Spring Data MongoDB Repository - JPA Specifications like

Question

Is there something like JPA Specifications for Spring Data MongoDB Repositories?

If not, how can I make dynamic queries with repositories?

A classic scenario could be a search form with optional fields that the user will fill.

Kenny

Answer 1

I found myself a way.

The trick can be done using QueryDSL, in the following way:

First, add the QueryDSL dependencies:

<dependency>
    <groupId>com.mysema.querydsl</groupId>
    <artifactId>querydsl-mongodb</artifactId>
    <version>${querydsl-mongo.version}</version>
</dependency>

<dependency>
    <groupId>com.mysema.querydsl</groupId>
    <artifactId>querydsl-apt</artifactId>
    <version>${querydsl-mongo.version}</version>
</dependency>

Then, configure the plugin in order to create Metamodels classes (their names will be the same of the documents with the letter Q as prefix: eg. QUser):

    <build>
        <plugins>
            ....
            <plugin>
                <groupId>com.mysema.maven</groupId>
                <artifactId>apt-maven-plugin</artifactId>
                <version>1.1.3</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>process</goal>
                        </goals>
                        <configuration>
                            <outputDirectory>target/generated-sources/java</outputDirectory>
                            <processor>org.springframework.data.mongodb.repository.support.MongoAnnotationProcessor</processor>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

Note the processor class: it's not the QueryDSL default one com.mysema.query.apt.morphia.MorphiaAnnotationProcessor, but the Spring Data MongoDB one org.springframework.data.mongodb.repository.support.MongoAnnotationProcessor:

Spring Data Mongo provides a custom APT processor to generate the Metamodels instead of the one provided in QueryDSL, it will scan the Spring specific @Document instead of the Morphia specific annotations.

Now we can make our repository interface extending QueryDslPredicateExecutor<T>:

public interface UserRepository extends MongoRepository<User, String>, QueryDslPredicateExecutor<User>,
        QuerydslBinderCustomizer<QUser> {
}

We can now define Predicates when querying the repository:

QUser user = QUser.user;            
BooleanExpression predicate = user.name.containsIgnoreCase("John");         
userRepository.findAll(predicate);

QuerydslBinderCustomizer helps you to define the binding of the Document's properties (see Spring documentation for further help).

Kenny

For an implementation of this and also for the reactive version, there is an example: github.com/spring-projects/spring-data-examples/tree/master/… – Herbie

Answer 2

This is update as of:

<spring.version>4.3.4.RELEASE</spring.version>
<querydsl.version>4.1.3</querydsl.version>
<spring.data.mongodb.version>1.9.5</spring.data.mongodb.version>

use

...
            <plugin>
            <groupId>com.mysema.maven</groupId>
            <artifactId>apt-maven-plugin</artifactId>
            <version>1.1.3</version>
            <executions>
                <execution>
                    <goals>
                        <goal>process</goal>
                    </goals>
                    <configuration>
                        <outputDirectory>target/generated-sources/java</outputDirectory>
                        <processor>org.springframework.data.mongodb.repository.support.MongoAnnotationProcessor</processor>
                    </configuration>
                </execution>
            </executions>
        </plugin>
...

    <dependency>
        <groupId>com.querydsl</groupId>
        <artifactId>querydsl-mongodb</artifactId>
        <version>${querydsl.version}</version>
    </dependency>

    <dependency>
        <groupId>com.querydsl</groupId>
        <artifactId>querydsl-apt</artifactId>
        <version>${querydsl.version}</version>
    </dependency>

Redintegration