This module contains examples showing how JPAstreamer can be used in conjunction with Hibernate. Although, please note that JPAstreamer can be used with any JPA provider.
The demo makes use of the MySQL Sakila database. It can either be downloaded from Oracle as described here or used directly via a Sakila Docker instance by issuing the following commands:
$ docker pull restsql/mysql-sakila
$ docker run -d --publish 3306:3306 --name mysqld restsql/mysql-sakilaNOTE: This Docker image does not support ARM64 architecture, thus if you are running on e.g. an M1 Mac, you need to emulate an Intel image by adding the flag '--platform linux/amd64' after 'docker run' in the above command. This may not always work ideally, learn more about why at the Docker webpage.
Open the project as a Maven project in your IDE and execute any of the main-methods in one of the Demo-classes.
To execute any of the demos, use the command mvn install exec:java@ followed by the demo name. For example:
mvn install exec:java@SimpleDemo1 Below is a summary of the included examples.
SimpleDemo1 shows how to create a stream of films of length between 100 and 120 minutes.
jpaStreamer.stream(Film.class)
.filter(Film$.length.between(100, 120))
.forEach(SimpleDemo1::printFilm);Prints:
These are the films that are of length between 100 and 120 minutes:
4 AFFAIR PREJUDICE G 117
9 ALABAMA DEVIL PG-13 114
19 AMADEUS HOLY PG 113
32 APOCALYPSE FLAMINGOS R 119
44 ATTACKS HATE PG-13 113
46 AUTUMN CROW G 108
48 BACKLASH UNDEFEATED PG-13 118
54 BANGER PINOCCHIO R 113
62 BED HIGHBALL NC-17 106
65 BEHAVIOR RUNAWAY PG 100
Automatic Stream to JPA rendering:
select
Film
from
Film as Film
where
Film.length between 100 and 120
Automatic JPA to Hibernate SQL rendering:
select
film0_.film_id as film_id1_1_,
film0_.description as descript2_1_,
film0_.language_id as languag11_1_,
film0_.last_update as last_upd3_1_,
film0_.length as length4_1_,
film0_.rating as rating5_1_,
film0_.rental_duration as rental_d6_1_,
film0_.rental_rate as rental_r7_1_,
film0_.replacement_cost as replacem8_1_,
film0_.special_features as special_9_1_,
film0_.title as title10_1_
from
film film0_
where
film0_.length between 100 and 120
CountDemo shows how to perform a count of all the elements that matches the query.
long count = jpaStreamer.stream(Film.class)
.filter(Film$.length.between(100, 120))
.count(); SimpleDemo1WithJoining as SimpleDemo1 but showing how to join in fields avoiding the "N + 1 select problem".
jpaStreamer.stream(of(Film.class).joining(Film$.actors).joining(Film$.language))
.filter(Film$.length.between(100, 120))
.forEach(SimpleDemo1::printFilm);SimpleDemo2 shows how to select five films with rating G, sort them by descending length and skip the first ten entries.
jpaStreamer.stream(Film.class)
.filter(Film$.rating.equal("G"))
.sorted(Film$.length.reversed().thenComparing(Film$.title.comparator()))
.skip(10)
.limit(5)
.forEach(SimpleDemo2::printFilm);Prints:
126 CASUALTIES ENCINO G 179
692 POTLUCK MIXED G 179
897 TORQUE BOUND G 179
958 WARDROBE PHANTOM G 178
280 EMPIRE MALKOVICH G 177
PaginationDemo demonstrates how to serve a page request from a GUI or a similar application.
return jpaStreamer.stream(Film.class)
.sorted(comparator)
.skip(page * PAGE_SIZE)
.limit(PAGE_SIZE)
.collect(Collectors.toList());Prints:
CYCLONE FAMILY
DADDY PITTSBURGH
DAISY MENAGERIE
DALMATIONS SWEDEN
DANCES NONE
DANCING FEVER
DANGEROUS UPTOWN
...
PivotDemo demonstrates how to make a pivot table containing all the actors and the number of films they have participated in for each film rating category (e.g. “PG-13”).
Map<Actor, Map<String, Long>> pivot = jpaStreamer.stream(Actor.class)
.collect(
groupingBy(Function.identity(),
Collectors.flatMapping(a -> a.getFilms().stream(),
groupingBy(Film::getRating, counting())
)
)
);Prints:
SCARLETT BENING: {PG-13=7, R=5, NC-17=4, PG=5, G=5}
WOODY HOFFMAN: {PG-13=7, R=6, NC-17=5, PG=6, G=7}
ED MANSFIELD: {PG-13=4, R=8, NC-17=9, PG=5, G=6}
PARKER GOLDBERG: {PG-13=9, R=4, NC-17=5, G=2, PG=4}
...
PartitionDemo demonstrates how to partiton films into two buckets depending on film length:
Map<Boolean, List<Film>> map = jpaStreamer.stream(Film.class)
.collect(
Collectors.partitioningBy(Film$.length.greaterThan(120))
);Prints:
long is false has 543 films
long is true has 457 films
OneToManyDemo maps the languages to a list of all films that are spoken in that language.
Map<Language, Set<Film>> languageFilmMap = jpaStreamer.stream(Language.class)
.limit(10)
.collect(
toMap(Function.identity(),Language::getFilms)
);Prints:
French: []
Mandarin: []
Italian: []
English: [INFORMER DOUBLE, CITIZEN SHREK, OCTOBER SUBMARINE, ANACONDA CONFESSIONS, ...]
German: []
...
ManyToOneDemo maps every film with rating PG-13 to its spoken language.
Map<Film, Language> languageMap = jpaStreamer.stream(Film.class)
.filter(Film$.rating.equal("PG-13"))
.collect(
Collectors.toMap(Function.identity(), Film::getLanguage)
);Prints:
EXPECATIONS NATURAL: English
SINNERS ATLANTIS: English
TRIP NEWTON: English
WRONG BEHAVIOR: English
STRICTLY SCARFACE: English
MICROCOSMOS PARADISE: English
...
ManyToManyDemo demonstrates how to create a filmography that maps every actor to a list of films that they have starred in.
Map<Actor, List<Film>> filmography = jpaStreamer.stream(Actor.class)
.collect(
Collectors.toMap(Function.identity(), Actor::getFilms)
);Prints:
MARY TANDY: [BARBARELLA STREETCAR, CHILL LUCK, DANGEROUS UPTOWN, ...]
KEVIN BLOOM: [AMERICAN CIRCUS, BOOGIE AMELIE, CITIZEN SHREK, ...]
DUSTIN TAUTOU: [AFRICAN EGG, AUTUMN CROW, BANGER PINOCCHIO, ...]
...
TransactionDemo demonstrates a JPA transaction that updates the rental rate of a selection of films.
try {
em.getTransaction().begin();
jpaStreamer.stream(Film.class)
.filter(Film$.rating.equal("R"))
.forEach(f -> {
f.setRentalRate(f.getRentalRate() + 1);
em.merge(f);
}
);
em.getTransaction().commit();
} catch(Exception e) {
e.printStackTrace();
em.getTransaction().rollback();
}Prints:
Rental rates before raise:
The rental rate for AIRPORT POLLOCK is $4.990000.
The rental rate for ALONE TRIP is $0.990000.
The rental rate for AMELIE HELLFIGHTERS is $4.990000.
The rental rate for AMERICAN CIRCUS is $4.990000.
The rental rate for ANACONDA CONFESSIONS is $0.990000.
...
Rental rates after the raise:
The rental rate for AIRPORT POLLOCK is $5.990000.
The rental rate for ALONE TRIP is $1.990000.
The rental rate for AMELIE HELLFIGHTERS is $5.990000.
The rental rate for AMERICAN CIRCUS is $5.990000.
The rental rate for ANACONDA CONFESSIONS is $1.990000.
...
This repository is configured to work without modification if you use the Docker instance. However, we provide you with details about the Maven and Hibernate configuration below if you wish to set up your own tests.
The following main dependencies are needed for the project:
<dependencies>
<dependency>
<groupId>com.speedment.jpastreamer</groupId>
<artifactId>core</artifactId>
<version>${jpa-streamer-version}</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
<version>5.4.17.Final</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.21</version>
</dependency>
</dependencies>
Here is the complete pom.xml file.
The demos are using Hibernate as the JPA provider. The resources/META-INF/persistence.xml file looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.2"
xmlns="http://xmlns.jcp.org/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
http://xmlns.jcp.org/xml/ns/persistence/persistence_2_2.xsd">
<persistence-unit name="sakila" transaction-type="RESOURCE_LOCAL">
<description>Test</description>
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
<properties>
<!-- Configuring The Database Connection Details -->
<property name="javax.persistence.jdbc.driver" value="com.mysql.cj.jdbc.Driver" />
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/sakila" />
<property name="javax.persistence.jdbc.user" value="root" />
<property name="javax.persistence.jdbc.password" value="sakila" />
<!-- <property name="hibernate.show_sql" value="true"/> -->
<property name="hibernate.format_sql" value="true"/>
<property name="hibernate.use_sql_comments" value="true"/>
<!-- <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL8Dialect"/>-->
</properties>
</persistence-unit>
</persistence>As can be seen, the persistence name is "sakila" and this name is consequently used by JPAstreamer in the demos above.
- JPAstreamer on GitHub - https://github.com/speedment/jpa-streamer
- Documentation - https://speedment.github.io/jpa-streamer
- Gitter Chat - https://gitter.im/speedment/jpa-streamer
- Website - www.jpastreamer.org