DATAJPA-54 - Added forCounting() flag to @QueryHints.

The flag defaults to true and allows disabling of QueryHints being applied to the count query additionally triggered for pagination.

src/docbkx/reference/jpa.xml

@@ -18,8 +18,8 @@
       <para>The JPA module of Spring Data contains a custom namespace that
       allows defining repository beans. It also contains certain features and
       element attributes that are special to JPA. Generally the JPA
-      repositories can be set up using the <code>repositories</code> element:
-      </para>
+      repositories can be set up using the <code>repositories</code>
+      element:</para>
 
       <example>
         <title>Setting up JPA repositories using the namespace</title>
@@ -444,6 +444,33 @@ int setFixedFirstnameFor(String firstname, String lastname);</programlisting>
       <code>clearAutomatically</code> attribute to
       <literal>false</literal>;</para>
     </section>
+
+    <section id="jpa.query-hints">
+      <title>Applying query hints</title>
+
+      <para>To apply JPA <interfacename>QueryHint</interfacename>s to the
+      queries declared in your repository interface you can use the
+      <interfacename>QueryHints</interfacename> annotation. It takes an array
+      of JPA <interfacename>QueryHint</interfacename> annotations plus a
+      boolean flag to potentially disable the hints applied to the addtional
+      count query triggered when applying pagination.</para>
+
+      <example>
+        <title>Using QueryHints with a repository method</title>
+
+        <programlisting language="java">public interface UserRepository extends Repository&lt;User, Long&gt; {
+
+  @QueryHints(value = { @QueryHint(name = "name", value = "value")}, 
+              forCounting = false)
+  Page&lt;User&gt; findByLastname(String lastname, Pageable pageable);
+}</programlisting>
+
+        <para>The just shown declaration would apply the configured
+        <interfacename>QueryHint</interfacename> for that actually query but
+        omit applying it to the count query triggered to calculate the total
+        number of pages.</para>
+      </example>
+    </section>
   </section>
 
   <section id="specifications">

src/main/java/org/springframework/data/jpa/repository/QueryHints.java

@@ -34,5 +34,18 @@ import javax.persistence.QueryHint;
 @Retention(RetentionPolicy.RUNTIME)
 public @interface QueryHints {
 
+	/**
+	 * The {@link QueryHint}s to apply when the query will be executed.
+	 * 
+	 * @return
+	 */
 	QueryHint[] value() default {};
+
+	/**
+	 * Defines whether the configured {@link QueryHint}s shall be applied for count queries during pagination as well.
+	 * Defaults to {@literal true}.
+	 * 
+	 * @return
+	 */
+	boolean forCounting() default true;
 }

src/main/java/org/springframework/data/jpa/repository/query/AbstractJpaQuery.java

@@ -131,7 +131,8 @@ public abstract class AbstractJpaQuery implements RepositoryQuery {
 	}
 
 	protected TypedQuery<Long> createCountQuery(Object[] values) {
-		return applyHints(doCreateCountQuery(values), method);
+		TypedQuery<Long> countQuery = doCreateCountQuery(values);
+		return method.applyHintsToCountQuery() ? applyHints(countQuery, method) : countQuery;
 	}
 
 	/**

src/main/java/org/springframework/data/jpa/repository/query/JpaQueryMethod.java

@@ -93,6 +93,18 @@ public class JpaQueryMethod extends QueryMethod {
 		return result;
 	}
 
+	/**
+	 * Returns whether the potentially configured {@link QueryHint}s shall be applied when triggering the count query for
+	 * pagination.
+	 * 
+	 * @return
+	 */
+	boolean applyHintsToCountQuery() {
+
+		QueryHints hints = getAnnotation(method, QueryHints.class);
+		return hints != null ? hints.forCounting() : false;
+	}
+
 	/**
 	 * Returns the {@link QueryExtractor}.
 	 * 

src/test/java/org/springframework/data/jpa/repository/query/AbstractJpaQueryTests.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2008-2011 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.springframework.data.jpa.repository.query;
 
 import static org.mockito.Mockito.*;
@@ -65,10 +80,34 @@ public class AbstractJpaQueryTests {
 		verify(result).setHint("foo", "bar");
 	}
 
+	/**
+	 * @see DATAJPA-54
+	 * @throws Exception
+	 */
+	@Test
+	public void skipsHintsForCountQueryIfConfigured() throws Exception {
+
+		Method method = SampleRepository.class.getMethod("findByFirstname", String.class);
+		QueryExtractor provider = PersistenceProvider.fromEntityManager(em);
+		JpaQueryMethod queryMethod = new JpaQueryMethod(method, new DefaultRepositoryMetadata(SampleRepository.class),
+				provider);
+
+		AbstractJpaQuery jpaQuery = new DummyJpaQuery(queryMethod, em);
+
+		Query result = jpaQuery.createQuery(new Object[] { "Dave" });
+		verify(result).setHint("bar", "foo");
+
+		result = jpaQuery.createCountQuery(new Object[] { "Dave" });
+		verify(result, never()).setHint("bar", "foo");
+	}
+
 	interface SampleRepository extends Repository<User, Integer> {
 
 		@QueryHints({ @QueryHint(name = "foo", value = "bar") })
 		List<User> findByLastname(String lastname);
+
+		@QueryHints(value = { @QueryHint(name = "bar", value = "foo") }, forCounting = false)
+		List<User> findByFirstname(String firstname);
 	}
 
 	class DummyJpaQuery extends AbstractJpaQuery {