Expose Japanese completion filter to kuromoji analysis plugin (#81858)

This adds analysis factories of JapaneseCompletionFilter and JapaneseCompletionAnalyzer (https://issues.apache.org/jira/browse/LUCENE-10102) to the kuromoji plugin.

plugins/analysis-kuromoji/src/main/java/org/elasticsearch/plugin/analysis/kuromoji/AnalysisKuromojiPlugin.java

@@ -37,6 +37,7 @@ public Map<String, AnalysisProvider<TokenFilterFactory>> getTokenFilters() {
         extra.put("kuromoji_stemmer", KuromojiKatakanaStemmerFactory::new);
         extra.put("ja_stop", JapaneseStopTokenFilterFactory::new);
         extra.put("kuromoji_number", KuromojiNumberFilterFactory::new);
+        extra.put("kuromoji_completion", KuromojiCompletionFilterFactory::new);
         return extra;
     }
 
@@ -47,6 +48,9 @@ public Map<String, AnalysisProvider<TokenizerFactory>> getTokenizers() {
 
     @Override
     public Map<String, AnalysisProvider<AnalyzerProvider<? extends Analyzer>>> getAnalyzers() {
-        return singletonMap("kuromoji", KuromojiAnalyzerProvider::new);
+        Map<String, AnalysisProvider<AnalyzerProvider<? extends Analyzer>>> extra = new HashMap<>();
+        extra.put("kuromoji", KuromojiAnalyzerProvider::new);
+        extra.put("kuromoji_completion", KuromojiCompletionAnalyzerProvider::new);
+        return extra;
     }
 }

plugins/analysis-kuromoji/src/main/java/org/elasticsearch/plugin/analysis/kuromoji/KuromojiCompletionAnalyzerProvider.java

@@ -0,0 +1,34 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.plugin.analysis.kuromoji;
+
+import org.apache.lucene.analysis.ja.JapaneseCompletionAnalyzer;
+import org.apache.lucene.analysis.ja.JapaneseCompletionFilter.Mode;
+import org.apache.lucene.analysis.ja.dict.UserDictionary;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.index.IndexSettings;
+import org.elasticsearch.index.analysis.AbstractIndexAnalyzerProvider;
+
+public class KuromojiCompletionAnalyzerProvider extends AbstractIndexAnalyzerProvider<JapaneseCompletionAnalyzer> {
+
+    private final JapaneseCompletionAnalyzer analyzer;
+
+    public KuromojiCompletionAnalyzerProvider(IndexSettings indexSettings, Environment env, String name, Settings settings) {
+        super(indexSettings, name, settings);
+        final UserDictionary userDictionary = KuromojiTokenizerFactory.getUserDictionary(env, settings);
+        final Mode mode = KuromojiCompletionFilterFactory.getMode(settings);
+        analyzer = new JapaneseCompletionAnalyzer(userDictionary, mode);
+    }
+
+    @Override
+    public JapaneseCompletionAnalyzer get() {
+        return analyzer;
+    }
+}

plugins/analysis-kuromoji/src/main/java/org/elasticsearch/plugin/analysis/kuromoji/KuromojiCompletionFilterFactory.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.plugin.analysis.kuromoji;
+
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.ja.JapaneseCompletionFilter;
+import org.apache.lucene.analysis.ja.JapaneseCompletionFilter.Mode;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.env.Environment;
+import org.elasticsearch.index.IndexSettings;
+import org.elasticsearch.index.analysis.AbstractTokenFilterFactory;
+
+public class KuromojiCompletionFilterFactory extends AbstractTokenFilterFactory {
+
+    private final Mode mode;
+
+    public KuromojiCompletionFilterFactory(IndexSettings indexSettings, Environment env, String name, Settings settings) {
+        super(indexSettings, name, settings);
+        mode = getMode(settings);
+    }
+
+    public static JapaneseCompletionFilter.Mode getMode(Settings settings) {
+        JapaneseCompletionFilter.Mode mode = Mode.INDEX;
+        String modeSetting = settings.get("mode", null);
+        if (modeSetting != null) {
+            if ("index".equalsIgnoreCase(modeSetting)) {
+                mode = JapaneseCompletionFilter.Mode.INDEX;
+            } else if ("query".equalsIgnoreCase(modeSetting)) {
+                mode = JapaneseCompletionFilter.Mode.QUERY;
+            }
+        }
+        return mode;
+    }
+
+    @Override
+    public TokenStream create(TokenStream tokenStream) {
+        return new JapaneseCompletionFilter(tokenStream, mode);
+    }
+
+}

plugins/analysis-kuromoji/src/test/java/org/elasticsearch/plugin/analysis/kuromoji/KuromojiAnalysisTests.java

@@ -12,6 +12,7 @@
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ja.JapaneseAnalyzer;
+import org.apache.lucene.analysis.ja.JapaneseCompletionAnalyzer;
 import org.apache.lucene.analysis.ja.JapaneseTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.elasticsearch.Version;
@@ -67,10 +68,16 @@ public void testDefaultsKuromojiAnalysis() throws IOException {
         filterFactory = analysis.tokenFilter.get("kuromoji_number");
         assertThat(filterFactory, instanceOf(KuromojiNumberFilterFactory.class));
 
+        filterFactory = analysis.tokenFilter.get("kuromoji_completion");
+        assertThat(filterFactory, instanceOf(KuromojiCompletionFilterFactory.class));
+
         IndexAnalyzers indexAnalyzers = analysis.indexAnalyzers;
         NamedAnalyzer analyzer = indexAnalyzers.get("kuromoji");
         assertThat(analyzer.analyzer(), instanceOf(JapaneseAnalyzer.class));
 
+        analyzer = indexAnalyzers.get("kuromoji_completion");
+        assertThat(analyzer.analyzer(), instanceOf(JapaneseCompletionAnalyzer.class));
+
         analyzer = indexAnalyzers.get("my_analyzer");
         assertThat(analyzer.analyzer(), instanceOf(CustomAnalyzer.class));
         assertThat(analyzer.analyzer().tokenStream(null, new StringReader("")), instanceOf(JapaneseTokenizer.class));
@@ -225,6 +232,42 @@ public void testJapaneseStopFilterFactory() throws IOException {
         assertSimpleTSOutput(tokenFilter.create(tokenizer), expected);
     }
 
+    public void testCompletionFilterFactory() throws IOException {
+        // mode=INDEX
+        TestAnalysis analysis = createTestAnalysis();
+        TokenFilterFactory tokenFilter = analysis.tokenFilter.get("kuromoji_completion_index");
+        assertThat(tokenFilter, instanceOf(KuromojiCompletionFilterFactory.class));
+        String source = "東京都";
+        String[] expected_tokens = new String[] { "東京", "toukyou", "都", "to" };
+        Tokenizer tokenizer = new JapaneseTokenizer(null, true, JapaneseTokenizer.Mode.SEARCH);
+        tokenizer.setReader(new StringReader(source));
+        assertSimpleTSOutput(tokenFilter.create(tokenizer), expected_tokens);
+
+        // mode=QUERY
+        tokenFilter = analysis.tokenFilter.get("kuromoji_completion_query");
+        assertThat(tokenFilter, instanceOf(KuromojiCompletionFilterFactory.class));
+        source = "サッk";
+        expected_tokens = new String[] { "サッk", "sakk" };
+        tokenizer = new JapaneseTokenizer(null, true, JapaneseTokenizer.Mode.SEARCH);
+        tokenizer.setReader(new StringReader(source));
+        assertSimpleTSOutput(tokenFilter.create(tokenizer), expected_tokens);
+    }
+
+    public void testCompletionAnalyzer() throws IOException {
+        // mode=INDEX
+        TestAnalysis analysis = createTestAnalysis();
+        Analyzer analyzer = analysis.indexAnalyzers.get("completion_index_analyzer");
+        try (TokenStream stream = analyzer.tokenStream("", "ｿｰｽｺｰﾄﾞ")) {
+            assertTokenStreamContents(stream, new String[] { "ソース", "soーsu", "コード", "koーdo" });
+        }
+
+        // mode=QUERY
+        analyzer = analysis.indexAnalyzers.get("completion_query_analyzer");
+        try (TokenStream stream = analyzer.tokenStream("", "ｿｰｽｺｰﾄﾞ")) {
+            assertTokenStreamContents(stream, new String[] { "ソースコード", "soーsukoーdo" });
+        }
+    }
+
     private static TestAnalysis createTestAnalysis() throws IOException {
         InputStream empty_dict = KuromojiAnalysisTests.class.getResourceAsStream("empty_user_dict.txt");
         InputStream dict = KuromojiAnalysisTests.class.getResourceAsStream("user_dict.txt");

plugins/analysis-kuromoji/src/test/resources/org/elasticsearch/plugin/analysis/kuromoji/kuromoji_analysis.json

@@ -17,6 +17,14 @@
                 "ja_stop" : {
                     "type": "ja_stop",
                     "stopwords": ["_japanese_", "スピード"]
+                },
+                "kuromoji_completion_index" : {
+                    "type": "kuromoji_completion",
+                    "mode": "index"
+                },
+                "kuromoji_completion_query" : {
+                    "type": "kuromoji_completion",
+                    "mode": "query"
                 }
             },
 
@@ -70,6 +78,14 @@
                 "my_analyzer" : {
                     "type" : "custom",
                     "tokenizer" : "kuromoji_tokenizer"
+                },
+                "completion_index_analyzer" : {
+                    "type" : "kuromoji_completion",
+                    "mode" : "index"
+                },
+                "completion_query_analyzer" : {
+                    "type" : "kuromoji_completion",
+                    "mode" : "query"
                 }
             }
 

plugins/analysis-kuromoji/src/yamlRestTest/resources/rest-api-spec/test/analysis_kuromoji/10_basic.yml

@@ -57,3 +57,41 @@
             filter:       [kuromoji_stemmer]
     - length: { tokens: 1 }
     - match:  { tokens.0.token: サーバ }
+---
+"Completion analyzer":
+    - do:
+        indices.create:
+          index:  kuromoji_completion_sample
+          body:
+            settings:
+              index:
+                analysis:
+                  analyzer:
+                    completion_index:
+                      type: kuromoji_completion
+                      mode: index
+                    completion_query:
+                      type: kuromoji_completion
+                      mode: query
+
+    - do:
+        indices.analyze:
+          index: kuromoji_completion_sample
+          body:
+            text:         ｿｰｽｺｰﾄﾞ
+            analyzer:     completion_index
+    - length: { tokens: 4 }
+    - match:  { tokens.0.token: ソース }
+    - match:  { tokens.1.token: soーsu }
+    - match:  { tokens.2.token: コード }
+    - match:  { tokens.3.token: koーdo }
+
+    - do:
+        indices.analyze:
+          index: kuromoji_completion_sample
+          body:
+            text:         ｿｰｽｺｰﾄﾞ
+            analyzer:     completion_query
+    - length: { tokens: 2 }
+    - match:  { tokens.0.token: ソースコード }
+    - match:  { tokens.1.token: soーsukoーdo }