HSEARCH-2281 Omit the "fuzziness" attribute on queries when not required

Author: yrodiere

elasticsearch/src/main/java/org/hibernate/search/elasticsearch/impl/ToElasticsearch.java

@@ -51,7 +51,7 @@ public class ToElasticsearch {
 	private static final Log LOG = LoggerFactory.make( Log.class );
 
 	private static final int DEFAULT_SLOP = 0;
-
+	private static final int DEFAULT_MAX_EDIT_DISTANCE = 0;
 	private static final float DEFAULT_BOOST = 1.0f;
 
 	private ToElasticsearch() {
@@ -347,7 +347,7 @@ private static JsonObject convertRemoteMatchQuery(RemoteMatchQuery query) {
 								JsonBuilder.object()
 										.addProperty( "query", query.getSearchTerms() )
 										.addProperty( "analyzer", query.getAnalyzerReference().getAnalyzer().getName( query.getField() ) )
-										.addProperty( "fuzziness", query.getMaxEditDistance() )
+										.append( fuzzinessAppender( query.getMaxEditDistance() ) )
 										.append( boostAppender( query ) )
 						)
 				).build();
@@ -484,6 +484,23 @@ public void append(JsonBuilder.Object object) {
 		}
 	}
 
+	/**
+	 * Appender that adds a "fuzziness" property if necessary.
+	 */
+	private static JsonBuilder.JsonAppender<? super JsonBuilder.Object> fuzzinessAppender(final int maxEditDistance) {
+		if ( maxEditDistance != DEFAULT_MAX_EDIT_DISTANCE ) {
+			return new JsonBuilder.JsonAppender<JsonBuilder.Object>() {
+				@Override
+				public void append(JsonBuilder.Object object) {
+					object.addProperty( "fuzziness", maxEditDistance );
+				}
+			};
+		}
+		else {
+			return NOOP_APPENDER;
+		}
+	}
+
 	/**
 	 * Appender that adds a "boost" property if necessary.
 	 */

elasticsearch/src/test/java/org/hibernate/search/elasticsearch/test/ElasticsearchDSLIT.java

@@ -99,7 +99,27 @@ public void testDSLKeyword() throws Exception {
 
 			FullTextQuery fullTextQuery = fullTextSession.createFullTextQuery( query, Letter.class );
 			String queryString = fullTextQuery.getQueryString();
-			assertJsonEquals( "{'query':{'match':{'message':{'query':'A very important matter','analyzer':'english','fuzziness':0}}}}", queryString );
+			assertJsonEquals( "{'query':{'match':{'message':{'query':'A very important matter','analyzer':'english'}}}}", queryString );
+		}
+	}
+
+	@Test
+	public void testDSLKeywordWithFuzziness() throws Exception {
+		try ( Session session = openSession() ) {
+			FullTextSession fullTextSession = Search.getFullTextSession( session );
+			final QueryBuilder queryBuilder = queryBuilder( fullTextSession );
+
+			Query query = queryBuilder
+					.keyword()
+						.fuzzy()
+							.withEditDistanceUpTo( 2 )
+						.onField( "message" )
+						.matching( "A very important matter" )
+					.createQuery();
+
+			FullTextQuery fullTextQuery = fullTextSession.createFullTextQuery( query, Letter.class );
+			String queryString = fullTextQuery.getQueryString();
+			assertJsonEquals( "{'query':{'match':{'message':{'query':'A very important matter','analyzer':'english','fuzziness':2}}}}", queryString );
 		}
 	}
 
@@ -118,7 +138,7 @@ public void testDSLKeywordWithBoost() throws Exception {
 
 			FullTextQuery fullTextQuery = fullTextSession.createFullTextQuery( query, Letter.class );
 			String queryString = fullTextQuery.getQueryString();
-			assertJsonEquals( "{'query':{'match':{'message':{'query':'A very important matter','analyzer':'english','fuzziness':0,'boost':2.0}}}}", queryString );
+			assertJsonEquals( "{'query':{'match':{'message':{'query':'A very important matter','analyzer':'english','boost':2.0}}}}", queryString );
 		}
 	}