Imagine I have optional search parameters that can be null.

Is there a more concise alternative for checking each of them explicitly before adding a jakarta.persistence.criteria.Predicate to some local List?

I mean this almost looks nice, fairly readable (though, Criteria is never really pretty):

import org.springframework.data.jpa.domain.Specification;

//...

    private static Specification buildSpecification(FindUserRequestDto userRequestDto) {
        return (root, query, criteriaBuilder) -> {
            var nameBeginsWith = criteriaBuilder.like(root.get("name"), userRequestDto.getName() + "%");
            var ageGreaterThan = criteriaBuilder.greaterThan(root.get("dateOfBirth"), userRequestDto.getDateOfBirth());
            var hasEmail = criteriaBuilder.equal(root.join("emailData").get("email"), userRequestDto.getEmail());
            var hasPhone = criteriaBuilder.equal(root.join("phoneData").get("phone"), userRequestDto.getPhone());
            return criteriaBuilder.and(nameBeginsWith, ageGreaterThan, hasEmail, hasPhone);

But if I introduce an explicit null check for each optional parameter, it'll get uglier, more verbose.

// like so
    private static Specification buildSpecification(FindUserRequestDto userRequestDto) {
        return (root, query, criteriaBuilder) -> {
            var nameBeginsWith = criteriaBuilder.like(root.get("name"), userRequestDto.getName() + "%");
            var bornAfter = criteriaBuilder.greaterThan(root.get("dateOfBirth"), userRequestDto.getDateOfBirth());
            var hasEmail = criteriaBuilder.equal(root.join("emailData").get("email"), userRequestDto.getEmail());
            var hasPhone = criteriaBuilder.equal(root.join("phoneData").get("phone"), userRequestDto.getPhone());

            List predicates = new ArrayList<>();
            if (userRequestDto.getName() != null) predicates.add(nameBeginsWith);
            if (userRequestDto.getDateOfBirth() != null) predicates.add(bornAfter);
            if (userRequestDto.getEmail() != null) predicates.add(hasEmail);
            if (userRequestDto.getPhone() != null) predicates.add(hasPhone);
            return criteriaBuilder.and(predicates.toArray(new jakarta.persistence.criteria.Predicate[0]));
        };
    }

You could argue it's a lost cause to try and make Criteria not verbose and ugly. But since I'm not very familiar with Criteria, I may be unaware of something. I wish Jakarta's Predicates had some or() method.

Here are my (simplified) entities:

import jakarta.persistence.CascadeType;
import jakarta.persistence.Column;
import jakarta.persistence.Entity;
import jakarta.persistence.FetchType;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.OneToMany;
import jakarta.persistence.Table;
import lombok.Getter;
import lombok.Setter;

import java.util.List;

@Entity
@Getter
@Setter
@Table(name = "\"user\"")
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    @OneToOne(mappedBy = "user")
    @OneToMany(mappedBy = "user", fetch = FetchType.EAGER,
            cascade = CascadeType.ALL, orphanRemoval = true)
    private List emailData;
}

import jakarta.persistence.Entity;
import jakarta.persistence.GeneratedValue;
import jakarta.persistence.GenerationType;
import jakarta.persistence.Id;
import jakarta.persistence.JoinColumn;
import jakarta.persistence.ManyToOne;
import jakarta.persistence.Table;
import lombok.Getter;
import lombok.Setter;

@Entity
@Getter
@Setter
@Table(name = "email_data")
public class EmailData {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @ManyToOne
    @JoinColumn(name = "user_id")
    private User user;
    private String email;
}