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?

Answer 1

I found myself a way.

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

First, add the QueryDSL dependencies:

    com.mysema.querydsl
    querydsl-mongodb
    ${querydsl-mongo.version}



    com.mysema.querydsl
    querydsl-apt
    ${querydsl-mongo.version}

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):

    
        
            ....
            
                com.mysema.maven
                apt-maven-plugin
                1.1.3
                
                    
                        
                            process
                        
                        
                            target/generated-sources/java
                            org.springframework.data.mongodb.repository.support.MongoAnnotationProcessor
                        
                    
                
            
        
    

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:

public interface UserRepository extends MongoRepository, QueryDslPredicateExecutor,
        QuerydslBinderCustomizer {
}

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).