HSEARCH-4843 Remove generics for entity references in loading code

1. Because even currently, those generics are just for show: we end up
   with an unchecked cast in the backend.
2. Because we will ultimately use a single EntityReference type.

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/ElasticsearchExtension.java

@@ -112,7 +112,7 @@ public Optional<ElasticsearchSearchQuerySelectStep<R, E, LOS>> extendOptional(
 			SearchQuerySelectStep<?, R, E, LOS, ?, ?> original,
 			SearchQueryIndexScope<?> scope,
 			BackendSessionContext sessionContext,
-			SearchLoadingContextBuilder<R, E, LOS> loadingContextBuilder) {
+			SearchLoadingContextBuilder<E, LOS> loadingContextBuilder) {
 		if ( scope instanceof ElasticsearchSearchQueryIndexScope ) {
 			return Optional.of( new ElasticsearchSearchQuerySelectStepImpl<>(
 					(ElasticsearchSearchQueryIndexScope<?>) scope, sessionContext, loadingContextBuilder
@@ -128,7 +128,7 @@ public Optional<ElasticsearchSearchQuerySelectStep<R, E, LOS>> extendOptional(
 	 */
 	@Override
 	public Optional<ElasticsearchSearchQuery<H>> extendOptional(SearchQuery<H> original,
-			SearchLoadingContext<?, ?> loadingContext) {
+			SearchLoadingContext<?> loadingContext) {
 		if ( original instanceof ElasticsearchSearchQuery ) {
 			return Optional.of( (ElasticsearchSearchQuery<H>) original );
 		}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/index/impl/IndexManagerBackendContext.java

@@ -153,7 +153,7 @@ public ElasticsearchSearchQueryIndexScope<?> createSearchContext(BackendMappingC
 	public <H> ElasticsearchSearchQueryBuilder<H> createSearchQueryBuilder(
 			ElasticsearchSearchIndexScope<?> scope,
 			BackendSessionContext sessionContext,
-			SearchLoadingContextBuilder<?, ?, ?> loadingContextBuilder,
+			SearchLoadingContextBuilder<?, ?> loadingContextBuilder,
 			ElasticsearchSearchProjection<H> rootProjection) {
 		multiTenancyStrategy.documentIdHelper().checkTenantId( sessionContext.tenantIdentifier(), eventContext );
 		return new ElasticsearchSearchQueryBuilder<>(

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/scope/model/impl/ElasticsearchSearchIndexScopeImpl.java

@@ -168,7 +168,7 @@ public ElasticsearchSearchAggregationBuilderFactory aggregationBuilders() {
 
 	@Override
 	public <P> ElasticsearchSearchQueryBuilder<P> select(BackendSessionContext sessionContext,
-			SearchLoadingContextBuilder<?, ?, ?> loadingContextBuilder, SearchProjection<P> projection) {
+			SearchLoadingContextBuilder<?, ?> loadingContextBuilder, SearchProjection<P> projection) {
 		return backendContext.createSearchQueryBuilder( this, sessionContext, loadingContextBuilder,
 				ElasticsearchSearchProjection.from( this, projection ) );
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/AccumulatingSourceExtractor.java

@@ -35,14 +35,14 @@ public AccumulatingSourceExtractor(String[] fieldPathComponents,
 	}
 
 	@Override
-	public final A extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public final A extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		A accumulated = accumulator.createInitial();
 		accumulated = collect( projectionHitMapper, hit, source, context, accumulated, 0 );
 		return accumulated;
 	}
 
-	private A collect(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	private A collect(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject parent, ProjectionExtractContext context,
 			A accumulated, int currentPathComponentIndex) {
 		if ( parent == null ) {
@@ -77,7 +77,7 @@ else if ( child.isJsonArray() ) {
 		}
 	}
 
-	private A collectTargetField(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit, JsonElement fieldValue,
+	private A collectTargetField(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit, JsonElement fieldValue,
 			ProjectionExtractContext context, A accumulated) {
 		if ( fieldValue == null ) {
 			// Not present
@@ -99,7 +99,7 @@ else if ( fieldValue.isJsonArray() ) {
 		}
 	}
 
-	protected abstract E extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	protected abstract E extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonElement sourceElement, ProjectionExtractContext context);
 
 	private JsonObject toJsonObject(JsonElement childElement, int currentPathComponentIndex) {

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchByMappedTypeProjection.java

@@ -65,7 +65,7 @@ public String toString() {
 		}
 
 		@Override
-		public DelegateAndExtractedValue<?, P> extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+		public DelegateAndExtractedValue<?, P> extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 				JsonObject source, ProjectionExtractContext context) {
 			String typeName = mappedTypeNameHelper.extract( hit, context );
 			Extractor<?, ? extends P> inner = inners.get( typeName );
@@ -76,7 +76,7 @@ public DelegateAndExtractedValue<?, P> extract(ProjectionHitMapper<?, ?> project
 		}
 
 		@Override
-		public P transform(LoadingResult<?, ?> loadingResult, DelegateAndExtractedValue<?, P> extracted,
+		public P transform(LoadingResult<?> loadingResult, DelegateAndExtractedValue<?, P> extracted,
 				ProjectionTransformContext context) {
 			return extracted.transform( loadingResult, context );
 		}
@@ -87,13 +87,13 @@ private static final class DelegateAndExtractedValue<E, P> {
 		private final E extractedValue;
 
 		private DelegateAndExtractedValue(Extractor<E, ? extends P> delegate,
-				ProjectionHitMapper<?, ?> projectionHitMapper,
+				ProjectionHitMapper<?> projectionHitMapper,
 				JsonObject hit, JsonObject source, ProjectionExtractContext context) {
 			this.delegate = delegate;
 			this.extractedValue = delegate.extract( projectionHitMapper, hit, source, context );
 		}
 
-		P transform(LoadingResult<?, ?> loadingResult, ProjectionTransformContext context) {
+		P transform(LoadingResult<?> loadingResult, ProjectionTransformContext context) {
 			return delegate.transform( loadingResult, extractedValue, context );
 		}
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchCompositeProjection.java

@@ -78,7 +78,7 @@ public String toString() {
 		}
 
 		@Override
-		public A extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+		public A extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 				JsonObject source, ProjectionExtractContext context) {
 			A accumulated = accumulator.createInitial();
 
@@ -93,7 +93,7 @@ public A extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
 		}
 
 		@Override
-		public final P transform(LoadingResult<?, ?> loadingResult, A accumulated,
+		public final P transform(LoadingResult<?> loadingResult, A accumulated,
 				ProjectionTransformContext context) {
 			for ( int i = 0; i < accumulator.size( accumulated ); i++ ) {
 				E transformedData = accumulator.get( accumulated, i );

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchConstantProjection.java

@@ -28,13 +28,13 @@ public Extractor<?, T> request(JsonObject requestBody, ProjectionRequestContext
 
 
 	@Override
-	public T extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit, JsonObject source,
+	public T extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit, JsonObject source,
 			ProjectionExtractContext context) {
 		return value;
 	}
 
 	@Override
-	public T transform(LoadingResult<?, ?> loadingResult, T extractedData, ProjectionTransformContext context) {
+	public T transform(LoadingResult<?> loadingResult, T extractedData, ProjectionTransformContext context) {
 		return extractedData;
 	}
 

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchDistanceToFieldProjection.java

@@ -125,7 +125,7 @@ else if ( scriptFieldName != null ) {
 	}
 
 	@Override
-	public A extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public A extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		Integer distanceSortIndex = singleValuedInRoot ? context.getDistanceSortIndex( absoluteFieldPath, center ) : null;
 
@@ -142,7 +142,7 @@ public A extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
 	}
 
 	@Override
-	public P transform(LoadingResult<?, ?> loadingResult, A extractedData,
+	public P transform(LoadingResult<?> loadingResult, A extractedData,
 			ProjectionTransformContext context) {
 		// Nothing to transform: we take the values as they are.
 		return accumulator.finish( extractedData );

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchDocumentReferenceProjection.java

@@ -43,13 +43,13 @@ public Extractor<?, DocumentReference> request(JsonObject requestBody, Projectio
 	}
 
 	@Override
-	public DocumentReference extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public DocumentReference extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return helper.extract( hit, context );
 	}
 
 	@Override
-	public DocumentReference transform(LoadingResult<?, ?> loadingResult, DocumentReference extractedData,
+	public DocumentReference transform(LoadingResult<?> loadingResult, DocumentReference extractedData,
 			ProjectionTransformContext context) {
 		return extractedData;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchEntityLoadingProjection.java

@@ -41,14 +41,14 @@ public Extractor<?, E> request(JsonObject requestBody, ProjectionRequestContext
 	}
 
 	@Override
-	public Object extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public Object extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return projectionHitMapper.planLoading( helper.extract( hit, context ) );
 	}
 
 	@SuppressWarnings("unchecked")
 	@Override
-	public E transform(LoadingResult<?, ?> loadingResult, Object extractedData,
+	public E transform(LoadingResult<?> loadingResult, Object extractedData,
 			ProjectionTransformContext context) {
 		E loaded = (E) loadingResult.get( extractedData );
 		if ( loaded == null ) {

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchEntityReferenceProjection.java

@@ -41,14 +41,14 @@ public Extractor<?, R> request(JsonObject requestBody, ProjectionRequestContext
 	}
 
 	@Override
-	public DocumentReference extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public DocumentReference extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return helper.extract( hit, context );
 	}
 
 	@Override
 	@SuppressWarnings("unchecked")
-	public R transform(LoadingResult<?, ?> loadingResult, DocumentReference extractedData,
+	public R transform(LoadingResult<?> loadingResult, DocumentReference extractedData,
 			ProjectionTransformContext context) {
 		return (R) loadingResult.convertReference( extractedData );
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchExplanationProjection.java

@@ -41,14 +41,14 @@ public Extractor<?, JsonObject> request(JsonObject requestBody, ProjectionReques
 	}
 
 	@Override
-	public JsonObject extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public JsonObject extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		// We expect the optional to always be non-empty.
 		return HIT_EXPLANATION_ACCESSOR.get( hit ).get();
 	}
 
 	@Override
-	public JsonObject transform(LoadingResult<?, ?> loadingResult, JsonObject extractedData,
+	public JsonObject transform(LoadingResult<?> loadingResult, JsonObject extractedData,
 			ProjectionTransformContext context) {
 		return extractedData;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchFieldHighlightProjection.java

@@ -109,7 +109,7 @@ private FieldHighlightExtractor(String fieldPath) {
 		}
 
 		@Override
-		public List<String> extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit, JsonObject source,
+		public List<String> extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit, JsonObject source,
 				ProjectionExtractContext context) {
 			Optional<JsonArray> highlights = highlightAccessor.get( hit );
 			if ( highlights.isPresent() ) {
@@ -123,7 +123,7 @@ public List<String> extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonO
 		}
 
 		@Override
-		public List<String> transform(LoadingResult<?, ?> loadingResult, List<String> extractedData,
+		public List<String> transform(LoadingResult<?> loadingResult, List<String> extractedData,
 				ProjectionTransformContext context) {
 			return extractedData;
 		}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchFieldProjection.java

@@ -104,13 +104,13 @@ public String toString() {
 		}
 
 		@Override
-		protected F extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit, JsonElement sourceElement,
+		protected F extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit, JsonElement sourceElement,
 				ProjectionExtractContext context) {
 			return decodeFunction.apply( sourceElement );
 		}
 
 		@Override
-		public P transform(LoadingResult<?, ?> loadingResult, A extractedData,
+		public P transform(LoadingResult<?> loadingResult, A extractedData,
 				ProjectionTransformContext context) {
 			FromDocumentValueConvertContext convertContext = context.fromDocumentValueConvertContext();
 			A transformedData = accumulator.transformAll( extractedData, converter, convertContext );

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchIdProjection.java

@@ -45,13 +45,13 @@ public Extractor<?, I> request(JsonObject requestBody, ProjectionRequestContext
 	}
 
 	@Override
-	public String extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public String extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return extractionHelper.extract( hit, context );
 	}
 
 	@Override
-	public I transform(LoadingResult<?, ?> loadingResult, String extractedData,
+	public I transform(LoadingResult<?> loadingResult, String extractedData,
 			ProjectionTransformContext context) {
 		return converter.fromDocumentValue( extractedData, context.fromDocumentValueConvertContext() );
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchJsonHitProjection.java

@@ -35,13 +35,13 @@ public Extractor<?, JsonObject> request(JsonObject requestBody, ProjectionReques
 	}
 
 	@Override
-	public JsonObject extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public JsonObject extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return hit;
 	}
 
 	@Override
-	public JsonObject transform(LoadingResult<?, ?> loadingResult, JsonObject extractedData,
+	public JsonObject transform(LoadingResult<?> loadingResult, JsonObject extractedData,
 			ProjectionTransformContext context) {
 		return extractedData;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchObjectProjection.java

@@ -102,7 +102,7 @@ public String toString() {
 		}
 
 		@Override
-		protected E extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit, JsonElement sourceElement,
+		protected E extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit, JsonElement sourceElement,
 				ProjectionExtractContext context) {
 			if ( sourceElement == null || sourceElement.isJsonNull() ) {
 				return null;
@@ -117,7 +117,7 @@ protected E extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hi
 		}
 
 		@Override
-		public final P transform(LoadingResult<?, ?> loadingResult, A accumulated,
+		public final P transform(LoadingResult<?> loadingResult, A accumulated,
 				ProjectionTransformContext context) {
 			for ( int i = 0; i < accumulator.size( accumulated ); i++ ) {
 				E transformedData = accumulator.get( accumulated, i );

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchScoreProjection.java

@@ -41,13 +41,13 @@ public Extractor<?, Float> request(JsonObject requestBody, ProjectionRequestCont
 	}
 
 	@Override
-	public Float extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public Float extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return hit.get( "_score" ).getAsFloat();
 	}
 
 	@Override
-	public Float transform(LoadingResult<?, ?> loadingResult, Float extractedData,
+	public Float transform(LoadingResult<?> loadingResult, Float extractedData,
 			ProjectionTransformContext context) {
 		return extractedData;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchSearchProjection.java

@@ -61,7 +61,7 @@ interface Extractor<E, P> {
 		 * {@link ProjectionHitMapper}.
 		 * This returned object will be passed to {@link #transform(LoadingResult, Object, ProjectionTransformContext)}.
 		 */
-		E extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+		E extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 				JsonObject source, ProjectionExtractContext context);
 
 		/**
@@ -74,15 +74,15 @@ E extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
 		 * @param context An execution context for the transforming.
 		 * @return The final result considered as a hit.
 		 */
-		P transform(LoadingResult<?, ?> loadingResult, E extractedData, ProjectionTransformContext context);
+		P transform(LoadingResult<?> loadingResult, E extractedData, ProjectionTransformContext context);
 
 		/**
 		 * Transforms the extracted data and casts it to the right type.
 		 * <p>
 		 * This should be used with care as it's unsafe.
 		 */
 		@SuppressWarnings({ "unchecked", "rawtypes" })
-		static <Z> Z transformUnsafe(Extractor<?, Z> extractor, LoadingResult<?, ?> loadingResult,
+		static <Z> Z transformUnsafe(Extractor<?, Z> extractor, LoadingResult<?> loadingResult,
 				Object extractedData, ProjectionTransformContext context) {
 			return (Z) ( (Extractor) extractor ).transform( loadingResult, extractedData, context );
 		}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchSourceProjection.java

@@ -42,13 +42,13 @@ public Extractor<?, JsonObject> request(JsonObject requestBody, ProjectionReques
 	}
 
 	@Override
-	public JsonObject extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit,
+	public JsonObject extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit,
 			JsonObject source, ProjectionExtractContext context) {
 		return source;
 	}
 
 	@Override
-	public JsonObject transform(LoadingResult<?, ?> loadingResult, JsonObject extractedData,
+	public JsonObject transform(LoadingResult<?> loadingResult, JsonObject extractedData,
 			ProjectionTransformContext context) {
 		return extractedData;
 	}

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/projection/impl/ElasticsearchThrowingProjection.java

@@ -31,13 +31,13 @@ public Extractor<?, T> request(JsonObject requestBody, ProjectionRequestContext
 	}
 
 	@Override
-	public Object extract(ProjectionHitMapper<?, ?> projectionHitMapper, JsonObject hit, JsonObject source,
+	public Object extract(ProjectionHitMapper<?> projectionHitMapper, JsonObject hit, JsonObject source,
 			ProjectionExtractContext context) {
 		throw exceptionSupplier.get();
 	}
 
 	@Override
-	public T transform(LoadingResult<?, ?> loadingResult, Object extractedData, ProjectionTransformContext context) {
+	public T transform(LoadingResult<?> loadingResult, Object extractedData, ProjectionTransformContext context) {
 		throw exceptionSupplier.get();
 	}
 }

backend/elasticsearch/src/main/java/org/hibernate/search/backend/elasticsearch/search/query/dsl/impl/ElasticsearchSearchQueryOptionsStepImpl.java

@@ -39,7 +39,7 @@ class ElasticsearchSearchQueryOptionsStepImpl<H, LOS>
 
 	ElasticsearchSearchQueryOptionsStepImpl(ElasticsearchSearchQueryIndexScope<?> scope,
 			ElasticsearchSearchQueryBuilder<H> searchQueryBuilder,
-			SearchLoadingContextBuilder<?, ?, LOS> loadingContextBuilder) {
+			SearchLoadingContextBuilder<?, LOS> loadingContextBuilder) {
 		super( scope, searchQueryBuilder, loadingContextBuilder );
 		this.searchQueryBuilder = searchQueryBuilder;
 	}