SpecificationComposition.java

/*
 * Copyright 2018-2025 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.data.jpa.domain;

import jakarta.persistence.criteria.CriteriaBuilder;
import jakarta.persistence.criteria.CriteriaDelete;
import jakarta.persistence.criteria.CriteriaQuery;
import jakarta.persistence.criteria.CriteriaUpdate;
import jakarta.persistence.criteria.From;
import jakarta.persistence.criteria.Predicate;
import jakarta.persistence.criteria.Root;

import java.io.Serializable;

import org.jspecify.annotations.Nullable;
import org.springframework.lang.Contract;

/**
 * Helper class to support specification compositions.
 *
 * @author Sebastian Staudt
 * @author Oliver Gierke
 * @author Jens Schauder
 * @author Mark Paluch
 * @since 2.2
 * @see Specification
 */
class SpecificationComposition {

	interface Combiner extends Serializable {
		@Nullable
		Predicate combine(CriteriaBuilder builder, Predicate lhs, Predicate rhs);
	}

	static <T> Specification<T> composed(@Nullable Specification<T> lhs, @Nullable Specification<T> rhs,
			Combiner combiner) {

		return (root, query, builder) -> {

			Predicate thisPredicate = toPredicate(lhs, root, query, builder);
			Predicate otherPredicate = toPredicate(rhs, root, query, builder);

			if (thisPredicate == null) {
				return otherPredicate;
			}

			return otherPredicate == null ? thisPredicate : combiner.combine(builder, thisPredicate, otherPredicate);
		};
	}

	private static <T> @Nullable Predicate toPredicate(@Nullable Specification<T> specification, Root<T> root,
			CriteriaQuery<?> query, CriteriaBuilder builder) {
		return specification == null ? null : specification.toPredicate(root, query, builder);
	}

	@Contract("_, _, !null -> new")
	@SuppressWarnings("NullAway")
	static <T> DeleteSpecification<T> composed(@Nullable DeleteSpecification<T> lhs, @Nullable DeleteSpecification<T> rhs,
			Combiner combiner) {

		return (root, query, builder) -> {

			Predicate thisPredicate = toPredicate(lhs, root, query, builder);
			Predicate otherPredicate = toPredicate(rhs, root, query, builder);

			if (thisPredicate == null) {
				return otherPredicate;
			}

			return otherPredicate == null ? thisPredicate : combiner.combine(builder, thisPredicate, otherPredicate);
		};
	}

	private static <T> @Nullable Predicate toPredicate(@Nullable DeleteSpecification<T> specification, Root<T> root,
			@Nullable CriteriaDelete<T> delete, CriteriaBuilder builder) {

		return specification == null || delete == null ? null : specification.toPredicate(root, delete, builder);
	}

	static <T> UpdateSpecification<T> composed(@Nullable UpdateSpecification<T> lhs, @Nullable UpdateSpecification<T> rhs,
			Combiner combiner) {

		return (root, query, builder) -> {

			Predicate thisPredicate = toPredicate(lhs, root, query, builder);
			Predicate otherPredicate = toPredicate(rhs, root, query, builder);

			if (thisPredicate == null) {
				return otherPredicate;
			}

			return otherPredicate == null ? thisPredicate : combiner.combine(builder, thisPredicate, otherPredicate);
		};
	}


	private static <T> @Nullable Predicate toPredicate(@Nullable UpdateSpecification<T> specification, Root<T> root,
			CriteriaUpdate<T> update, CriteriaBuilder builder) {
		return specification == null ? null : specification.toPredicate(root, update, builder);
	}

	static <T> PredicateSpecification<T> composed(PredicateSpecification<T> lhs, PredicateSpecification<T> rhs,
			Combiner combiner) {

		return (root, builder) -> {

			Predicate thisPredicate = toPredicate(lhs, root, builder);
			Predicate otherPredicate = toPredicate(rhs, root, builder);

			if (thisPredicate == null) {
				return otherPredicate;
			}

			return otherPredicate == null ? thisPredicate : combiner.combine(builder, thisPredicate, otherPredicate);
		};
	}

	private static <T> @Nullable Predicate toPredicate(@Nullable PredicateSpecification<T> specification, From<?, T> from,
			CriteriaBuilder builder) {
		return specification == null ? null : specification.toPredicate(from, builder);
	}

}