Query#scroll support

  + HHH-14308: Add generic type parameter to ScrollableResults

hibernate-core/src/main/java/org/hibernate/ScrollableResults.java

@@ -59,6 +59,13 @@ public interface ScrollableResults<R> extends AutoCloseable, Closeable {
 	 */
 	boolean scroll(int positions);
 
+	/**
+	 * Moves the result cursor to the specified position.
+	 *
+	 * @return {@code true} if there is a result at the new location
+	 */
+	boolean position(int position);
+
 	/**
 	 * Go to the last result.
 	 *

hibernate-core/src/main/java/org/hibernate/internal/AbstractScrollableResults.java

@@ -16,7 +16,8 @@
 import org.hibernate.sql.results.spi.RowReader;
 
 /**
- * Base implementation of the ScrollableResults interface.
+ * Base implementation of the ScrollableResults interface intended for sharing between
+ * {@link ScrollableResultsImpl} and {@link FetchingScrollableResultsImpl}
  *
  * @author Steve Ebersole
  */
@@ -91,7 +92,9 @@ public final void close() {
 			return;
 		}
 
-		getJdbcValues().finishUp( persistenceContext );
+		rowReader.finishUp( jdbcValuesSourceProcessingState );
+		jdbcValues.finishUp( persistenceContext );
+
 		getPersistenceContext().getJdbcCoordinator().afterStatementExecution();
 
 		this.closed = true;

hibernate-core/src/main/java/org/hibernate/internal/EmptyScrollableResults.java

@@ -45,6 +45,11 @@ public boolean scroll(int positions) {
 		return false;
 	}
 
+	@Override
+	public boolean position(int position) {
+		return false;
+	}
+
 	@Override
 	public boolean last() {
 		return true;

hibernate-core/src/main/java/org/hibernate/internal/FetchingScrollableResultsImpl.java

@@ -155,6 +155,11 @@ else if ( positions < 0 ) {
 		return more;
 	}
 
+	@Override
+	public boolean position(int position) {
+		throw new NotYetImplementedFor6Exception( getClass() );
+	}
+
 	@Override
 	public boolean last() {
 		throw new NotYetImplementedFor6Exception( getClass() );

hibernate-core/src/main/java/org/hibernate/internal/ScrollableResultsImpl.java

@@ -6,14 +6,11 @@
  */
 package org.hibernate.internal;
 
-import java.sql.SQLException;
-
 import org.hibernate.HibernateException;
-import org.hibernate.JDBCException;
 import org.hibernate.NotYetImplementedFor6Exception;
 import org.hibernate.engine.spi.SharedSessionContractImplementor;
-import org.hibernate.sql.results.jdbc.internal.JdbcValuesSourceProcessingStateStandardImpl;
 import org.hibernate.sql.results.internal.RowProcessingStateStandardImpl;
+import org.hibernate.sql.results.jdbc.internal.JdbcValuesSourceProcessingStateStandardImpl;
 import org.hibernate.sql.results.jdbc.spi.JdbcValues;
 import org.hibernate.sql.results.jdbc.spi.JdbcValuesSourceProcessingOptions;
 import org.hibernate.sql.results.spi.RowReader;
@@ -49,82 +46,55 @@ protected R getCurrentRow() {
 	}
 
 	@Override
-	public boolean scroll(int i) {
-		throw new NotYetImplementedFor6Exception();
-
-		// todo (6.0) : need these scrollable ResultSet "re-positioning"-style methods on the JdbcValues stuff
-
-//		try {
-//			final boolean result = getResultSet().relative( i );
-//			prepareCurrentRow( result );
-//			return result;
-//		}
-//		catch (SQLException sqle) {
-//			throw convert( sqle, "could not advance using scroll()" );
-//		}
+	public boolean next() {
+		final boolean result = getRowProcessingState().next();
+		prepareCurrentRow( result );
+		return result;
 	}
 
-	protected JDBCException convert(SQLException sqle, String message) {
-		return getPersistenceContext().getJdbcServices().getSqlExceptionHelper().convert( sqle, message );
+	@Override
+	public boolean previous() {
+		final boolean result = getRowProcessingState().previous();
+		prepareCurrentRow( result );
+		return result;
 	}
 
 	@Override
-	public boolean first() {
-		throw new NotYetImplementedFor6Exception();
-
-		// todo (6.0) : need these scrollable ResultSet "re-positioning"-style methods on the JdbcValues stuff
-
-//		try {
-//			final boolean result = getResultSet().first();
-//			prepareCurrentRow( result );
-//			return result;
-//		}
-//		catch (SQLException sqle) {
-//			throw convert( sqle, "could not advance using first()" );
-//		}
+	public boolean scroll(int i) {
+		final boolean hasResult = getRowProcessingState().scroll( i );
+		prepareCurrentRow( hasResult );
+		return hasResult;
 	}
 
 	@Override
-	public boolean last() {
-		throw new NotYetImplementedFor6Exception();
-
-		// todo (6.0) : need these scrollable ResultSet "re-positioning"-style methods on the JdbcValues stuff
-
-//		try {
-//			final boolean result = getResultSet().last();
-//			prepareCurrentRow( result );
-//			return result;
-//		}
-//		catch (SQLException sqle) {
-//			throw convert( sqle, "could not advance using last()" );
-//		}
+	public boolean position(int position) {
+		final boolean hasResult = getRowProcessingState().position( position );
+		prepareCurrentRow( hasResult );
+		return hasResult;
 	}
 
 	@Override
-	public boolean next() {
-		try {
-			final boolean result = getJdbcValues().next( getRowProcessingState() );
-			prepareCurrentRow( result );
-			return result;
-		}
-		catch (SQLException sqle) {
-			throw convert( sqle, "could not advance using next()" );
-		}
+	public boolean first() {
+		final boolean hasResult = getRowProcessingState().first();
+		prepareCurrentRow( hasResult );
+		return hasResult;
 	}
 
 	@Override
-	public boolean previous() {
-		throw new NotYetImplementedFor6Exception();
+	public boolean last() {
+		final boolean hasResult = getRowProcessingState().last();
+		prepareCurrentRow( hasResult );
+		return hasResult;
 
 		// todo (6.0) : need these scrollable ResultSet "re-positioning"-style methods on the JdbcValues stuff
 
 //		try {
-//			final boolean result = getResultSet().previous();
+//			final boolean result = getResultSet().last();
 //			prepareCurrentRow( result );
 //			return result;
 //		}
 //		catch (SQLException sqle) {
-//			throw convert( sqle, "could not advance using previous()" );
+//			throw convert( sqle, "could not advance using last()" );
 //		}
 	}
 
@@ -186,36 +156,12 @@ public boolean isLast() {
 
 	@Override
 	public int getRowNumber() throws HibernateException {
-		throw new NotYetImplementedFor6Exception();
-
-		// todo (6.0) : need these scrollable ResultSet "re-positioning"-style methods on the JdbcValues stuff
-
-//		try {
-//			return getResultSet().getRow() - 1;
-//		}
-//		catch (SQLException sqle) {
-//			throw convert( sqle, "exception calling getRow()" );
-//		}
+		return getRowProcessingState().getPosition();
 	}
 
 	@Override
 	public boolean setRowNumber(int rowNumber) throws HibernateException {
-		throw new NotYetImplementedFor6Exception();
-
-		// todo (6.0) : need these scrollable ResultSet "re-positioning"-style methods on the JdbcValues stuff
-
-//		if ( rowNumber >= 0 ) {
-//			rowNumber++;
-//		}
-//
-//		try {
-//			final boolean result = getResultSet().absolute( rowNumber );
-//			prepareCurrentRow( result );
-//			return result;
-//		}
-//		catch (SQLException sqle) {
-//			throw convert( sqle, "could not advance using absolute()" );
-//		}
+		return position( rowNumber );
 	}
 
 	private void prepareCurrentRow(boolean underlyingScrollSuccessful) {
@@ -224,15 +170,10 @@ private void prepareCurrentRow(boolean underlyingScrollSuccessful) {
 			return;
 		}
 
-		try {
-			currentRow = getRowReader().readRow(
-					getRowProcessingState(),
-					getProcessingOptions()
-			);
-		}
-		catch (SQLException e) {
-			throw convert( e, "Unable to read row as part of ScrollableResult handling" );
-		}
+		currentRow = getRowReader().readRow(
+				getRowProcessingState(),
+				getProcessingOptions()
+		);
 
 		afterScrollOperation();
 	}

hibernate-core/src/main/java/org/hibernate/jdbc/ReturningWork.java

@@ -14,6 +14,7 @@
  *
  * @author Steve Ebersole
  */
+@FunctionalInterface
 public interface ReturningWork<T> {
 	/**
 	 * Execute the discrete work encapsulated by this work instance using the supplied connection.
@@ -25,5 +26,5 @@ public interface ReturningWork<T> {
 	 * @throws SQLException Thrown during execution of the underlying JDBC interaction.
 	 * @throws org.hibernate.HibernateException Generally indicates a wrapped SQLException.
 	 */
-	public T execute(Connection connection) throws SQLException;
+	T execute(Connection connection) throws SQLException;
 }

hibernate-core/src/main/java/org/hibernate/jdbc/Work.java

@@ -14,6 +14,7 @@
  *
  * @author Steve Ebersole
  */
+@FunctionalInterface
 public interface Work {
 	/**
 	 * Execute the discrete work encapsulated by this work instance using the supplied connection.

hibernate-core/src/main/java/org/hibernate/procedure/internal/ProcedureCallImpl.java

@@ -747,7 +747,7 @@ protected List<R> doList() {
 	}
 
 	@Override
-	protected ScrollableResultsImplementor doScroll(ScrollMode scrollMode) {
+	public ScrollableResultsImplementor scroll(ScrollMode scrollMode) {
 		throw new UnsupportedOperationException( "Query#scroll is not valid for ProcedureCall/StoredProcedureQuery" );
 	}
 

hibernate-core/src/main/java/org/hibernate/query/Query.java

@@ -32,6 +32,7 @@
 import org.hibernate.ScrollMode;
 import org.hibernate.ScrollableResults;
 import org.hibernate.SharedSessionContract;
+import org.hibernate.dialect.Dialect;
 import org.hibernate.graph.GraphSemantic;
 import org.hibernate.graph.RootGraph;
 import org.hibernate.metamodel.model.domain.AllowableParameterType;
@@ -99,29 +100,23 @@ default Query<R> applyLoadGraph(RootGraph graph) {
 	}
 
 	/**
-	 * Return the query results as <tt>ScrollableResults</tt>. The
-	 * scrollability of the returned results depends upon JDBC driver
-	 * support for scrollable <tt>ResultSet</tt>s.<br>
+	 * Returns scrollable access to the query results.
 	 *
-	 * @see ScrollableResults
+	 * This form calls {@link #scroll(ScrollMode)} using {@link Dialect#defaultScrollMode()}
 	 *
-	 * @return the result iterator
+	 * @apiNote The exact behavior of this method depends somewhat
+	 * on the JDBC driver's {@link java.sql.ResultSet} scrolling support
 	 */
-	ScrollableResults scroll();
+	ScrollableResults<R> scroll();
 
 	/**
-	 * Return the query results as ScrollableResults. The scrollability of the returned results
-	 * depends upon JDBC driver support for scrollable ResultSets.
-	 *
-	 * @param scrollMode The scroll mode
-	 *
-	 * @return the result iterator
-	 *
-	 * @see ScrollableResults
-	 * @see ScrollMode
+	 * Returns scrollable access to the query results.  The capabilities of the
+	 * returned ScrollableResults depend on the specified ScrollMode.
 	 *
+	 * @apiNote The exact behavior of this method depends somewhat
+	 * on the JDBC driver's {@link java.sql.ResultSet} scrolling support
 	 */
-	ScrollableResults scroll(ScrollMode scrollMode);
+	ScrollableResults<R> scroll(ScrollMode scrollMode);
 
 	/**
 	 * Return the query results as a <tt>List</tt>. If the query contains

hibernate-core/src/main/java/org/hibernate/query/internal/AbstractProducedQuery.java

@@ -11,7 +11,6 @@
 import java.time.LocalDateTime;
 import java.time.OffsetDateTime;
 import java.time.ZonedDateTime;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Collection;
@@ -44,6 +43,7 @@
 import org.hibernate.QueryParameterException;
 import org.hibernate.ScrollMode;
 import org.hibernate.TypeMismatchException;
+import org.hibernate.dialect.Dialect;
 import org.hibernate.engine.query.spi.EntityGraphQueryHint;
 import org.hibernate.engine.spi.ExceptionConverter;
 import org.hibernate.engine.spi.QueryParameters;
@@ -1390,51 +1390,25 @@ protected void afterQuery() {
 	}
 
 	@Override
-	public ScrollableResultsImplementor scroll() {
-		return scroll( getSession().getJdbcServices().getJdbcEnvironment().getDialect().defaultScrollMode() );
+	public ScrollableResultsImplementor<R> scroll() {
+		final Dialect dialect = getSession().getJdbcServices().getJdbcEnvironment().getDialect();
+		return scroll( dialect.defaultScrollMode() );
 	}
 
 	@Override
-	public ScrollableResultsImplementor scroll(ScrollMode scrollMode) {
-		beforeQuery();
-		try {
-			return doScroll( scrollMode );
-		}
-		finally {
-			afterQuery();
-		}
-	}
-
-	protected ScrollableResultsImplementor doScroll(ScrollMode scrollMode) {
-		throw new NotYetImplementedFor6Exception( getClass() );
-
-//		if ( getMaxResults() == 0 ) {
-//			return EmptyScrollableResults.INSTANCE;
-//		}
-//
-//		final String query = getQueryParameterBindings().expandListValuedParameters( getQueryString(), getSession() );
-//		QueryParameters queryParameters = makeQueryParametersForExecution( query );
-//		queryParameters.setScrollMode( scrollMode );
-//		return getSession().scroll( query, queryParameters );
-	}
-
-	@Override
-	@SuppressWarnings("unchecked")
 	public Stream<R> stream() {
 		if (getMaxResults() == 0){
 			final Spliterator<R> spliterator = Spliterators.emptySpliterator();
 			return StreamSupport.stream( spliterator, false );
 		}
-		final ScrollableResultsImplementor scrollableResults = scroll( ScrollMode.FORWARD_ONLY );
+		final ScrollableResultsImplementor<R> scrollableResults = scroll( ScrollMode.FORWARD_ONLY );
 		final ScrollableResultsIterator<R> iterator = new ScrollableResultsIterator<>( scrollableResults );
 		final Spliterator<R> spliterator = Spliterators.spliteratorUnknownSize( iterator, Spliterator.NONNULL );
 
-		final Stream<R> stream = new StreamDecorator(
+		return new StreamDecorator<>(
 				StreamSupport.stream( spliterator, false ),
 				scrollableResults::close
 		);
-
-		return stream;
 	}
 
 	@Override