Merge pull request darrachequesne#16 from darrachequesne/patch-3

Ensure related entities are eagerly loaded

Author: darrachequesne

pom.xml

@@ -64,7 +64,7 @@
 
 <spring.version>4.2.0.RELEASE</spring.version>
 <spring.data.jpa.version>1.8.2.RELEASE</spring.data.jpa.version>
-<hibernate.version>4.3.10.Final</hibernate.version>
+<hibernate.version>4.3.11.Final</hibernate.version>
 <hibernate.validator.version>5.2.0.Final</hibernate.validator.version>
 <jackson.version>2.6.0</jackson.version>
 <javax.el.api.version>2.2.5</javax.el.api.version>

src/main/java/org/springframework/data/jpa/datatables/repository/DataTablesUtils.java

@@ -7,6 +7,7 @@
 import javax.persistence.criteria.CriteriaBuilder;
 import javax.persistence.criteria.CriteriaQuery;
 import javax.persistence.criteria.Expression;
+import javax.persistence.criteria.Fetch;
 import javax.persistence.criteria.From;
 import javax.persistence.criteria.JoinType;
 import javax.persistence.criteria.Predicate;
@@ -102,6 +103,29 @@ public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query,
  }
  predicate = criteriaBuilder.and(predicate, matchOneColumnPredicate);
  }
+ // findAll method does a count query first, and then query for the actual data. Yet in the
+ // count query, adding a JOIN FETCH results in the following error 'query specified join
+ // fetching, but the owner of the fetched association was not present in the select list'
+ // see https://jira.spring.io/browse/DATAJPA-105
+ boolean isCountQuery = query.getResultType() == Long.class;
+ if (isCountQuery) {
+ return predicate;
+ }
+ // add JOIN FETCH when necessary
+ for (ColumnParameter column : input.getColumns()) {
+ if (!column.getSearchable() || !column.getData().contains(ATTRIBUTE_SEPARATOR)) {
+ continue;
+ }
+ String[] values = column.getData().split("\\" + ATTRIBUTE_SEPARATOR);
+ if (root.getModel().getAttribute(values[0])
+ .getPersistentAttributeType() == PersistentAttributeType.EMBEDDED) {
+ continue;
+ }
+ Fetch<?, ?> fetch = null;
+ for (int i = 0; i < values.length - 1; i++) {
+ fetch = (fetch == null ? root : fetch).fetch(values[i], JoinType.LEFT);
+ }
+ }
  return predicate;
  }
 

src/test/java/org/springframework/data/jpa/datatables/Config.java

@@ -5,7 +5,9 @@
 
 import javax.sql.DataSource;
 
+import org.hibernate.SessionFactory;
 import org.hibernate.cfg.Environment;
+import org.hibernate.jpa.HibernateEntityManagerFactory;
 import org.hibernate.tool.hbm2ddl.MultipleLinesSqlCommandExtractor;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -60,4 +62,10 @@ public AbstractEntityManagerFactoryBean entityManagerFactory() throws SQLExcepti
 
  return bean;
  }
+
+ @Bean
+ public SessionFactory sessionFactory() throws SQLException {
+ return ((HibernateEntityManagerFactory) entityManagerFactory().getObject()).getSessionFactory();
+ }
+
 }

src/test/java/org/springframework/data/jpa/datatables/repository/LessonRepositoryTest.java

@@ -4,6 +4,8 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 
+import org.hibernate.SessionFactory;
+import org.hibernate.stat.Statistics;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -22,6 +24,9 @@ public class LessonRepositoryTest {
  @Autowired
  private LessonRepository lessonRepository;
 
+ @Autowired
+ private SessionFactory sessionFactory;
+
  @Test
  public void testThroughTwoManyToOneRelationships() {
  DataTablesInput input = getBasicInput();
@@ -41,6 +46,22 @@ public void testThroughTwoManyToOneRelationships() {
  assertEquals(7, output.getRecordsTotal());
  }
 
+ @Test
+ public void testEagerLoading() {
+ DataTablesInput input = getBasicInput();
+
+ Statistics statistics = sessionFactory.getStatistics();
+ statistics.setStatisticsEnabled(true);
+ DataTablesOutput<Lesson> output = lessonRepository.findAll(input);
+ assertEquals("CourseTypeA", output.getData().get(0).getCourse().getType().getName());
+ statistics.setStatisticsEnabled(false);
+
+ // there should be only three executed queries : count unfiltered, count filtered and actual
+ // data (with FETCH JOIN)
+ assertEquals(3, statistics.getPrepareStatementCount());
+ assertEquals(7 + 3 + 2, statistics.getEntityLoadCount());
+ }
+
  /**
  * 
  * @return basic input parameters

src/test/resources/log4j.properties

@@ -4,4 +4,5 @@ log4j.appender.console.layout=org.apache.log4j.PatternLayout
 log4j.appender.console.layout.ConversionPattern=%d{ABSOLUTE} %5p %40.40c:%4L - %m%n
 log4j.appender.console=org.apache.log4j.ConsoleAppender
 
-log4j.logger.org.springframework=INFO
+log4j.logger.org.springframework=INFO
+log4j.logger.org.hibernate.SQL=DEBUG