BAEL - 2823

persistence-modules/spring-data-jpa-2/src/main/java/com/baeldung/entitygraph/model/Characteristic.java

@@ -0,0 +1,43 @@
+package com.baeldung.entitygraph.model;
+
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+
+@Entity
+public class Characteristic {
+
+    @Id
+    private Long id;
+    private String type;
+    
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn
+    private Item item;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public Item getItem() {
+        return item;
+    }
+
+    public void setItem(Item item) {
+        this.item = item;
+    }
+}

persistence-modules/spring-data-jpa-2/src/main/java/com/baeldung/entitygraph/model/Item.java

@@ -0,0 +1,48 @@
+package com.baeldung.entitygraph.model;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.NamedAttributeNode;
+import javax.persistence.NamedEntityGraph;
+import javax.persistence.OneToMany;
+
+@Entity
+@NamedEntityGraph(name = "Item.characteristics",
+    attributeNodes = @NamedAttributeNode("characteristics")
+)
+public class Item {
+
+    @Id
+    private Long id;
+    private String name;
+    
+    @OneToMany(mappedBy = "item")
+    private List<Characteristic> characteristics = new ArrayList<>();
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public List<Characteristic> getCharacteristics() {
+        return characteristics;
+    }
+
+    public void setCharacteristics(List<Characteristic> characteristics) {
+        this.characteristics = characteristics;
+    }
+}

persistence-modules/spring-data-jpa-2/src/main/java/com/baeldung/entitygraph/repository/CharacteristicsRepository.java

@@ -0,0 +1,13 @@
+package com.baeldung.entitygraph.repository;
+
+import org.springframework.data.jpa.repository.EntityGraph;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import com.baeldung.entitygraph.model.Characteristic;
+
+public interface CharacteristicsRepository extends JpaRepository<Characteristic , Long> {
+    
+    @EntityGraph(attributePaths = {"item"})
+    Characteristic findByType(String type);    
+    
+}

persistence-modules/spring-data-jpa-2/src/main/java/com/baeldung/entitygraph/repository/ItemRepository.java

@@ -0,0 +1,13 @@
+package com.baeldung.entitygraph.repository;
+
+import org.springframework.data.jpa.repository.EntityGraph;
+import org.springframework.data.jpa.repository.EntityGraph.EntityGraphType;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import com.baeldung.entitygraph.model.Item;
+
+public interface ItemRepository extends JpaRepository<Item, Long> {
+
+    @EntityGraph(value = "Item.characteristics", type = EntityGraphType.FETCH)
+    Item findByName(String name);
+}

persistence-modules/spring-data-jpa-2/src/test/java/com/baeldung/entitygraph/EntityGraphIntegrationTest.java

@@ -0,0 +1,39 @@
+package com.baeldung.entitygraph;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.test.context.jdbc.Sql;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import com.baeldung.entitygraph.model.Characteristic;
+import com.baeldung.entitygraph.model.Item;
+import com.baeldung.entitygraph.repository.CharacteristicsRepository;
+import com.baeldung.entitygraph.repository.ItemRepository;
+
+@DataJpaTest
+@RunWith(SpringRunner.class)
+@Sql(scripts = "/entitygraph-data.sql")
+public class EntityGraphIntegrationTest {
+   
+    @Autowired
+    private ItemRepository itemRepo;
+    
+    @Autowired
+    private CharacteristicsRepository characteristicsRepo;
+    
+    @Test
+    public void givenEntityGraph_whenCalled_shouldRetrunDefinedFields() {
+        Item item = itemRepo.findByName("Table");
+        assertThat(item.getId()).isEqualTo(1L);
+    }
+    
+    @Test
+    public void givenAdhocEntityGraph_whenCalled_shouldRetrunDefinedFields() {
+        Characteristic characteristic = characteristicsRepo.findByType("Rigid");
+        assertThat(characteristic.getId()).isEqualTo(1L);
+    }
+}

persistence-modules/spring-data-jpa-2/src/test/resources/entitygraph-data.sql

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+INSERT INTO Item(id,name) VALUES (1,'Table');
+INSERT INTO Item(id,name) VALUES (2,'Bottle');
+
+INSERT INTO Characteristic(id,item_id, type) VALUES (1,1,'Rigid');
+INSERT INTO Characteristic(id,item_id,type) VALUES (2,1,'Big');
+INSERT INTO Characteristic(id,item_id,type) VALUES (3,2,'Fragile');
+INSERT INTO Characteristic(id,item_id,type) VALUES (4,2,'Small');