Spring with Query Dsl custom binding and or operation doesn't work

Question

i have following reQuirement Query:

"/article?category=kitchen&category=sports"

This Query is working without custom bindings. It will give me all Kitchen and sports articles as Response. It is doing an OR-Operation somehow.

But i need to customize the binding because i need to ingore the case. Now i am using this customize binding:

@Repository
public interface ArticleRepository extends JpaRepository<Article, Long>, 
QueryDslPredicateExecutor<QArticle>, QuerydslBinderCustomizer<QArticle> {


 @Override
  default public void customize(QuerydslBindings bindings, QArticle article) {

     bindings.bind(String.class).first((StringPath path, String value) -> path.containsIgnoreCase(value));
  }
}

This only filters the first available value of a attribut. So in this case it only gives articles in category kitchen as Response. The second value of the category (sports) is ignored.

And now my Question: How can i get the articles of both catergories ignoring the case sensetive? What i need to change in my customize binding to achieve that?

Thank you very much

Answer 1

QuerydslBindings.TypeBinder#first uses a single value binding. You need to use QuerydslBindings.TypeBinder#all. This method operates on a multivalue binding.

I provided several examples of how to customize your bindings in this answer. Something like this should work for you:

@Override
default public void customize(QuerydslBindings bindings, QArticle article) {
    // using explicit path bindings
    bindings.bind(article.category).all((path, values) -> {
        BooleanBuilder predicate = new BooleanBuilder();
        // with a for loop
        for (String value : values) {
            predicate.or(path.containsIgnoreCase(value));
        }
    });

    // using a type binding
    bindings.bind(String.class).all((StringPath path, Collection<? extends String> values) -> {
        BooleanBuilder predicate = new BooleanBuilder();
        // oneliner with Java 8 forEach
        values.forEach( value -> predicate.or(path.containsIgnoreCase(value) );
    });

}

Answer 2

The correct bindings for your article.category property should be like this:

bindings.bind(article.category).all((path, value) -> {
    BooleanBuilder predicate = new BooleanBuilder();
    value.forEach(o -> predicate.or(path.equalsIgnoreCase(o)));
    return Optional.of(predicate);
});

If you don't need any manipulations of the parameters (like ignoring case) you can simplify it to that:

bindings.bind(article.category).all((path, value) -> Optional.of(path.in(value)));