Spring Data Jpa Streamable Return Type

Spring Data Jpa provides a Streamable interface, its acustom extension of Iterable interface. Streamable interface can be used an alternative to Iterable interface or any of the collection type. Iterable interface is good for basic loops of java, but dosent provide support for stream or parallel streams. Streamable interface provides a lot of convieient methods to access non parallel streams, which can be futher enhaced for filter or map.

drop database if exists AppleDb;
create database AppleDb;
use AppleDb;
create TABLE apple ( apple_id BIGINT NOT NULL, apple_name VARCHAR(255) DEFAULT NULL,rating int(1) DEFAULT NULL, PRIMARY KEY (apple_id)) ENGINE=INNODB;
create TABLE hibernate_sequence ( next_val BIGINT) ENGINE=INNODB;

insert into hibernate_sequence values ( 1 );
insert into apple (apple_name, apple_id, taste) values ("Macintosh", 1, "tangy");
insert into apple (apple_name, apple_id, taste) values ("Fuji", 2, "sweet");
insert into apple (apple_name, apple_id, taste) values ("Gala", 3, "juicy");
insert into apple (apple_name, apple_id, taste) values ("Jonagold", 4, "firm sweet");
insert into apple (apple_name, apple_id, taste) values ("GrannySmith", 5, "sharp");

package com.sujan.example.jpa.controller;

import com.sujan.example.jpa.entity.Apple;
import com.sujan.example.jpa.repository.AppleRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.util.Streamable;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.stream.Stream;

@RestController
public class AppleController {
    @Autowired
    private AppleRepository appleRepository;

    @GetMapping
    Stream<Apple> findAll() {
        Streamable<Apple> apple = appleRepository.findByAppleName("Macintosh");
        apple.filter(app -> app.getAppleId() % 2 == 0).forEach(System.out::println);
        return apple.get();
    }
}

package com.sujan.example.jpa.entity;

import lombok.Data;
import lombok.NoArgsConstructor;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

@Data
@Entity
@NoArgsConstructor
public class Apple {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long appleId;
    private String appleName;
    private int rating;
}

package com.sujan.example.jpa.repository;

import com.sujan.example.jpa.entity.Apple;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.util.Streamable;
import org.springframework.stereotype.Repository;

@Repository
public interface AppleRepository extends JpaRepository<Apple, Long> {
    Streamable<Apple> findByAppleName(String appleName);
}

package com.sujan.example.jpa;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class JpaApplication {
    public static void main(String[] args) {
        SpringApplication.run(JpaApplication.class, args);
    }
}

spring.datasource.url=jdbc:mysql://localhost:3306/AppleDb
spring.datasource.username=root
spring.datasource.password=root

plugins {
    id 'org.springframework.boot' version '2.3.3.RELEASE'
    id 'io.spring.dependency-management' version '1.0.10.RELEASE'
    id 'java'
}
group = 'com.sujan'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'
configurations {
    compileOnly {
        extendsFrom annotationProcessor
    }
}
repositories {
    mavenCentral()
}
dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    annotationProcessor 'org.projectlombok:lombok'
    compileOnly 'org.projectlombok:lombok'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    runtimeOnly 'mysql:mysql-connector-java'
    testImplementation('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
}
test {
    useJUnitPlatform()
}

curl --location --request GET 'http://localhost:8080/'

select apple0_.apple_id as apple_id1_0_, apple0_.apple_name as apple_na2_0_, apple0_.taste as taste3_0_ from apple apple0_ where apple0_.apple_name=?
Apple(appleId=2, appleName=Macintosh, taste=tangy)
Apple(appleId=4, appleName=Macintosh, taste=sweet)
Apple(appleId=6, appleName=Macintosh, taste=juicy)
Apple(appleId=8, appleName=Macintosh, taste=tart)

Spring Data Jpa Streamable Return Type

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