Introduce QueryEnhancerSelector to configure which `QueryEnhancerFa…

…ctory` to use.

Introduce QueryEnhancerSelector to EnableJpaRepositories.

Also, split DeclaredQuery into two interfaces to resolve the inner cycle of query introspection while just a value object is being created.

Introduce JpaQueryConfiguration to capture a multitude of configuration elements.

spring-data-jpa/src/jmh/java/org/springframework/data/jpa/repository/query/HqlParserBenchmarks.java

@@ -55,8 +55,8 @@ OR TREAT(p AS SmallProject).name LIKE 'Persist%'
 					    OR p.description LIKE "cost overrun"
 					""";
 
-			query = DeclaredQuery.of(s, false);
-			enhancer = QueryEnhancerFactory.forQuery(query);
+			query = DeclaredQuery.ofJpql(s);
+			enhancer = QueryEnhancerFactory.forQuery(query).create(query);
 		}
 	}
 

spring-data-jpa/src/jmh/java/org/springframework/data/jpa/repository/query/JSqlParserQueryEnhancerBenchmarks.java

@@ -56,7 +56,7 @@ public void doSetup() throws IOException {
 					select SOME_COLUMN from SOME_OTHER_TABLE where REPORTING_DATE = :REPORTING_DATE
 					union select SOME_COLUMN from SOME_OTHER_OTHER_TABLE""";
 
-			enhancer = new JSqlParserQueryEnhancer(DeclaredQuery.of(s, true));
+			enhancer = new JSqlParserQueryEnhancer(DeclaredQuery.ofNative(s));
 		}
 	}
 

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/config/EnableJpaRepositories.java

@@ -28,6 +28,7 @@
 import org.springframework.context.annotation.ComponentScan.Filter;
 import org.springframework.context.annotation.Import;
 import org.springframework.context.annotation.Lazy;
+import org.springframework.data.jpa.repository.query.QueryEnhancerSelector;
 import org.springframework.data.jpa.repository.support.JpaRepositoryFactoryBean;
 import org.springframework.data.repository.config.BootstrapMode;
 import org.springframework.data.repository.config.DefaultRepositoryBaseClass;
@@ -181,4 +182,11 @@
 	 * @return a single character used for escaping.
 	 */
 	char escapeCharacter() default '\\';
+
+	/**
+	 * Configures the {@link QueryEnhancerSelector} to select a query enhancer for query introspection and transformation.
+	 *
+	 * @return a {@link QueryEnhancerSelector} class providing a no-args constructor.
+	 */
+	Class<? extends QueryEnhancerSelector> queryEnhancerSelector() default QueryEnhancerSelector.DefaultQueryEnhancerSelector.class;
 }

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/config/JpaRepositoryConfigExtension.java

@@ -119,6 +119,11 @@ public void postProcess(BeanDefinitionBuilder builder, RepositoryConfigurationSo
 		builder.addPropertyReference("entityManager", entityManagerRefs.get(source));
 		builder.addPropertyValue(ESCAPE_CHARACTER_PROPERTY, getEscapeCharacter(source).orElse('\\'));
 		builder.addPropertyReference("mappingContext", JPA_MAPPING_CONTEXT_BEAN_NAME);
+
+		if (source instanceof AnnotationRepositoryConfigurationSource) {
+			builder.addPropertyValue("queryEnhancerSelector",
+					source.getAttribute("queryEnhancerSelector", Class.class).orElse(null));
+		}
 	}
 
 	@Override

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/AbstractStringBasedJpaQuery.java

@@ -48,8 +48,8 @@
  */
 abstract class AbstractStringBasedJpaQuery extends AbstractJpaQuery {
 
-	private final DeclaredQuery query;
-	private final Lazy<DeclaredQuery> countQuery;
+	private final StringQuery query;
+	private final Lazy<IntrospectedQuery> countQuery;
 	private final ValueExpressionDelegate valueExpressionDelegate;
 	private final QueryRewriter queryRewriter;
 	private final QuerySortRewriter querySortRewriter;
@@ -64,37 +64,32 @@ abstract class AbstractStringBasedJpaQuery extends AbstractJpaQuery {
 	 * @param em must not be {@literal null}.
 	 * @param queryString must not be {@literal null}.
 	 * @param countQueryString must not be {@literal null}.
-	 * @param queryRewriter must not be {@literal null}.
-	 * @param valueExpressionDelegate must not be {@literal null}.
+	 * @param queryConfiguration must not be {@literal null}.
 	 */
 	public AbstractStringBasedJpaQuery(JpaQueryMethod method, EntityManager em, String queryString,
-			@Nullable String countQueryString, QueryRewriter queryRewriter, ValueExpressionDelegate valueExpressionDelegate) {
+			@Nullable String countQueryString, JpaQueryConfiguration queryConfiguration) {
 
 		super(method, em);
 
 		Assert.hasText(queryString, "Query string must not be null or empty");
-		Assert.notNull(valueExpressionDelegate, "ValueExpressionDelegate must not be null");
-		Assert.notNull(queryRewriter, "QueryRewriter must not be null");
+		Assert.notNull(queryConfiguration, "JpaQueryConfiguration must not be null");
 
-		this.valueExpressionDelegate = valueExpressionDelegate;
+		this.valueExpressionDelegate = queryConfiguration.getValueExpressionDelegate();
 		this.valueExpressionContextProvider = valueExpressionDelegate.createValueContextProvider(method.getParameters());
-		this.query = new ExpressionBasedStringQuery(queryString, method.getEntityInformation(), valueExpressionDelegate,
-				method.isNativeQuery());
+		this.query = ExpressionBasedStringQuery.create(queryString, method, queryConfiguration);
 
 		this.countQuery = Lazy.of(() -> {
 
 			if (StringUtils.hasText(countQueryString)) {
-
-				return new ExpressionBasedStringQuery(countQueryString, method.getEntityInformation(), valueExpressionDelegate,
-						method.isNativeQuery());
+				return ExpressionBasedStringQuery.create(countQueryString, method, queryConfiguration);
 			}
 
-			return query.deriveCountQuery(method.getCountQueryProjection());
+			return this.query.deriveCountQuery(method.getCountQueryProjection());
 		});
 
 		this.countParameterBinder = Lazy.of(() -> this.createBinder(this.countQuery.get()));
 
-		this.queryRewriter = queryRewriter;
+		this.queryRewriter = queryConfiguration.getQueryRewriter(method);
 
 		JpaParameters parameters = method.getParameters();
 
@@ -108,7 +103,7 @@ public AbstractStringBasedJpaQuery(JpaQueryMethod method, EntityManager em, Stri
 			}
 		}
 
-		Assert.isTrue(method.isNativeQuery() || !query.usesJdbcStyleParameters(),
+		Assert.isTrue(method.isNativeQuery() || !this.query.usesJdbcStyleParameters(),
 				"JDBC style parameters (?) are not supported for JPA queries");
 	}
 
@@ -135,7 +130,7 @@ protected ParameterBinder createBinder() {
 		return createBinder(query);
 	}
 
-	protected ParameterBinder createBinder(DeclaredQuery query) {
+	protected ParameterBinder createBinder(IntrospectedQuery query) {
 		return ParameterBinderFactory.createQueryAwareBinder(getQueryMethod().getParameters(), query,
 				valueExpressionDelegate, valueExpressionContextProvider);
 	}
@@ -159,14 +154,14 @@ protected Query doCreateCountQuery(JpaParametersParameterAccessor accessor) {
 	/**
 	 * @return the query
 	 */
-	public DeclaredQuery getQuery() {
+	public EntityQuery getQuery() {
 		return query;
 	}
 
 	/**
 	 * @return the countQuery
 	 */
-	public DeclaredQuery getCountQuery() {
+	public IntrospectedQuery getCountQuery() {
 		return countQuery.get();
 	}
 
@@ -207,16 +202,15 @@ protected String potentiallyRewriteQuery(String originalQuery, Sort sort, @Nulla
 	}
 
 	String applySorting(CachableQuery cachableQuery) {
-
-		return QueryEnhancerFactory.forQuery(cachableQuery.getDeclaredQuery())
+		return cachableQuery.getDeclaredQuery().getQueryEnhancer()
 				.rewrite(new DefaultQueryRewriteInformation(cachableQuery.getSort(), cachableQuery.getReturnedType()));
 	}
 
 	/**
 	 * Query Sort Rewriter interface.
 	 */
 	interface QuerySortRewriter {
-		String getSorted(DeclaredQuery query, Sort sort, ReturnedType returnedType);
+		String getSorted(StringQuery query, Sort sort, ReturnedType returnedType);
 	}
 
 	/**
@@ -226,25 +220,24 @@ enum SimpleQuerySortRewriter implements QuerySortRewriter {
 
 		INSTANCE;
 
-		public String getSorted(DeclaredQuery query, Sort sort, ReturnedType returnedType) {
-
-			return QueryEnhancerFactory.forQuery(query).rewrite(new DefaultQueryRewriteInformation(sort, returnedType));
+		public String getSorted(StringQuery query, Sort sort, ReturnedType returnedType) {
+			return query.getQueryEnhancer().rewrite(new DefaultQueryRewriteInformation(sort, returnedType));
 		}
 	}
 
 	static class UnsortedCachingQuerySortRewriter implements QuerySortRewriter {
 
 		private volatile String cachedQueryString;
 
-		public String getSorted(DeclaredQuery query, Sort sort, ReturnedType returnedType) {
+		public String getSorted(StringQuery query, Sort sort, ReturnedType returnedType) {
 
 			if (sort.isSorted()) {
 				throw new UnsupportedOperationException("NoOpQueryCache does not support sorting");
 			}
 
 			String cachedQueryString = this.cachedQueryString;
 			if (cachedQueryString == null) {
-				this.cachedQueryString = cachedQueryString = QueryEnhancerFactory.forQuery(query)
+				this.cachedQueryString = cachedQueryString = query.getQueryEnhancer()
 						.rewrite(new DefaultQueryRewriteInformation(sort, returnedType));
 			}
 
@@ -263,7 +256,7 @@ class CachingQuerySortRewriter implements QuerySortRewriter {
 		private volatile String cachedQueryString;
 
 		@Override
-		public String getSorted(DeclaredQuery query, Sort sort, ReturnedType returnedType) {
+		public String getSorted(StringQuery query, Sort sort, ReturnedType returnedType) {
 
 			if (sort.isUnsorted()) {
 
@@ -288,21 +281,21 @@ public String getSorted(DeclaredQuery query, Sort sort, ReturnedType returnedTyp
 	 */
 	static class CachableQuery {
 
-		private final DeclaredQuery declaredQuery;
+		private final StringQuery query;
 		private final String queryString;
 		private final Sort sort;
 		private final ReturnedType returnedType;
 
-		CachableQuery(DeclaredQuery query, Sort sort, ReturnedType returnedType) {
+		CachableQuery(StringQuery query, Sort sort, ReturnedType returnedType) {
 
-			this.declaredQuery = query;
+			this.query = query;
 			this.queryString = query.getQueryString();
 			this.sort = sort;
 			this.returnedType = returnedType;
 		}
 
-		DeclaredQuery getDeclaredQuery() {
-			return declaredQuery;
+		StringQuery getDeclaredQuery() {
+			return query;
 		}
 
 		Sort getSort() {

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/query/DeclaredQuery.java

@@ -15,99 +15,45 @@
  */
 package org.springframework.data.jpa.repository.query;
 
-import java.util.List;
-
-import org.springframework.lang.Nullable;
-import org.springframework.util.ObjectUtils;
-
 /**
- * A wrapper for a String representation of a query offering information about the query.
+ * Interface defining the contract to represent a declared query.
  *
  * @author Jens Schauder
  * @author Diego Krupitza
+ * @author Mark Paluch
  * @since 2.0.3
  */
-interface DeclaredQuery {
+public interface DeclaredQuery {
 
 	/**
-	 * Creates a {@literal DeclaredQuery} from a query {@literal String}.
+	 * Creates a DeclaredQuery for a JPQL query.
 	 *
-	 * @param query might be {@literal null} or empty.
-	 * @param nativeQuery is a given query is native or not
-	 * @return a {@literal DeclaredQuery} instance even for a {@literal null} or empty argument.
+	 * @param query the JPQL query string.
+	 * @return
 	 */
-	static DeclaredQuery of(@Nullable String query, boolean nativeQuery) {
-		return ObjectUtils.isEmpty(query) ? EmptyDeclaredQuery.EMPTY_QUERY : new StringQuery(query, nativeQuery);
+	static DeclaredQuery ofJpql(String query) {
+		return new DefaultDeclaredQuery(query, false);
 	}
 
 	/**
-	 * @return whether the underlying query has at least one named parameter.
-	 */
-	boolean hasNamedParameter();
-
-	/**
-	 * Returns the query string.
-	 */
-	String getQueryString();
-
-	/**
-	 * Returns the main alias used in the query.
-	 *
-	 * @return the alias
-	 */
-	@Nullable
-	String getAlias();
-
-	/**
-	 * Returns whether the query is using a constructor expression.
+	 * Creates a DeclaredQuery for a native query.
 	 *
-	 * @since 1.10
+	 * @param query the native query string.
+	 * @return
 	 */
-	boolean hasConstructorExpression();
-
-	/**
-	 * Returns whether the query uses the default projection, i.e. returns the main alias defined for the query.
-	 */
-	boolean isDefaultProjection();
-
-	/**
-	 * Returns the {@link ParameterBinding}s registered.
-	 */
-	List<ParameterBinding> getParameterBindings();
-
-	/**
-	 * Creates a new {@literal DeclaredQuery} representing a count query, i.e. a query returning the number of rows to be
-	 * expected from the original query, either derived from the query wrapped by this instance or from the information
-	 * passed as arguments.
-	 *
-	 * @param countQueryProjection an optional return type for the query.
-	 * @return a new {@literal DeclaredQuery} instance.
-	 */
-	DeclaredQuery deriveCountQuery(@Nullable String countQueryProjection);
-
-	/**
-	 * @return whether paging is implemented in the query itself, e.g. using SpEL expressions.
-	 * @since 2.0.6
-	 */
-	default boolean usesPaging() {
-		return false;
+	static DeclaredQuery ofNative(String query) {
+		return new DefaultDeclaredQuery(query, true);
 	}
 
 	/**
-	 * Returns whether the query uses JDBC style parameters, i.e. parameters denoted by a simple ? without any index or
-	 * name.
-	 *
-	 * @return Whether the query uses JDBC style parameters.
-	 * @since 2.0.6
+	 * Returns the query string.
 	 */
-	boolean usesJdbcStyleParameters();
+	String getQueryString();
 
 	/**
 	 * Return whether the query is a native query of not.
 	 *
 	 * @return <code>true</code> if native query otherwise <code>false</code>
 	 */
-	default boolean isNativeQuery() {
-		return false;
-	}
+	boolean isNativeQuery();
 }