
makes its version available, thus allowing collation to be versioned
independently from the JVM. ICUCollationKeyAnalyzer
is also
significantly faster and generates significantly shorter keys than
CollationKeyAnalyzer
. See
http://site.icu-project.org/charts/collation-icu4j-sun for key
generation timing and key length comparisons between ICU4J and
java.text.Collator
over several languages.
CollationKey
s generated by java.text.Collator
s are
not compatible with those those generated by ICU Collators. Specifically, if
you use CollationKeyAnalyzer
to generate index terms, do not use
ICUCollationKeyAnalyzer
on the query side, or vice versa.
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