Package jakarta.persistence.metamodel

package jakarta.persistence.metamodel

Defines the Jakarta Persistence Metamodel API, allowing runtime reflection on the managed types declared by a persistence unit.

Instances of metamodel types may be obtained either:

• via programmatic lookup using an instance of Metamodel obtained by calling EntityManagerFactory.getMetamodel(), or
• in a typesafe way, using members of the generated static metamodel classes.

The Metamodel API allows programmatic lookup, but is not in general typesafe.

SingularAttribute<Book,String> isbnAttribute =
        factory.getMetamodel()
            .entity(Book.class)
            .getId(String.class);

A static metamodel class is a class with static members providing direct type safe access to the metamodel objects representing the persistent members of a given managed class.

SingularAttribute<Book,String> isbnAttribute = Book_.isbn;

Since:

2.0

Related Packages

Package	Description
jakarta.persistence	Defines the core APIs for the management for persistence and object/relational mapping.
jakarta.persistence.criteria	Defines the Jakarta Persistence Criteria Query API.
jakarta.persistence.query	Defines annotations for expressing statically type safe queries by annotating query methods of a discoverable type or Jakarta Data repository.
jakarta.persistence.spi	Defines an SPI for integrating with the persistence provider and with the Jakarta EE platform.
jakarta.persistence.sql	Defines an API for the programmatic definition of SQL result set mappings to Java classes.

Class	Description
Attribute<X,Y>	Represents an attribute of a Java type.
Attribute.PersistentAttributeType
BasicType<X>	An instance of BasicType represents a basic type (possibly an enumerated, LOB, or temporal type).
Bindable<T>	An instances of the type Bindable represents an object or attribute type that can be bound into a Path.
Bindable.BindableType
BooleanAttribute<X>	Instances of the type BooleanAttribute represents persistent single-valued properties or fields of boolean type.
CollectionAttribute<X,E>	Instances of the type CollectionAttribute represent persistent Collection-valued attributes.
ComparableAttribute<X, C extends Comparable<? super C>>	Instances of the type ComparableAttribute represents persistent single-valued properties or fields of comparable type.
EmbeddableType<X>	An instance of EmbeddableType represents an embeddable type.
EntityType<X>	An instance of EntityType represents an entity type.
IdentifiableType<X>	An instance of the type IdentifiableType represents an entity or mapped superclass type.
ListAttribute<X,E>	Instances of the type ListAttribute represent persistent List-valued attributes.
ManagedType<X>	Instances of the type ManagedType represent entity, mapped superclass, and embeddable types.
MapAttribute<X,K,V>	Instances of the type MapAttribute represent persistent Map-valued attributes.
MappedSuperclassType<X>	An instance of the type MappedSuperclassType represents a mapped superclass type.
Metamodel	Provides access to the metamodel of persistent entities in the persistence unit.
NumericAttribute<X, N extends Number & Comparable<N>>	Instances of the type NumericAttribute represents persistent single-valued properties or fields of number type.
PluralAttribute<X,C,E>	Instances of the type PluralAttribute represent persistent collection-valued attributes.
PluralAttribute.CollectionType
SetAttribute<X,E>	Instances of the type SetAttribute represent persistent Set-valued attributes.
SingularAttribute<X,T>	Instances of the type SingularAttribute represents persistent single-valued properties or fields.
StaticMetamodel	The StaticMetamodel annotation specifies that the class is a metamodel class that represents the Java type designated by the StaticMetamodel.value() element.
TemporalAttribute<X, T extends Temporal & Comparable<? super T>>	Instances of the type TemporalAttribute represents persistent single-valued properties or fields of a temporal type.
TextAttribute<X>	Instances of the type TextAttribute represents persistent single-valued properties or fields of string type.
Type<X>	An instance of the type Type represents a persistent object or attribute type.
Type.PersistenceType