Passing array of reg expressions to spring based mongo #Query - spring

Question

I'm using Spring boot with mongodb. I've extended PagingAndSortingRepository repository and added the following function
#Query("{'title':{ $nin: [?0]}}")
List<Item> findItem(String[] exclude);
I want to be able to pass it an array of regular expressions such as /dog/,/cat/,/horse/ to exclude any item that may have one of these in it's title.
The above function does not work because the exclude is converted to a string. How can I pass an array of regular expressions to be able to do the above?

Answer 1

You can work it out by using a Querydsl predicate in one of your controller method.
Add something like this to your controller:
#RequestMapping(value="/search/findByNameRegexNotIn", method = RequestMethod.GET)
#ResponseBody
public List<Item> findByNameRegexNotIn(#RequestParam(name = "name") List<String> names) {
// build a query predicate
BooleanBuilder predicate = new BooleanBuilder(); // comes from the Querydsl library
for (String name : names) {
predicate.and(QItem.item.name.contains(name).not()); // the QItem class is generated by Querydsl
}
List<Item> items = (List<Item>)repository.findAll(predicate);
return items;
}
You can of course add a Pageable parameter and return a Page<Item> instead of a List.
Edit: another solution if you use Querydsl for this sole purpose is to override the default bindings of your query parameter.
public interface ItemRepository extends CrudRepository<Item, String>,
QueryDslPredicateExecutor<Item>, QuerydslBinderCustomizer<QItem> {
#Override
default public void customize(QuerydslBindings bindings, QItem item) {
bindings.bind(item.name).all(
(path, values) -> path.matches(StringUtils.collectionToDelimitedString(values, "|")).not());
// disable query on all parameters but the item name
bindings.including(item.name);
bindings.excludeUnlistedProperties(true);
}
}
The controller method:
#RequestMapping(value="/search/query", method = RequestMethod.GET)
#ResponseBody
public List<Item> queryItems(
#QuerydslPredicate(root = Item.class) Predicate predicate) {
List<Item> items = (List<Item>)repository.findAll(predicate);
return items;
}
Edit: if you don't wan't to override the default QuerydslBinderCustomizer#customize, you can also implement your own binder and specify it in the controller method.
public interface ItemRepository extends CrudRepository<Item, String>,
QueryDslPredicateExecutor<Item> {
...
}
The controller method:
#RequestMapping(value="/search/query", method = RequestMethod.GET)
#ResponseBody
public List<Item> queryItems(
#QuerydslPredicate(root = Item.class, bindings = ItemBinder.class) Predicate predicate) {
List<Item> items = (List<Item>)repository.findAll(predicate);
return items;
}
The binder class:
class ItemBinder implements QuerydslBinderCustomizer<QItem> {
#Override
public void customize(QuerydslBindings bindings, QItem item) {
bindings.bind(item.name).all(
(path, values) -> path.matches(StringUtils.collectionToDelimitedString(values, "|")).not()
);
bindings.including(item.name);
bindings.excludeUnlistedProperties(true);
}
}
Edit: for the sake of exhaustivity and those who don't want to hear about Querysl. Using the solution proposed in Spring Data Mongodb Reference.
Define a custom repository interface:
interface ItemRepositoryCustom {
public Page<Item> findByNameRegexIn(Collection<String> names, Pageable page);
}
Define an custom repository implementation (Impl postfix required!):
public class ItemRepositoryImpl implements ItemRepositoryCustom {
#Autowired
private MongoOperations operations;
#Override
public Page<Item> findByNameRegexNotIn(Collection<String> names, Pageable pageable) {
String pattern = StringUtils.collectionToDelimitedString(names, "|");
// this time we use org.springframework.data.mongodb.core.query.Query instead of Querydsl predicates
Query query = Query.query(where("name").regex(pattern).not()).with(pageable);
List<Item> items = operations.find(query, Item.class);
Page<Item> page = new PageImpl<>(items, pageable, items.size());
return page;
}
}
Now simply extend ItemRepositoryCustom:
public interface ItemRepository extends MongoRepository<Item, String>, ItemRepositoryCustom {
...
}
And you're done!

Answer 2

You can pass a java.util.regex.Pattern[] to the method. This will be converted to regex array under the hood:
#Query("{'title':{ $nin: ?0}}")
List<Item> findItem(Pattern[] exclude);