You need a way to dynamically filter entities without any effort? Just add me to your pom.xml. Your API will gain a full featured search functionality. You don't work with APIs? No problem, you may still not want to mess with SQL, JPA predicates, security, and all of that I guess.

/search?filter= average(ratings) > 4.5 and brand.name in ('audi', 'land rover') and (year > 2018 or km < 50000) and color : 'white' and accidents is empty

/* Entity used in the query above */
@Entity public class Car {
  @Id long id;
      int year;
      int km;
  @Enumerated Color color;
  @ManyToOne Brand brand;
  @OneToMany List<Accident> accidents;
  @ElementCollection List<Integer> ratings;
  // ...
}

🚀 Yes we support booleans, dates, enums, functions, and even relations! Need something else? Tell us here.

<dependency>
    <groupId>com.turkraft</groupId>
    <artifactId>spring-filter</artifactId>
    <version>2.0.2</version>
</dependency>

Requires javax.persistence-api, spring-data-jpa, spring-web and spring-webmvc

@GetMapping(value = "/search")
public Page<Entity> search(@Filter Specification<Entity> spec, Pageable page) {
  return repo.findAll(spec, page);
}

The repository should implement JpaSpecificationExecutor in order to execute Spring's Specification, SimpleJpaRepository is a well known implementation. You can remove the Pageable argument and return a List if pagination is not needed.

Requires javax.persistence-api, spring-data-jpa, spring-web

Specification<Entity> spec = new FilterSpecification<Entity>(query);

Requires javax.persistence-api

Predicate predicate = ExpressionGenerator.run(String query, Root<?> r, CriteriaQuery<?> q, CriteriaBuilder cb);

⚠️ If you need to search over relations, you also require hibernate-core

/* Using static methods */
import static com.turkraft.springfilter.FilterBuilder.*;
Filter filter = like("name", "%jose%");
String query = filter.generate(); // name ~ '%jose%'
// filter = Filter.from(query);
// Predicate predicate = ExpressionGenerator.run(filter, Root<?> r, CriteriaQuery<?> cq, CriteriaBuilder cb);
// Specification<Entity> spec = new FilterSpecification<Entity>(filter);

Field names should be directly given without any extra literals. Dots indicate nested fields. For example: category.updatedAt

Numbers should be directly given. Booleans should also directly be given, valid values are true and false (case insensitive). Others such as strings, enums, dates, should be quoted. For example: status : 'active'

You may prioritize operators using parentheses, for example: x and (y or z)

Note that the * character can also be used instead of % when using the ~ comparator. By default, this comparator is case insensitive, the behavior can be changed with FilterParameters.CASE_SENSITIVE_LIKE_OPERATOR.

A function is characterized by its name (case insensitive) followed by parentheses. For example: currentTime(). Some functions might also take arguments, arguments are seperated with commas. For example: min(ratings) > 3

You are able to change the date format by setting the static formatters inside the FilterParameters class. You may see below the default patterns and how you can set them with properties:

MongoDB is also partially supported as an alternative to JPA. The query input is compiled to a Bson/Document filter. You can then use it as you wish with MongoTemplate or MongoOperations for example.

Requires spring-data-mongodb

@GetMapping(value = "/search")
public Page<Entity> search(@Filter(entityClass = Entity.class) Document doc, Pageable page) {
  // your repo may implement DocumentExecutor for easy usage
  return repo.findAll(doc, page); 
}

Bson bson = BsonGenerator.run(Filter.from(query), Entity.class);
Document doc = BsonUtils.getDocumentFromBson(bson);
Query query = BsonUtils.getQueryFromDocument(doc);
// ...

⚠️ Functions are currently not supported with MongoDB, and the ~ operator actually uses the regex operator

If you need to customize the behavior of the filter, the way to go is to extend the FilterBaseVisitor class, by taking QueryGenerator or ExpressionGenerator as examples. In order to also modify the query syntax, you should start by cloning the repository and editing the Filter.g4 file.

• Easily filter entities in your Spring API

Ideas and pull requests are always welcome. Google's Java Style is used for formatting.

Thanks to @marcopag90 and @glodepa for adding support to MongoDB.

Distributed under the MIT license.