Rich Criteria API for JPA providers
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README.md

Build Status

Maven Central Slack Status

Javadoc - Core Javadoc - Entity-View Javadoc - JPA-Criteria

Blaze-Persistence

Blaze-Persistence is a rich Criteria API for JPA providers.

What is it?

Blaze-Persistence is a rich Criteria API for JPA providers that aims to be better than all the other Criteria APIs available. It provides a fluent API for building queries and removes common restrictions encountered when working with JPA directly. It offers rich pagination support and also supports keyset pagination.

The Entity-View module can be used to create views for JPA entites. You can roughly imagine an entity view is to an entity, what a RDBMS view is to a table.

The JPA-Criteria module implements the Criteria API of JPA but is backed by the Blaze-Persistence Core API so you can get a query builder out of your CriteriaQuery objects.

Features

Blaze-Persistence is not only a Criteria API that allows to build queries easier, but it also comes with a lot of features that are normally not supported by JPA providers.

Here is a rough overview of new features that are introduced by Blaze-Persistence

  • Use CTEs and recursive CTEs
  • Use modification CTEs aka DML in CTEs
  • Make use of the RETURNING clause from DML statements
  • Use the VALUES clause for reporting queries and soon make use of table generating functions
  • Create queries that use SET operations like UNION, EXCEPT and INTERSECT
  • Define functions similar to Hibernates SQLFunction in a JPA provider agnostic way
  • Use many built-in functions like GROUP_CONCAT, date extraction, date arithmetic and many more
  • Easy pagination and simple API to make use of keyset pagination

In addition to that, Blaze-Persistence also works around some JPA provider issues in a transparent way.

How to use it?

Blaze-Persistence is split up into different modules. We recommend that you define a version property in your parent pom that you can use for all artifacts. Modules are all released in one batch so you can safely increment just that property.

<properties>
    <blaze-persistence.version>1.2.0.Alpha1</blaze-persistence.version>
</properties>

Quickstart

If you want a sample application with everything setup where you can poke around and try out things, just go with our archetypes!

Core-only archetype:

mvn archetype:generate "-DarchetypeGroupId=com.blazebit" "-DarchetypeArtifactId=blaze-persistence-archetype-entity-view-sample" "-DarchetypeVersion=1.2.0-SNAPSHOT"

Entity view archetype:

mvn archetype:generate "-DarchetypeGroupId=com.blazebit" "-DarchetypeArtifactId=blaze-persistence-archetype-core-sample" "-DarchetypeVersion=1.2.0-SNAPSHOT"

Spring-Data archetype:

mvn archetype:generate "-DarchetypeGroupId=com.blazebit" "-DarchetypeArtifactId=blaze-persistence-archetype-spring-data-sample" "-DarchetypeVersion=1.2.0-SNAPSHOT"

Manual setup

For compiling you will only need API artifacts and for the runtime you need impl and integration artifacts. Choose the integration artifacts based on your JPA provider.

Blaze-Persistence Core module dependencies

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-core-api</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-core-impl</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Blaze-Persistence Entity-View module dependencies

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-entity-view-api</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-entity-view-impl</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Blaze-Persistence Entity-View CDI integration dependencies

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-entity-view-cdi</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Blaze-Persistence Entity-View Spring integration dependencies

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-entity-view-spring</artifactId>
    <version>${blaze-persistence.version}</version>
</dependency>

Blaze-Persistence JPA provider integration module dependencies

Hibernate 5.2

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-hibernate-5.2</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Hibernate 5+

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-hibernate-5</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Hibernate 4.3

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-hibernate-4.3</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Hibernate 4.2

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-hibernate-4.2</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Datanucleus

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-datanucleus</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

EclipseLink

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-eclipselink</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

OpenJPA

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-integration-openjpa</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Blaze-Persistence JPA-Criteria module dependencies

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-jpa-criteria-api</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>compile</scope>
</dependency>
<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-jpa-criteria-impl</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Blaze-Persistence JPA-Criteria JPA 2.0 provider support dependencies

<dependency>
    <groupId>com.blazebit</groupId>
    <artifactId>blaze-persistence-jpa-criteria-jpa-2-compatibility</artifactId>
    <version>${blaze-persistence.version}</version>
    <scope>runtime</scope>
</dependency>

Documentation

The current documentation is still pretty raw and we are happy about every contribution! The documentation is split into a reference for the core module and for the entity-view module.

Core quick-start

First you need to create a CriteriaBuilderFactory which is the entry point to the core api.

CriteriaBuilderConfiguration config = Criteria.getDefault();
// optionally, perform dynamic configuration
CriteriaBuilderFactory cbf = config.createCriteriaBuilderFactory(entityManagerFactory);

NOTE: The CriteriaBuilderFactory should have the same scope as your EntityManagerFactory as it is bound to it.

For demonstration purposes, we will use the following simple entity model.

@Entity
public class Cat {
    @Id
    private Integer id;
    private String name;
    @ManyToOne(fetch = FetchType.LAZY)
    private Cat father;
    @ManyToOne(fetch = FetchType.LAZY)
    private Cat mother;
    @OneToMany
    private Set<Cat> kittens;
    // Getter and setters omitted for brevity
}

If you want select all cats and fetch their kittens as well as their father you do the following.

cbf.create(em, Cat.class).fetch("kittens.father").getResultList();

This will create quite a query behind the scenes:

SELECT cat FROM Cat cat LEFT JOIN FETCH cat.kittens kittens_1 LEFT JOIN FETCH kittens_1.father father_1

An additional bonus is that the paths and generally every expression you write will get checked against the metamodel so you can spot typos very early.

Entity-view usage

Every project has some kind of DTOs and implementing these properly isn't easy. Based on the super quick-start model we will show how entity views come to the rescue!

To make use of entity views, you will need a EntityViewManager with entity view classes registered. In a CDI environment you can inject a EntityViewConfiguration that has all discoverable entity view classes registered, but in a normal Java application you will have to register the classes yourself like this:

EntityViewConfiguration config = EntityViews.createDefaultConfiguration();
config.addEntityView(CatView.class);
EntityViewManager evm = config.createEntityViewManager(criteriaBuilderFactory, entityManagerFactory);

NOTE: The EntityViewManager should have the same scope as your EntityManagerFactory and CriteriaBuilderFactory as it is bound to it.

The entity view itself is a simple interface describing the structure of the projection that you want. It is very similar to defining an entity class with the difference that it is based on the entity model instead of the DBMS model.

@EntityView(Cat.class)
public interface CatView {
    @IdMapping("id")
    public Integer getId();

    @Mapping("CONCAT(mother.name, 's kitty ', name)")
    public String getCuteName();

    public SimpleCatView getFather();

}
@EntityView(Cat.class)
public interface SimpleCatView {
    @IdMapping("id")
    public Integer getId();

    public String getName();

}

The CatView has a property cuteName which will be computed by the JPQL expression CONCAT(mother.name, 's kitty ', name) and a subview for father. Note that every entity view needs an id mapping except for EmbeddableEntityView classes. The SimpleCatView is the projection which is used for the father relation and only consists of the id and the name of the Cat.

You just created two DTO interfaces that contain projection information. Now the interesting part is that entity views can be applied on any query, so you can define a base query and then create the projection like this:

CriteriaBuilder<Cat> cb = criteriaBuilderFactory.create(entityManager, Cat.class);
cb.whereOr()
    .where("father").isNull()
    .where("father.name").like().value("Darth%").noEscape()
.endOr();
CriteriaBuilder<CatView> catViewBuilder = evm.applySetting(EntityViewSetting.create(CatView.class), cb);
List<CatView> catViews = catViewBuilder.getResultList();

This will behind the scenes execute the following optimized query and transparently build your entity view objects based on the results.

SELECT
    cat.id,
    CONCAT(mother_1.name, 's kitty ', cat.name),
    father_1.id,
    father_1.name
FROM Cat cat
LEFT JOIN cat.father father_1
LEFT JOIN cat.mother mother_1
WHERE father_1 IS NULL
   OR father_1.name LIKE :param_0

See the left joins created for relations used in the projection? These are implicit joins which are by default what we call "model-aware". If you specified that a relation is optional = false, we would generate an inner join instead. This is different from how JPQL path expressions are normally interpreted, but in case of projections like in entity views, this is just what you would expect! You can always override the join type of implicit joins with joinDefault if you like.

Questions or issues

Drop by on Slack Status and ask questions any time or just create an issue on GitHub or ask on Stackoverflow.

Setup local development

Here some notes about setting up a local environment for testing.

Building the website and documentation

You have to install GraphViz and make it available in your PATH. It's easiest to just invoke ./serve-website.sh which builds the documentation, website and starts an embedded server to serve at port 8820.

Checkstyle in IntelliJ

. Build the whole thing with mvn clean install once to have the checkstyle-rules jar in your M2 repository . Install the CheckStyle-IDEA Plugin . After a restart, go to Settings > Other Settings > Checkstyle . Add a Third party check that points to the checkstyle-rules.jar of your M2 repository . Add a configuration file named Blaze-Persistence Checkstyle rules pointing to checkstyle-rules/src/main/resources/blaze-persistence/checkstyle-config.xml . Use target/checkstyle.cache for the property checkstyle.cache.file

Now you should be able to select Blaze-Persistence Checkstyle rules in the dropdown of the CheckStyle window. + Click on Check project and checkstyle will run once for the whole project, then it should do some work incrementally.

Firebird

When installing the 3.x version, you also need a 3.x JDBC driver. Additionally you should add the following to the firebird.conf

WireCrypt = Enabled

After creating the DB with create database 'localhost:test' user 'sysdba' password 'sysdba';, you can connect with JDBC with jdbc:firebirdsql:localhost:test?charSet=utf-8

Oracle

When setting up Oracle locally, keep in mind that when you connect to it, you have to set the NLS_SORT to BINARY. Since the JDBC driver derives values from the locale settings of the JVM, you should set the default locale settings to en_US. In IntelliJ when defining the Oracle database, go to the Advanced tab an specify the JVM options -Duser.country=us -Duser.language=en.

When using the Oracle docker container via docker_db.sh oracle you might want to specify the following properties when executing tests -Djdbc.url=jdbc:oracle:thin:@192.168.99.100:1521/xe -Djdbc.user=SYSTEM -Djdbc.password=oracle

JDBC Driver

You have to install the JDBC driver manually. If you install Oracle XE locally, you can take it from $ORACLE_HOME/jdbc otherwise download it from http://www.oracle.com/technetwork/database/features/jdbc/index-091264.html Copy the jar to $M2_HOME/com/oracle/ojdbc14/10.2.0.4.0/ojdbc14-10.2.0.4.0.jar and you should be good to go.

If you use the docker container, extract the jdbc driver from the container via docker cp oracle:/u01/app/oracle/product/11.2.0/xe/jdbc/lib/ojdbc6.jar ojdbc.jar

mvn -q install:install-file -Dfile=ojdbc.jar -DgroupId=com.oracle -DartifactId=ojdbc14 -Dversion=10.2.0.4.0 -Dpackaging=jar -DgeneratePom=true

Install Oracle locally

Download Oracle XE from http://www.oracle.com/technetwork/database/database-technologies/express-edition/downloads/index.html During installation use the password "oracle" which is also the default password for the docker image.

DB2

When using the DB2 docker container via docker_db.sh db2 you might want to specify the following properties when executing tests -Djdbc.url=jdbc:db2://192.168.99.100:50000/test -Djdbc.user=db2inst1 -Djdbc.password=db2inst1-pwd

JDBC Driver

You have to install the JDBC driver manually. If you install DB2 Express locally, you can take it from $DB2_HOME/sqllib/java otherwise download it from http://www-01.ibm.com/support/docview.wss?uid=swg21363866

When using the docker container, you can find in the copy script to extract the JDBC driver from the container in docker_db.sh. Install via the following commands.

mvn -q install:install-file -Dfile=db2jcc4.jar -DgroupId=com.ibm.db2 -DartifactId=db2jcc4 -Dversion=9.7 -Dpackaging=jar -DgeneratePom=true

mvn -q install:install-file -Dfile=db2jcc_license_cu.jar -DgroupId=com.ibm.db2 -DartifactId=db2jcc_license_cu -Dversion=9.7 -Dpackaging=jar -DgeneratePom=true

SQL Server

When using the DB2 docker container via docker_db.sh mssql you might want to specify the following properties when executing tests -Djdbc.url=jdbc:sqlserver://192.168.99.100:1433

JDBC Driver

Since the JDBC driver is officially available in Maven central, you don't have to separately install it.

Website deployment

You can use build-deploy-website.sh to deploy to the target environment but need to configure in ~/.m2/settings.xml the following servers.

Id: staging-persistence.blazebit.com User/Password: user/****

Id: persistence.blazebit.com User/Password: user/****

Licensing

This distribution, as a whole, is licensed under the terms of the Apache License, Version 2.0 (see LICENSE.txt).

References

Project Site: https://persistence.blazebit.com