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more use of typesafe metamodel gen refs

This commit is contained in:
Gavin 2023-06-10 23:08:49 +02:00 committed by Christian Beikov
parent b6781bb655
commit acac3cfde5
1 changed files with 14 additions and 11 deletions
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25
documentation/src/main/asciidoc/introduction/Advanced.adoc
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@ -53,7 +53,7 @@ Any entity or collection which is affected by a filter must be annotated `@Filte
[source,java]
----
@Entity
@Filter(name = "ByRegion")
@Filter(name = example_.BY_REGION)
class User {
@Id String username;
@ -64,13 +64,15 @@ class User {
}
----
Here, as usual, `example_.BY_REGION` is generated by the Metamodel Generator, and is just a constant with the value `"ByRegion"`.
If the `@Filter` annotation does not explicitly specify a restriction, the default restriction given by the `@FilterDef` will be applied to the entity.
But an entity is free to override the default condition.
[source,java]
----
@Entity
@Filter(name = "ByRegion", condition = "name = :region")
@Filter(name = example_.FILTER_BY_REGION, condition = "name = :region")
class Region {
@Id String name;
@ -97,7 +99,7 @@ You should do this right at the _start_ of the session.
[source,java]
----
sessionFactory.inTransaction(session -> {
session.enableFilter("ByRegion")
session.enableFilter(example_.FILTER_BY_REGION)
.setParameter("region", "es")
.validate();
@ -812,11 +814,11 @@ class Book {
...
@ManyToOne(fetch = LAZY)
@FetchProfileOverride(profile = "EagerBook", mode = JOIN)
@FetchProfileOverride(profile = Book_.PROFILE_EAGER_BOOK, mode = JOIN)
Publisher publisher;
@ManyToMany
@FetchProfileOverride(profile = "EagerBook", mode = JOIN)
@FetchProfileOverride(profile = Book_.PROFILE_EAGER_BOOK, mode = JOIN)
Set<Author> authors;
...
@ -829,13 +831,15 @@ class Author {
...
@OneToOne
@FetchProfileOverride(profile = "EagerBook", mode = JOIN)
@FetchProfileOverride(profile = Book_.PROFILE_EAGER_BOOK, mode = JOIN)
Person person;
...
}
----
Here, once again, `Book_.PROFILE_EAGER_BOOK` is generated by the Metamodel Generator, and is just a constant with the value `"EagerBook"`.
For collections, we may even request subselect fetching:
[source,java]
@ -847,12 +851,13 @@ class Book {
...
@OneToOne
@FetchProfileOverride(profile = "EagerBook", mode = JOIN)
@FetchProfileOverride(profile = Book_.PROFILE_EAGER_BOOK, mode = JOIN)
Person person;
@ManyToMany
@FetchProfileOverride(profile = "EagerBook", mode = JOIN)
@FetchProfileOverride(profile = "BookWithAuthorsBySubselect", mode = SUBSELECT)
@FetchProfileOverride(profile = Book_.PROFILE_EAGER_BOOK, mode = JOIN)
@FetchProfileOverride(profile = Book_.BOOK_WITH_AUTHORS_BY_SUBSELECT,
mode = SUBSELECT)
Set<Author> authors;
...
@ -879,8 +884,6 @@ session.enableFetchProfile(Book_.PROFILE_EAGER_BOOK);
Book eagerBook = session.find(Book.class, bookId);
----
Here, once again, `BookQueries_.PROFILE_EAGER_BOOK` is generated by the Metamodel Generator, and is just a constant with the value `"EagerBook"`.
So why or when might we prefer named fetch profiles to entity graphs?
Well, it's really hard to say.
It's nice that this feature _exists_, and if you love it, that's great.