HHH-10563 : Significant String use/duplication associated with subselect fetch

hibernate-core/src/main/java/org/hibernate/engine/spi/SubselectFetch.java

@@ -34,8 +34,59 @@ public class SubselectFetch {
 	private final QueryParameters queryParameters;
 	private final Map namedParameterLocMap;
 
+	/**
+	 * Construct a SubselectFetch instance. The subselect fetch query fragment is generated by
+	 * {@link #createSubselectFetchQueryFragment}.
+	 *
+	 * If the same value for {@code queryParameters} is to be used when constructing multiple
+	 * SubselectFetch objects, then it is preferable to generate the subselect fetch query
+	 * fragment using {@link #createSubselectFetchQueryFragment}, and pass the result as an
+	 * argument to constructor {@link #SubselectFetch(String, String, Loadable, QueryParameters, Set, Map)}.
+	 *
+	 * @param alias - the table alias used in the subselect fetch query fragment
+	 * (to be generated by {@link #createSubselectFetchQueryFragment(QueryParameters)} that
+	 * corresponds to {@code loadable};
+	 * @param loadable - the {@link Loadable} for the associated entities to be subselect fetched;
+	 * @param queryParameters - the query parameters;
+	 * @param resultingEntityKeys - the {@link EntityKey} objects for the entities to be subselect fetched;
+	 * @param namedParameterLocMap - mapping from named parameter to the parameter index located in the
+	 * subselect fetch query fragment.
+	 *
+	 * @see #SubselectFetch(String, String, Loadable, QueryParameters, Set, Map)
+	 */
 	public SubselectFetch(
-			//final String queryString,
+			final String alias,
+			final Loadable loadable,
+			final QueryParameters queryParameters,
+			final Set resultingEntityKeys,
+			final Map namedParameterLocMap) {
+		this(
+				createSubselectFetchQueryFragment( queryParameters ),
+				alias,
+				loadable,
+				queryParameters,
+				resultingEntityKeys,
+				namedParameterLocMap
+		);
+	}
+
+	/**
+	 * Construct a SubselectFetch instance using the provided subselect fetch query fragment,
+	 * {@code subselectFetchQueryFragment}. It is assumed that {@code subselectFetchQueryFragment}
+	 * is the result of calling {@link #createSubselectFetchQueryFragment} with the same value
+	 * provided for {@code queryParameters}.
+	 *
+	 * @param subselectFetchQueryFragment - the subselect fetch query fragment;
+	 * @param alias - the table alias used in {@code subselectFetchQueryFragment} that
+	 * corresponds to {@code loadable};
+	 * @param loadable - the {@link Loadable} for the associated entities to be subselect fetched;
+	 * @param queryParameters - the query parameters;
+	 * @param resultingEntityKeys - the {@link EntityKey} objects for the entities to be subselect fetched;
+	 * @param namedParameterLocMap - mapping from named parameter to the parameter index located in the
+	 * subselect fetch query fragment.
+	 */
+	public SubselectFetch(
+			final String subselectFetchQueryFragment,
 			final String alias,
 			final Loadable loadable,
 			final QueryParameters queryParameters,
@@ -47,16 +98,28 @@ public SubselectFetch(
 		this.loadable = loadable;
 		this.alias = alias;
 
+		this.queryString = subselectFetchQueryFragment;
+	}
+
+	/**
+	 * Create the subselect fetch query fragment for the provided {@link QueryParameters}
+	 * with SELECT and ORDER BY clauses removed.
+	 *
+	 * @param queryParameters -the query parameters.
+	 * @return the subselect fetch query fragment.
+	 */
+	public static String createSubselectFetchQueryFragment(QueryParameters queryParameters) {
 		//TODO: ugly here:
 		final String queryString = queryParameters.getFilteredSQL();
 		final int fromIndex = getFromIndex( queryString );
 		final int orderByIndex = queryString.lastIndexOf( "order by" );
-		this.queryString = orderByIndex > 0
+		final String subselectQueryFragment =  orderByIndex > 0
 				? queryString.substring( fromIndex, orderByIndex )
 				: queryString.substring( fromIndex );
 		if ( LOG.isTraceEnabled() ) {
-			LOG.tracef( "Generated SubselectFetch query: %s", queryString );
+			LOG.tracef( "SubselectFetch query fragment: %s", subselectQueryFragment );
 		}
+		return subselectQueryFragment;
 	}
 
 	private static int getFromIndex(String queryString) {

hibernate-core/src/main/java/org/hibernate/loader/Loader.java

@@ -1036,6 +1036,7 @@ private void createSubselects(List keys, QueryParameters queryParameters, Sessio
 
 			final Loadable[] loadables = getEntityPersisters();
 			final String[] aliases = getAliases();
+			final String subselectQueryString = SubselectFetch.createSubselectFetchQueryFragment( queryParameters );
 			for ( Object key : keys ) {
 				final EntityKey[] rowKeys = (EntityKey[]) key;
 				for ( int i = 0; i < rowKeys.length; i++ ) {
@@ -1043,7 +1044,7 @@ private void createSubselects(List keys, QueryParameters queryParameters, Sessio
 					if ( rowKeys[i] != null && loadables[i].hasSubselectLoadableCollections() ) {
 
 						SubselectFetch subselectFetch = new SubselectFetch(
-								//getSQLString(),
+								subselectQueryString,
 								aliases[i],
 								loadables[i],
 								queryParameters,

hibernate-core/src/main/java/org/hibernate/loader/plan/exec/process/internal/ResultSetProcessingContextImpl.java

@@ -322,13 +322,14 @@ private void createSubselects() {
 		final Map<String, int[]> namedParameterLocMap =
 				ResultSetProcessorHelper.buildNamedParameterLocMap( queryParameters, namedParameterContext );
 
+		final String subselectQueryString = SubselectFetch.createSubselectFetchQueryFragment( queryParameters );
 		for ( Map.Entry<EntityPersister, Set<EntityKey>> entry : subselectLoadableEntityKeyMap.entrySet() ) {
 			if ( ! entry.getKey().hasSubselectLoadableCollections() ) {
 				continue;
 			}
 
 			SubselectFetch subselectFetch = new SubselectFetch(
-					//getSQLString(),
+					subselectQueryString,
 					null, // aliases[i],
 					(Loadable) entry.getKey(),
 					queryParameters,
@@ -339,7 +340,6 @@ private void createSubselects() {
 			for ( EntityKey key : entry.getValue() ) {
 				session.getPersistenceContext().getBatchFetchQueue().addSubselect( key, subselectFetch );
 			}
-
 		}
 	}