Jakarta Persistence (JPA) Interface

jakarta.persistence.criteria.Expression<T>

Type Parameters:
<T> - the type of the expression
Super Interfaces:
Selection<X>, TupleElement<X>
Type for query expressions.
Since:
Jakarta Persistence (JPA) 2.0
The JPA Query Expressions (JPQL / Criteria) article explains how to use Expression.

Public Instance Methods

Selection<X> alias(String name)
Assigns an alias to the selection item.
Once assigned, an alias cannot be changed or reassigned. Returns the same selection item.
Inherited from Selection<X>
Parameters:
name - alias
Returns:
selection item.
Since:
Jakarta Persistence (JPA) 1.0
Expression<X> as(Class<X> type)
Perform a typecast upon the expression, returning a new expression object.
Unlike cast, this method does not cause type conversion: the runtime type is not changed.

Warning: may result in a runtime failure.

Parameters:
type - intended type of the expression
Returns:
new expression of the given type.
See Also:
Since:
Jakarta Persistence (JPA) 1.0
Expression<X> cast(Class<X> type)
Cast this expression to the specified type, returning a new expression object.
Unlike as, this method does result in a runtime type conversion.

Providers are required to support casting scalar expressions to String, and String expressions to Integer, Long, Float, and Double. Support for typecasts between other basic types is not required.

Parameters:
type - a basic type
Returns:
a scalar expression of the given basic type.
Since:
Jakarta Persistence (JPA) 3.2
Predicate equalTo(Expression<?> value)
Create a predicate to test whether the expression is equal to the argument.
Parameters:
value - expression to be tested against
Returns:
predicate testing for equality.
Since:
Jakarta Persistence (JPA) 3.2
Predicate equalTo(Object value)
Create a predicate to test whether the expression is equal to the argument.
Parameters:
value - value to be tested against
Returns:
predicate testing for equality.
Since:
Jakarta Persistence (JPA) 3.2
String getAlias()
Return the alias assigned to the tuple element or null, if no alias has been assigned.
Inherited from TupleElement<X>
Returns:
alias.
Since:
Jakarta Persistence (JPA) 1.0
List<Selection<?>> getCompoundSelectionItems()
Return the selection items composing a compound selection.
Modifications to the list do not affect the query.
Inherited from Selection<X>
Returns:
list of selection items.
Throws:
IllegalStateException - if selection is not a compound selection.
Since:
Jakarta Persistence (JPA) 1.0
Class<? extends X> getJavaType()
Return the Java type of the tuple element.
Inherited from TupleElement<X>
Returns:
the Java type of the tuple element.
Since:
Jakarta Persistence (JPA) 1.0
Predicate in(Object... values)
Create a predicate to test whether the expression is a member of the argument list.
Parameters:
values - values to be tested against
Returns:
predicate testing for membership.
Since:
Jakarta Persistence (JPA) 1.0
Predicate in(Expression<?>... values)
Create a predicate to test whether the expression is a member of the argument list.
Parameters:
values - expressions to be tested against
Returns:
predicate testing for membership.
Since:
Jakarta Persistence (JPA) 1.0
Predicate in(Collection<?> values)
Create a predicate to test whether the expression is a member of the collection.
Parameters:
values - collection of values to be tested against
Returns:
predicate testing for membership.
Since:
Jakarta Persistence (JPA) 1.0
Predicate in(Expression<Collection<?>> values)
Create a predicate to test whether the expression is a member of the collection.
Parameters:
values - expression corresponding to collection to be tested against
Returns:
predicate testing for membership.
Since:
Jakarta Persistence (JPA) 1.0
boolean isCompoundSelection()
Whether the selection item is a compound selection.
Inherited from Selection<X>
Returns:
boolean indicating whether the selection is a compound selection.
Since:
Jakarta Persistence (JPA) 1.0
Predicate isNotNull()
Create a predicate to test whether the expression is not null.
Returns:
predicate testing whether the expression is not null.
Since:
Jakarta Persistence (JPA) 1.0
Predicate isNull()
Create a predicate to test whether the expression is null.
Returns:
predicate testing whether the expression is null.
Since:
Jakarta Persistence (JPA) 1.0
Predicate notEqualTo(Expression<?> value)
Create a predicate to test whether the expression is unequal to the argument.
Parameters:
value - expression to be tested against
Returns:
predicate testing for inequality.
Since:
Jakarta Persistence (JPA) 3.2
Predicate notEqualTo(Object value)
Create a predicate to test whether the expression is unequal to the argument.
Parameters:
value - value to be tested against
Returns:
predicate testing for inequality.
Since:
Jakarta Persistence (JPA) 3.2