io.hypersistence.utils.hibernate.query.DistinctListTransformer Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of hypersistence-utils-hibernate-63 Show documentation

Utilities for Spring and Hibernate ORM 6.3, 6.4, and 6.5

There is a newer version: 3.8.3

Show newest version

package io.hypersistence.utils.hibernate.query;

import org.hibernate.query.ResultListTransformer;

import java.util.List;
import java.util.stream.Collectors;

/**
 * The {@link DistinctListTransformer} removes duplicates from the {@link List}
 * of elements that were transformed by the {@link org.hibernate.query.TupleTransformer}.
 * 
 * This is similar to the {@code DistinctResultTransformer} that was available in Hibernate 5.
 *
 * @author Vlad Mihalcea
 * @since 2.21.0
 */
public class DistinctListTransformer implements ResultListTransformer {

    public static final DistinctListTransformer INSTANCE = new DistinctListTransformer();

    /**
     * Deduplicates the provided List.
     *
     * @param collection collections to be deduplicated
     * @return deduplicated List
     */
    @Override
    public List transformList(List collection) {
        return (List) collection.stream().distinct().collect(Collectors.toList());
    }
}