enable query hints for SQL Server 2012

hibernate-core/src/main/java/org/hibernate/dialect/SQLServer2012Dialect.java

@@ -23,7 +23,10 @@
  */
 package org.hibernate.dialect;
 
+import java.util.ArrayList;
+import java.util.List;
 
+import org.hibernate.internal.util.StringHelper;
 /**
  * Microsoft SQL Server 2012 Dialect
  *
@@ -65,4 +68,29 @@ public class SQLServer2012Dialect extends SQLServer2008Dialect {
 	public String getQuerySequencesString() {
 		return "select name from sys.sequences";
 	}
+	
+	@Override
+	public String getQueryHintString(String sql, List<String> hints) {
+		final String hint = StringHelper.join(", ", hints.iterator());
+
+		if (StringHelper.isEmpty(hint)) {
+			return sql;
+		}
+
+		final StringBuilder buffer = new StringBuilder(sql.length()
+				+ hint.length() + 12);
+		final int pos = sql.indexOf(";");
+		if (pos > -1) {
+			buffer.append(sql.substring(0, pos));
+		} else {
+			buffer.append(sql);
+		}
+		buffer.append(" OPTION (").append(hint).append(")");
+		if (pos > -1) {
+			buffer.append(";");
+		}
+		sql = buffer.toString();
+
+		return sql;
+	}
 }

hibernate-core/src/test/java/org/hibernate/test/queryhint/QueryHintSQLServer2012Test.java

@@ -0,0 +1,177 @@
+
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ * 
+ * JBoss, Home of Professional Open Source
+ * Copyright 2013 Red Hat Inc. and/or its affiliates and other contributors
+ * as indicated by the @authors tag. All rights reserved.
+ * See the copyright.txt in the distribution for a
+ * full listing of individual contributors.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License, v. 2.1.
+ * This program is distributed in the hope that it will be useful, but WITHOUT A
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ * You should have received a copy of the GNU Lesser General Public License,
+ * v.2.1 along with this distribution; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA  02110-1301, USA.
+ */
+package org.hibernate.test.queryhint;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import java.util.List;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.ManyToOne;
+
+import org.hibernate.Criteria;
+import org.hibernate.Query;
+import org.hibernate.Session;
+import org.hibernate.cfg.AvailableSettings;
+import org.hibernate.cfg.Configuration;
+import org.hibernate.criterion.Restrictions;
+import org.hibernate.dialect.SQLServer2012Dialect;
+import org.hibernate.testing.RequiresDialect;
+import org.hibernate.testing.junit4.BaseCoreFunctionalTestCase;
+import org.junit.Test;
+
+/**
+ * @author Brett Meyer
+ */
+
+@RequiresDialect(SQLServer2012Dialect.class)
+public class QueryHintSQLServer2012Test extends BaseCoreFunctionalTestCase {
+
+	@Override
+	protected Class<?>[] getAnnotatedClasses() {
+		return new Class<?>[] { Employee.class, Department.class };
+	}
+
+	@Override
+	protected void configure(Configuration configuration) {
+		configuration.setProperty( AvailableSettings.DIALECT, QueryHintTestSQLServer2012Dialect.class.getName() );
+		configuration.setProperty( AvailableSettings.USE_SQL_COMMENTS, "true" );
+	}
+
+	@Test
+	public void testQueryHint() {
+		Department department = new Department();
+		department.name = "Sales";
+		Employee employee1 = new Employee();
+		employee1.department = department;
+		Employee employee2 = new Employee();
+		employee2.department = department;
+
+		Session s = openSession();
+		s.getTransaction().begin();
+		s.persist( department );
+		s.persist( employee1 );
+		s.persist( employee2 );
+		s.getTransaction().commit();
+		s.clear();
+
+		// test Query w/ a simple SQLServer2012 optimizer hint
+		s.getTransaction().begin();
+		Query query = s.createQuery( "FROM QueryHintTest$Employee e WHERE e.department.name = :departmentName" ).addQueryHint( "MAXDOP 2" )
+				.setParameter( "departmentName", "Sales" );
+		List results = query.list();
+		s.getTransaction().commit();
+		s.clear();
+
+		assertEquals( results.size(), 2 );
+		assertTrue( QueryHintTestSQLServer2012Dialect.getProcessedSql().contains( "OPTION (MAXDOP 2)" ) );
+
+		QueryHintTestSQLServer2012Dialect.resetProcessedSql();
+
+		// test multiple hints
+		s.getTransaction().begin();
+		query = s.createQuery( "FROM QueryHintTest$Employee e WHERE e.department.name = :departmentName" ).addQueryHint( "MAXDOP 2" )
+				.addQueryHint( "USE_CONCAT" ).setParameter( "departmentName", "Sales" );
+		results = query.list();
+		s.getTransaction().commit();
+		s.clear();
+
+		assertEquals( results.size(), 2 );
+		assertTrue( QueryHintTestSQLServer2012Dialect.getProcessedSql().contains( "OPTION (MAXDOP 2)" ) );
+
+		QueryHintTestSQLServer2012Dialect.resetProcessedSql();
+
+		// ensure the insertion logic can handle a comment appended to the front
+		s.getTransaction().begin();
+		query = s.createQuery( "FROM QueryHintTest$Employee e WHERE e.department.name = :departmentName" ).setComment( "this is a test" )
+				.addQueryHint( "MAXDOP 2" ).setParameter( "departmentName", "Sales" );
+		results = query.list();
+		s.getTransaction().commit();
+		s.clear();
+
+		assertEquals( results.size(), 2 );
+		assertTrue( QueryHintTestSQLServer2012Dialect.getProcessedSql().contains( "OPTION (MAXDOP 2)" ) );
+
+		QueryHintTestSQLServer2012Dialect.resetProcessedSql();
+
+		// test Criteria
+		s.getTransaction().begin();
+		Criteria criteria = s.createCriteria( Employee.class ).addQueryHint( "MAXDOP 2" ).createCriteria( "department" )
+				.add( Restrictions.eq( "name", "Sales" ) );
+		results = criteria.list();
+		s.getTransaction().commit();
+		s.close();
+
+		assertEquals( results.size(), 2 );
+		assertTrue( QueryHintTestSQLServer2012Dialect.getProcessedSql().contains( "OPTION (MAXDOP 2)" ) );
+		assertEquals( false, true );
+	}
+
+	/**
+	 * Since the query hint is added to the SQL during Loader's executeQueryStatement -> preprocessSQL, rather than
+	 * early on during the QueryTranslator or QueryLoader initialization, there's not an easy way to check the full SQL
+	 * after completely processing it. Instead, use this ridiculous hack to ensure Loader actually calls Dialect. TODO:
+	 * This is terrible. Better ideas?
+	 */
+	public static class QueryHintTestSQLServer2012Dialect extends SQLServer2012Dialect {
+
+		private static String processedSql;
+
+		@Override
+		public String getQueryHintString(String sql, List<String> hints) {
+			processedSql = super.getQueryHintString( sql, hints );
+			return processedSql;
+		}
+
+		public static String getProcessedSql() {
+			return processedSql;
+		}
+
+		public static void resetProcessedSql() {
+			processedSql = "";
+		}
+	}
+
+	@Entity
+	public static class Employee {
+
+		@Id
+		@GeneratedValue
+		public long id;
+
+		@ManyToOne
+		public Department department;
+	}
+
+	@Entity
+	public static class Department {
+
+		@Id
+		@GeneratedValue
+		public long id;
+
+		public String name;
+	}
+}