Wrap your Database in Java 8

Per-Åke MinborgCarina DreifeldtMalin WeissEmil Forslund

Speedment

Company• Company started 2010• Speedment customers:

Fintech, manufacturing, media, telecom, transport, retail, publishing and entertainment.

•Office Palo Alto, California Gothenburg, Sweden

Open Source Project• Apache 2, started 2015• Fully Java 8 compatible• www.speedment.org, GitHub

Bio Per-Åke Minborg• Master of Science Sweden• Inventor and Serial Entrepreneur• Java >15 years• Speaker at Meetups and Javaforums around

the globe, (Java-One 2015)• Java 8 and OpenSource blogger

Speedment Started With A Problem

Do You Recognize the following?• When coding it is complex to connect to a database…..

…then you use an ORM

Source: ZeroTurnaround

SOME PROS of Using an ORM:• You can work with a relational database as if it were object oriented.• Increased productivity.• Provides a certain degree of abstraction (you can replace your

DBMS).

SOME CONS of Using an ORM:• Slows down the application• You must still write SQL, HQL, et. al• You can not access all Java 8 features

How to skip these ORMs and work with Pure Java 8

• Lambda expressions• Stream API• Optional

Lambda Expressions• Anonymous methods can be expressed using the new ”->”

syntax

Deck deck = Deck.createShuffledDeck();List<Card> cards = deck.findWhere(card -> card.isHeart() && card.getValue() > 10);

Lambda Expressions• Any single-method interface can be implemented using lambda • can be annoted with @FunctionalInterface to show this

@FunctionalInterfaceinterface VectorOperation { Vector apply(Vector a, Vector b);}

VectorOperation plus = (a, b) -> new Vector( a.getX() + b.getX(), a.getY() + b.getY());

Lambda Expressions Functional pointers can also be used with the ”::” syntax

Set<Hero> warriors = typicalParty.where(Hero::isWarrior);…interface Hero { boolean isWarrior();}…class Party { private Set<Hero> heroes;

public Set<Hero> select(Predicate<Hero> selector) { … }}

Stream API• Streams are a modern way of working with groups of elements• Defining a stream is always an O(1)-operation• The elements are only traversed when used• Streams can often be executed in parallell

Stream API• Example: Get the average strength of all warriors with axes in the

party

Set<Hero> party = … ;int averageStrength = party.stream() .filter(hero -> Archtype.WARRIOR == hero.getArchtype()) .filter(hero -> Weapon.AXE == hero.getWeapon()) .mapToInt(Hero::getStrength) .average();

By replacing .stream() with .parallelStream() the operation can be performed using multiple processors

Optional• Null is often described as ”The Billion Dollar Mistake” of modern

programming languages• Using the Optional-interface we can now describe a value that might or

might not be present in a null-safe way

String getEmailAddress() { // Is always defined return this.emailAddress;}

Optional<String> getFirstname() { // Might not exist return Optional.ofNullable( this.firstname );}

Optional• You can work with Optionals in the same way you work with

streamsOptional<String> firstname = getFirstname() .filter(fn -> fn.length() > 3) .filter(fn -> fn.charAt(0) == 'A');

• When the value of an optional is retreived, you can handle every caseString absoluteFirstname = firstname.getOrDefault("Anonymous");

Speedment APIEmbrace Java 8 paradigm with stream(), filter(), sort(), limit() etc.

Forget about SQL, JQLFocus on Business Logic

Focus on what is fun

Develop a Database app within hours

No Query API

Stick to Java 8

Initialization

Speedment speedment = new HelloSpeedment().build();

Manager<Hare> hares = speedment.managerOf(Hare.class);

Persistence

Hare spire = hares.newInstance() .setName(“Spire") .setColor(“Blue") .setAge(1) .persist();

Querying

List<Hare> oldHares = hares.stream() .filter(h -> h.getAge() > 8) .collect(toList());

Optimised Predicate Look-up

Optional<Hare> spire= hares.stream() .filter(Hare.NAME.equal(“Spire")) .findAny();

Entities are Linked

Optional<Carrot> carrot = hares.stream() .filter(Hare.NAME.equal(“Spire”)) // Carrot is a foreign key. .flatMap(Hare::findCarrots) .findAny();

Multi-threading

hares.stream() .parallel() .filter(h -> humans.stream() .filter(Human.NAME.equal(h.getName())) .anyMatch() ).forEach(System.out::println);

Configuration• Groovy script like Gradle• Config file is placed relative to the POM

dbms { schema { table { name = ”hare"; column { name = "name"; } } }}

Ease of use:• Single Maven dependency in POM • Maven plugin for code generation/GUI• Maven targets• Works with Gradle• GUI to automatically derive the groovy config file from existing

databases

Conclusions• Code generation, No boiler plate code• Focus on the problem at hand!• Forget about the database• Use Java 8

Workshop: Social network We will focus on the server-side

MySQL database

Server application

Client GUI

http

Workshop: Social NetworkThe goal is to add features:

• Register• Login• Upload pictures

Workshop: Social Network Speedment: https://

github.com/speedment/speedment

https://github.com/Pyknic/SocialPhotoNetworkClient

Social Network Lab : https://github.com/Pyknic/SocialPhotoNetworkServer

Insane Mode...Want fast development + super duper fast execution ?

Speedment Enterprise Solution provides extreme performance

We are Where You are!• www.speedment.org

• GitHub: https://github.com/speedment/speedment

• Twitter: @Pminborg

• Mail: minborg@speedment.org

• Blog: minborgsjavapot.blogspot.com

• Silicon Valley