Visibility of SimpleJpaRepository.ExampleSpecification

[dabico]

Would it be possible to increase the visibility of SimpleJpaRepository.ExampleSpecification from private to protected?
I'm developing a custom repository that extends SimpleJpaRepository, and would like to reuse this inner class as opposed to copying it from the parent. The class in question:

spring-data-jpa/spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/support/SimpleJpaRepository.java

Lines 953 to 987 in 018c2ac

	/**
	* {@link Specification} that gives access to the {@link Predicate} instance representing the values contained in the
	* {@link Example}.
	*
	* @param <T>
	* @author Christoph Strobl
	* @since 1.10
	*/
	private static class ExampleSpecification<T> implements Specification<T> {
	private static final long serialVersionUID = 1L;
	private final Example<T> example;
	private final EscapeCharacter escapeCharacter;
	/**
	* Creates new {@link ExampleSpecification}.
	*
	* @param example the example to base the specification of. Must not be {@literal null}.
	* @param escapeCharacter the escape character to use for like expressions. Must not be {@literal null}.
	*/
	ExampleSpecification(Example<T> example, EscapeCharacter escapeCharacter) {
	Assert.notNull(example, "Example must not be null");
	Assert.notNull(escapeCharacter, "EscapeCharacter must not be null");
	this.example = example;
	this.escapeCharacter = escapeCharacter;
	}
	@Override
	public Predicate toPredicate(Root<T> root, CriteriaQuery<?> query, CriteriaBuilder cb) {
	return QueryByExamplePredicateBuilder.getPredicate(root, cb, example, escapeCharacter);
	}
	}

[gregturn]

Fundamentally speaking, ExampleSpecification is an implementation detail to provide support for Query by Example.

I'd really to understand the use case you are attempting to solve that begs you to make changes and alterations to ExampleSpecification.

[dabico]

Hi @gregturn

In short, I wanted to create an extension to the Specification and Example query APIs to support Stream.

Here are the methods and signatures:
https://github.com/seart-group/DL4SE/blob/274dbefd77f16b00cdace01d87a399a8308c7915/dl4se-server/src/main/java/ch/usi/si/seart/server/repository/support/JpaStreamExecutor.java

Here is the custom repository implementation:
https://github.com/seart-group/DL4SE/blob/274dbefd77f16b00cdace01d87a399a8308c7915/dl4se-server/src/main/java/ch/usi/si/seart/server/repository/support/ExtendedJpaRepositoryImpl.java

I would not be making changes to the class itself, in fact, it can be final for all I care, so long as its visible and can be instantiated from this custom SimpleJpaRepository extension.

[mp911de]

Have you seen that you have all of this flexibility if you use the fluent findBy(Specification, q -> q.stream()) or findBy(Example, q -> q.stream()) API?

[dabico]

Have you seen that you have all of this flexibility if you use the fluent findBy(Specification, q -> q.stream()) or findBy(Example, q -> q.stream()) API?

HI @mp911de

I was not aware of this API, when was it introduced? I'm still on SB 2.7, and I don't think our organization will migrate to 3.X in the near future.

[mp911de]

It has been introduced with version 3.0. Spring Data JPA 2.7 has reached its OSS EOL by now (Nov 2023) and we will ship only one final OSS release.
We generally avoid updates to API that has been released as changes to API that is available for quite a while asks for trouble.

Given that update, I'm closing the ticket.