Feat: spring-data with lazy load entities

pom.xml

@@ -19,5 +19,6 @@
         <module>spring-annotation</module>
         <module>spring-testing</module>
         <module>spring-cache</module>
+        <module>spring-data</module>
     </modules>
 </project>

spring-data/.gitignore

@@ -0,0 +1,33 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

spring-data/pom.xml

@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.4.3</version>
+		<relativePath/> <!-- lookup parent from repository -->
+	</parent>
+	<groupId>com.spring</groupId>
+	<artifactId>spring-data</artifactId>
+	<version>1.0.0</version>
+	<name>spring-data</name>
+	<description>Demo project for Spring Boot</description>
+	<properties>
+		<java.version>11</java.version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-data-jpa</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>com.h2database</groupId>
+			<artifactId>h2</artifactId>
+			<scope>runtime</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<excludes>
+						<exclude>
+							<groupId>org.projectlombok</groupId>
+							<artifactId>lombok</artifactId>
+						</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

spring-data/src/main/java/com/example/spring/data/LibraryController.java

@@ -0,0 +1,40 @@
+package com.example.spring.data;
+
+import com.example.spring.data.model.entity.Book;
+import com.example.spring.data.model.entity.Person;
+import com.example.spring.data.service.LibraryService;
+import com.example.spring.data.service.PersonService;
+import lombok.AllArgsConstructor;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+
+@RestController
+@AllArgsConstructor
+public class LibraryController {
+
+    private final LibraryService libraryService;
+    private final PersonService personService;
+
+    @GetMapping(value = "/join")
+    public ResponseEntity<List<Book>> getAll() {
+        return ResponseEntity.ok(libraryService.getAllByJoinFetch());
+    }
+
+    @GetMapping(value = "/limited")
+    public ResponseEntity<List<Book>> getLimitedFieldsInfo() {
+        return ResponseEntity.ok(libraryService.getAllByLimitLazyFields());
+    }
+
+    @GetMapping(value = "/entity-graph")
+    public ResponseEntity<List<Person>> getByEntityGraph() {
+        return ResponseEntity.ok(personService.findPersons());
+    }
+
+    @GetMapping(value = "/entity-graph-name")
+    public ResponseEntity<List<Person>> getByEntityGraphByName() {
+        return ResponseEntity.ok(personService.findPersonByName());
+    }
+}

spring-data/src/main/java/com/example/spring/data/SpringDataApplication.java

@@ -0,0 +1,13 @@
+package com.example.spring.data;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class SpringDataApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(SpringDataApplication.class, args);
+	}
+
+}

spring-data/src/main/java/com/example/spring/data/model/LibraryRepository.java

@@ -0,0 +1,17 @@
+package com.example.spring.data.model;
+
+import com.example.spring.data.model.entity.Book;
+import org.springframework.data.domain.Sort;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+
+import java.util.List;
+
+public interface LibraryRepository extends JpaRepository<Book, Long> {
+
+    @Query(value = "select b from Book b left join fetch b.authors left join fetch b.readers")
+    List<Book> findAllWithJoinFetch(Sort sort);
+
+    @Query(value = "select new Book(b.id, b.name, b.description) from Book b")
+    List<Book> findAllWithLimitedFields();
+}

spring-data/src/main/java/com/example/spring/data/model/PersonRepository.java

@@ -0,0 +1,17 @@
+package com.example.spring.data.model;
+
+import com.example.spring.data.model.entity.Person;
+import org.springframework.data.jpa.repository.EntityGraph;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+
+import java.util.List;
+
+public interface PersonRepository extends JpaRepository<Person, Long> {
+
+    @Query(value = "select new Person(p.id, p.name, p.info, p.permissions) from Person p left join fetch p.permissions")
+    List<Person> findAll();
+
+    @EntityGraph(value = "Person.all")
+    List<Person> findAllByNameLike(String name);
+}

spring-data/src/main/java/com/example/spring/data/model/entity/Author.java

@@ -0,0 +1,28 @@
+package com.example.spring.data.model.entity;
+
+import lombok.*;
+
+import javax.persistence.*;
+
+@Entity
+@Builder
+@Data
+@ToString(exclude = {"book", "person"})
+@AllArgsConstructor
+@NoArgsConstructor
+public class Author {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    private String description;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Book book;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Person person;
+}

spring-data/src/main/java/com/example/spring/data/model/entity/Book.java

@@ -0,0 +1,42 @@
+package com.example.spring.data.model.entity;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+import javax.persistence.*;
+import java.util.HashSet;
+import java.util.Set;
+
+
+@Entity
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+@NamedEntityGraph(name = "Book.authors",
+        attributeNodes = @NamedAttributeNode("authors")
+)
+public class Book {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    private String description;
+
+    @OneToMany(mappedBy = "book", cascade = CascadeType.ALL)
+    private Set<Author> authors = new HashSet<>();
+
+    @OneToMany(mappedBy = "book", cascade = CascadeType.ALL)
+    private Set<Reader> readers = new HashSet<>();
+
+    public Book(Long id, String name, String description) {
+        this.id = id;
+        this.name = name;
+        this.description = description;
+    }
+}

spring-data/src/main/java/com/example/spring/data/model/entity/Person.java

@@ -0,0 +1,45 @@
+package com.example.spring.data.model.entity;
+
+import com.example.spring.data.model.entity.Author;
+import com.example.spring.data.model.entity.UserPermission;
+import lombok.*;
+
+import javax.persistence.*;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+@Entity
+@Data
+@Builder
+@AllArgsConstructor
+@NoArgsConstructor
+@NamedEntityGraphs({
+        @NamedEntityGraph(
+                name = "Person.all", includeAllAttributes = true
+        )
+})
+public class Person {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    private String info;
+
+    @OneToMany(mappedBy = "person", cascade = CascadeType.ALL)
+    private List<UserPermission> permissions = new ArrayList<>();
+
+    @OneToMany(mappedBy = "person", cascade = CascadeType.ALL)
+    private Set<Author> authors = new HashSet<>();
+
+    public Person(Long id, String name, String info, List<UserPermission> permissions) {
+        this.id = id;
+        this.name = name;
+        this.info = info;
+        this.permissions = permissions;
+    }
+}

spring-data/src/main/java/com/example/spring/data/model/entity/Reader.java

@@ -0,0 +1,29 @@
+package com.example.spring.data.model.entity;
+
+import lombok.*;
+
+import javax.persistence.*;
+
+@Entity
+@Builder
+@Data
+@ToString(exclude = {"book"})
+@AllArgsConstructor
+@NoArgsConstructor
+public class Reader {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    private String lastName;
+
+    private String address;
+
+    private String description;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Book book;
+}

spring-data/src/main/java/com/example/spring/data/model/entity/UserPermission.java

@@ -0,0 +1,23 @@
+package com.example.spring.data.model.entity;
+
+import lombok.*;
+
+import javax.persistence.*;
+
+@Entity
+@Data
+@Builder
+@ToString(exclude = {"person"})
+@AllArgsConstructor
+@NoArgsConstructor
+public class UserPermission {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+
+    private String name;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Person person;
+}