HHH-19063 - Drop forms of SchemaNameResolver performing reflection

# Conflicts:
#	hibernate-core/src/main/java/org/hibernate/dialect/SybaseDialect.java

Author: sebersole

hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java

@@ -3668,12 +3668,7 @@ public String getCurrentSchemaCommand() {
 	 * {@link Connection}, usually {@link DefaultSchemaNameResolver}.
 	 *
 	 * @return The schema name resolver strategy
-	 *
-	 * @deprecated Since Hibernate now baselines on Java 17,
-	 * {@link Connection#getSchema()} is always available directly.
-	 * Never used internally.
 	 */
-	@Deprecated
 	public SchemaNameResolver getSchemaNameResolver() {
 		return DefaultSchemaNameResolver.INSTANCE;
 	}

hibernate-core/src/main/java/org/hibernate/dialect/SybaseDialect.java

@@ -4,14 +4,8 @@
  */
 package org.hibernate.dialect;
 
-import java.sql.DatabaseMetaData;
-import java.sql.SQLException;
-import java.sql.Types;
-import java.time.temporal.TemporalAccessor;
-import java.util.Calendar;
-import java.util.Date;
-import java.util.TimeZone;
-
+import jakarta.persistence.TemporalType;
+import org.hibernate.HibernateException;
 import org.hibernate.boot.model.FunctionContributions;
 import org.hibernate.boot.model.TypeContributions;
 import org.hibernate.dialect.function.CommonFunctionFactory;
@@ -24,20 +18,22 @@
 import org.hibernate.dialect.unique.SkipNullableUniqueDelegate;
 import org.hibernate.dialect.unique.UniqueDelegate;
 import org.hibernate.engine.jdbc.dialect.spi.DialectResolutionInfo;
+import org.hibernate.engine.jdbc.env.internal.DefaultSchemaNameResolver;
 import org.hibernate.engine.jdbc.env.spi.IdentifierCaseStrategy;
 import org.hibernate.engine.jdbc.env.spi.IdentifierHelper;
 import org.hibernate.engine.jdbc.env.spi.IdentifierHelperBuilder;
 import org.hibernate.engine.jdbc.env.spi.NameQualifierSupport;
+import org.hibernate.engine.jdbc.env.spi.SchemaNameResolver;
 import org.hibernate.engine.spi.LoadQueryInfluencers;
 import org.hibernate.engine.spi.SessionFactoryImplementor;
 import org.hibernate.procedure.internal.JTDSCallableStatementSupport;
 import org.hibernate.procedure.internal.SybaseCallableStatementSupport;
 import org.hibernate.procedure.spi.CallableStatementSupport;
+import org.hibernate.query.common.TemporalUnit;
 import org.hibernate.query.spi.QueryOptions;
 import org.hibernate.query.spi.QueryParameterBindings;
 import org.hibernate.query.sqm.CastType;
 import org.hibernate.query.sqm.IntervalType;
-import org.hibernate.query.common.TemporalUnit;
 import org.hibernate.query.sqm.internal.DomainParameterXref;
 import org.hibernate.query.sqm.sql.SqmTranslator;
 import org.hibernate.query.sqm.sql.SqmTranslatorFactory;
@@ -63,7 +59,15 @@
 import org.hibernate.type.descriptor.jdbc.TinyIntAsSmallIntJdbcType;
 import org.hibernate.type.descriptor.jdbc.spi.JdbcTypeRegistry;
 
-import jakarta.persistence.TemporalType;
+import java.sql.Connection;
+import java.sql.DatabaseMetaData;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Types;
+import java.time.temporal.TemporalAccessor;
+import java.util.Calendar;
+import java.util.Date;
+import java.util.TimeZone;
 
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsDate;
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsLocalTime;
@@ -91,6 +95,8 @@ public class SybaseDialect extends AbstractTransactSQLDialect {
 	@Deprecated(forRemoval = true)
 	protected final boolean jtdsDriver;
 
+	private final SchemaNameResolver schemaNameResolver;
+
 	public SybaseDialect() {
 		this( MINIMUM_VERSION );
 	}
@@ -99,12 +105,20 @@ public SybaseDialect(DatabaseVersion version) {
 		super(version);
 		this.driverKind = SybaseDriverKind.OTHER;
 		this.jtdsDriver = true;
+		this.schemaNameResolver = determineSchemaNameResolver( driverKind );
+	}
+
+	private static SchemaNameResolver determineSchemaNameResolver(SybaseDriverKind driverKind) {
+		return driverKind == SybaseDriverKind.JTDS
+				? new JTDSSchemaNameResolver()
+				: DefaultSchemaNameResolver.INSTANCE;
 	}
 
 	public SybaseDialect(DialectResolutionInfo info) {
 		super(info);
 		this.driverKind = SybaseDriverKind.determineKind( info );
 		this.jtdsDriver = driverKind == SybaseDriverKind.JTDS;
+		this.schemaNameResolver = determineSchemaNameResolver( driverKind );
 	}
 
 	@Override
@@ -321,6 +335,11 @@ public boolean canCreateSchema() {
 		return false;
 	}
 
+	@Override
+	public SchemaNameResolver getSchemaNameResolver() {
+		return schemaNameResolver;
+	}
+
 	@Override
 	public String getCurrentSchemaCommand() {
 		return "select user_name()";
@@ -556,4 +575,26 @@ public boolean supportsRowValueConstructorSyntaxInInList() {
 		return false;
 	}
 
+	private static class JTDSSchemaNameResolver implements SchemaNameResolver {
+		@Override
+		public String resolveSchemaName(Connection connection, Dialect dialect) throws SQLException {
+			//noinspection deprecation
+			final String command = dialect.getCurrentSchemaCommand();
+			if ( command == null ) {
+				throw new HibernateException(
+						"Use of DefaultSchemaNameResolver requires Dialect to provide the " +
+						"proper SQL statement/command but provided Dialect [" +
+						dialect.getClass().getName() + "] did not return anything " +
+						"from Dialect#getCurrentSchemaCommand"
+				);
+			}
+
+			try (final java.sql.Statement statement = connection.createStatement()) {
+				try (ResultSet resultSet = statement.executeQuery( command )) {
+					return resultSet.next() ? resultSet.getString( 1 ) : null;
+				}
+			}
+		}
+	}
+
 }

hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/DefaultSchemaNameResolver.java

@@ -11,14 +11,11 @@
 import java.sql.SQLException;
 
 /**
- * Default implementation of {@link SchemaNameResolver}.
- *
- * @deprecated Since Hibernate now baselines on Java 17,
- * {@link Connection#getSchema()} is always available directly.
+ * Default implementation of {@link SchemaNameResolver}
+ * using {@link Connection#getSchema()}.
  *
  * @author Steve Ebersole
  */
-@Deprecated
 public class DefaultSchemaNameResolver implements SchemaNameResolver {
 	public static final DefaultSchemaNameResolver INSTANCE = new DefaultSchemaNameResolver();
 

hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/internal/JdbcEnvironmentImpl.java

@@ -8,6 +8,7 @@
 import java.sql.SQLException;
 
 import org.hibernate.boot.model.naming.Identifier;
+import org.hibernate.boot.registry.selector.spi.StrategySelector;
 import org.hibernate.cfg.AvailableSettings;
 import org.hibernate.dialect.Dialect;
 import org.hibernate.engine.config.spi.ConfigurationService;
@@ -21,6 +22,7 @@
 import org.hibernate.engine.jdbc.env.spi.LobCreatorBuilder;
 import org.hibernate.engine.jdbc.env.spi.NameQualifierSupport;
 import org.hibernate.engine.jdbc.env.spi.QualifiedObjectNameFormatter;
+import org.hibernate.engine.jdbc.env.spi.SchemaNameResolver;
 import org.hibernate.engine.jdbc.spi.SqlExceptionHelper;
 import org.hibernate.exception.internal.SQLExceptionTypeDelegate;
 import org.hibernate.exception.internal.SQLStateConversionDelegate;
@@ -292,7 +294,7 @@ public JdbcEnvironmentImpl(
 		this.extractedMetaDataSupport =
 				new ExtractedDatabaseMetaDataImpl.Builder( this, true, jdbcConnectionAccess )
 						.apply( databaseMetaData )
-						.setConnectionSchemaName( determineCurrentSchemaName( databaseMetaData ) )
+						.setConnectionSchemaName( determineCurrentSchemaName( databaseMetaData, serviceRegistry, dialect ) )
 						.setSupportsNamedParameters( dialect.supportsNamedParameters( databaseMetaData ) )
 						.build();
 
@@ -328,16 +330,37 @@ private static IdentifierHelper identifierHelper(
 		return identifierHelperBuilder.build();
 	}
 
-	private String determineCurrentSchemaName(DatabaseMetaData databaseMetaData) {
+	public static final String SCHEMA_NAME_RESOLVER = "hibernate.schema_name_resolver";
+
+	/**
+	 * @deprecated Only needed any longer for Sybase + jTDS driver combo
+	 */
+	@Deprecated
+	private String determineCurrentSchemaName(
+			DatabaseMetaData databaseMetaData,
+			ServiceRegistry serviceRegistry,
+			Dialect dialect) {
+		final SchemaNameResolver resolver = getSchemaNameResolver( serviceRegistry, dialect );
 		try {
-			return databaseMetaData.getConnection().getSchema();
+			return resolver.resolveSchemaName( databaseMetaData.getConnection(), dialect );
 		}
 		catch (Exception e) {
 			log.debug( "Unable to resolve connection default schema", e );
 			return null;
 		}
 	}
 
+	private static SchemaNameResolver getSchemaNameResolver(ServiceRegistry serviceRegistry, Dialect dialect) {
+		final Object setting =
+				serviceRegistry.requireService( ConfigurationService.class )
+						.getSettings().get( SCHEMA_NAME_RESOLVER );
+		return setting == null
+				? dialect.getSchemaNameResolver()
+				: serviceRegistry.requireService( StrategySelector.class )
+						.resolveDefaultableStrategy( SchemaNameResolver.class, setting,
+								dialect.getSchemaNameResolver() );
+	}
+
 	private static SqlExceptionHelper buildSqlExceptionHelper(Dialect dialect, boolean logWarnings) {
 		final SQLExceptionConversionDelegate dialectDelegate = dialect.buildSQLExceptionConversionDelegate();
 		final SQLExceptionConversionDelegate[] delegates = dialectDelegate == null

hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/JdbcEnvironment.java

@@ -48,6 +48,8 @@ public interface JdbcEnvironment extends Service {
 	 * {@link java.sql.Connection#getSchema()} or
 	 * {@value org.hibernate.cfg.AvailableSettings#DEFAULT_SCHEMA}.
 	 *
+	 * @see org.hibernate.engine.jdbc.spi.SchemaNameResolver
+	 *
 	 * @return The current schema
 	 */
 	Identifier getCurrentSchema();

hibernate-core/src/main/java/org/hibernate/engine/jdbc/env/spi/SchemaNameResolver.java

@@ -12,12 +12,12 @@
 /**
  * Contract for resolving the schema of a {@link Connection}.
  *
- * @deprecated Since Hibernate now baselines on Java 17,
- * {@link Connection#getSchema()} is always available directly.
+ * @implNote Since Hibernate baselines on Java 17+, this should no longer be
+ * needed as we should be able to rely on {@link Connection#getSchema()}.
+ * However, some drivers still do not implement this or implement it "properly".
  *
  * @author Steve Ebersole
  */
-@Deprecated
 public interface SchemaNameResolver {
 	/**
 	 * Given a JDBC {@link Connection}, resolve the name of the schema (if one) to which it connects.

hibernate-core/src/main/java/org/hibernate/engine/jdbc/spi/SchemaNameResolver.java

@@ -9,6 +9,12 @@
 /**
  * Contract for resolving the schema of a {@link Connection}.
  *
+ * @apiNote Exists mainly for historical reasons when Hibernate
+ * baselines on Java versions before 8 when {@linkplain Connection#getSchema()}
+ * was introduced.  We still use it at the moment because some drivers do not
+ * implement it (jTDS) and/or some databases do not support schemas and
+ * their drivers don't DoTheRightThing.
+ *
  * @author Steve Ebersole
  */
 public interface SchemaNameResolver {