Add support for nested @ManyToOne relationships

pom.xml

@@ -5,7 +5,7 @@
 
 	<groupId>com.github.darrachequesne</groupId>
 	<artifactId>spring-data-jpa-datatables</artifactId>
-	<version>2.2</version>
+	<version>2.3-SNAPSHOT</version>
 
 	<name>Spring Data JPA for DataTables</name>
 	<description>Spring Data JPA extension to work with the great jQuery plug-in DataTables (http://datatables.net/)</description>

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

@@ -7,9 +7,11 @@
 import javax.persistence.criteria.CriteriaBuilder;
 import javax.persistence.criteria.CriteriaQuery;
 import javax.persistence.criteria.Expression;
+import javax.persistence.criteria.From;
 import javax.persistence.criteria.JoinType;
 import javax.persistence.criteria.Predicate;
 import javax.persistence.criteria.Root;
+import javax.persistence.metamodel.Attribute.PersistentAttributeType;
 
 import org.springframework.data.domain.PageRequest;
 import org.springframework.data.domain.Pageable;
@@ -193,10 +195,16 @@ private static Expression<String> getExpression(Root<?> root, String columnData)
     if (columnData.contains(ATTRIBUTE_SEPARATOR)) {
       // columnData is like "joinedEntity.attribute" so add a join clause
       String[] values = columnData.split("\\" + ATTRIBUTE_SEPARATOR);
-      if (!root.getModel().getAttribute(values[0]).isAssociation()) {
+      if (root.getModel().getAttribute(values[0])
+          .getPersistentAttributeType() == PersistentAttributeType.EMBEDDED) {
+        // with @Embedded attribute
         return root.get(values[0]).get(values[1]).as(String.class);
       }
-      return root.join(values[0], JoinType.LEFT).get(values[1]).as(String.class);
+      From<?, ?> from = root;
+      for (int i = 0; i < values.length - 1; i++) {
+        from = from.join(values[i], JoinType.LEFT);
+      }
+      return from.get(values[values.length - 1]).as(String.class);
     } else {
       // columnData is like "attribute" so nothing particular to do
       return root.get(columnData).as(String.class);

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

@@ -1,9 +1,12 @@
 package org.springframework.data.jpa.datatables;
 
 import java.sql.SQLException;
+import java.util.Properties;
 
 import javax.sql.DataSource;
 
+import org.hibernate.cfg.Environment;
+import org.hibernate.tool.hbm2ddl.MultipleLinesSqlCommandExtractor;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.jpa.datatables.repository.DataTablesRepositoryFactoryBean;
@@ -48,6 +51,13 @@ public AbstractEntityManagerFactoryBean entityManagerFactory() throws SQLExcepti
     bean.setPackagesToScan(Config.class.getPackage().getName());
     bean.setDataSource(dataSource());
 
+    Properties jpaProperties = new Properties();
+    jpaProperties.setProperty(Environment.HBM2DDL_AUTO, "create-drop");
+    jpaProperties.setProperty(Environment.HBM2DDL_IMPORT_FILES, "init.sql");
+    jpaProperties.setProperty(Environment.HBM2DDL_IMPORT_FILES_SQL_EXTRACTOR,
+        MultipleLinesSqlCommandExtractor.class.getName());
+    bean.setJpaProperties(jpaProperties);
+
     return bean;
   }
 }

src/test/java/org/springframework/data/jpa/datatables/model/Course.java

@@ -0,0 +1,47 @@
+package org.springframework.data.jpa.datatables.model;
+
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "course")
+public class Course {
+
+  @Id
+  @GeneratedValue
+  private Long id;
+
+  private String name;
+
+  @ManyToOne(fetch = FetchType.EAGER)
+  @JoinColumn(name = "course_type_id")
+  private CourseType type;
+
+  public Course() {}
+
+  public Long getId() {
+    return id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public CourseType getType() {
+    return type;
+  }
+
+  public void setType(CourseType type) {
+    this.type = type;
+  }
+
+}

src/test/java/org/springframework/data/jpa/datatables/model/CourseType.java

@@ -0,0 +1,32 @@
+package org.springframework.data.jpa.datatables.model;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "course_type")
+public class CourseType {
+
+  @Id
+  @GeneratedValue
+  private Long id;
+
+  private String name;
+
+  public CourseType() {}
+
+  public Long getId() {
+    return id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+}

src/test/java/org/springframework/data/jpa/datatables/model/Lesson.java

@@ -0,0 +1,47 @@
+package org.springframework.data.jpa.datatables.model;
+
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "lesson")
+public class Lesson {
+
+  @Id
+  @GeneratedValue
+  private Long id;
+
+  private String name;
+
+  @ManyToOne(fetch = FetchType.EAGER)
+  @JoinColumn(name = "course_id")
+  private Course course;
+
+  public Lesson() {}
+
+  public Long getId() {
+    return id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+
+  public Course getCourse() {
+    return course;
+  }
+
+  public void setCourse(Course course) {
+    this.course = course;
+  }
+
+}

src/test/java/org/springframework/data/jpa/datatables/model/LessonRepository.java

@@ -0,0 +1,7 @@
+package org.springframework.data.jpa.datatables.model;
+
+import org.springframework.data.jpa.datatables.repository.DataTablesRepository;
+
+public interface LessonRepository extends DataTablesRepository<Lesson, Long> {
+
+}

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

@@ -0,0 +1,74 @@
+package org.springframework.data.jpa.datatables.repository;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+
+import java.util.ArrayList;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.data.jpa.datatables.Config;
+import org.springframework.data.jpa.datatables.mapping.DataTablesInput;
+import org.springframework.data.jpa.datatables.mapping.DataTablesOutput;
+import org.springframework.data.jpa.datatables.model.Lesson;
+import org.springframework.data.jpa.datatables.model.LessonRepository;
+import org.springframework.data.jpa.datatables.parameter.ColumnParameter;
+import org.springframework.data.jpa.datatables.parameter.OrderParameter;
+import org.springframework.data.jpa.datatables.parameter.SearchParameter;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@ContextConfiguration(classes = Config.class)
+public class LessonRepositoryTest {
+
+  @Autowired
+  private LessonRepository lessonRepository;
+
+  @Test
+  public void testThroughTwoManyToOneRelationships() {
+    DataTablesInput input = getBasicInput();
+
+    input.getColumns().get(3).getSearch().setValue("CourseTypeA");
+    DataTablesOutput<Lesson> output = lessonRepository.findAll(input);
+    assertNotNull(output);
+    assertNull(output.getError());
+    assertEquals(5, (long) output.getRecordsFiltered());
+    assertEquals(7, (long) output.getRecordsTotal());
+
+    input.getColumns().get(2).getSearch().setValue("CourseA-2");
+    output = lessonRepository.findAll(input);
+    assertNotNull(output);
+    assertNull(output.getError());
+    assertEquals(2, (long) output.getRecordsFiltered());
+    assertEquals(7, (long) output.getRecordsTotal());
+  }
+
+  /**
+   * 
+   * @return basic input parameters
+   */
+  private static DataTablesInput getBasicInput() {
+    DataTablesInput input = new DataTablesInput();
+    input.setDraw(1);
+    input.setStart(0);
+    input.setLength(10);
+    input.setSearch(new SearchParameter("", false));
+    input.setOrder(new ArrayList<OrderParameter>());
+    input.getOrder().add(new OrderParameter(0, "asc"));
+
+    input.setColumns(new ArrayList<ColumnParameter>());
+    input.getColumns()
+        .add(new ColumnParameter("id", "", true, true, new SearchParameter("", false)));
+    input.getColumns()
+        .add(new ColumnParameter("name", "", true, true, new SearchParameter("", false)));
+    input.getColumns()
+        .add(new ColumnParameter("course.name", "", true, true, new SearchParameter("", false)));
+    input.getColumns().add(
+        new ColumnParameter("course.type.name", "", true, true, new SearchParameter("", false)));
+
+    return input;
+  }
+}

src/test/resources/init.sql

@@ -0,0 +1,19 @@
+INSERT INTO course_type (id, name) VALUES
+  (1, 'CourseTypeA'),
+  (2, 'CourseTypeB'),
+  (3, 'CourseTypeC');
+
+INSERT INTO course (id, name, course_type_id) VALUES
+  (1, 'CourseA-1', 1),
+  (2, 'CourseA-2', 1),
+  (3, 'CourseA-3', 1),
+  (4, 'CourseB-1', 2);
+
+INSERT INTO lesson (id, name, course_id) VALUES
+  (1, 'LessonA-1-a', 1),
+  (2, 'LessonA-1-b', 1),
+  (3, 'LessonA-1-c', 1),
+  (4, 'LessonA-2-a', 2),
+  (5, 'LessonA-2-b', 2),
+  (6, 'LessonB-1-a', 4),
+  (7, 'LessonB-1-b', 4);