2706 words

javax.persistence.criteria.CriteriaQuery - JPA interface

javax.persistence.criteria
Interface CriteriaQuery<T>

Superinterfaces:
AbstractQuery<T>
The CriteriaQuery interface defines functionality that is specific to top-level queries.
Since:
JPA 2.0
Learn how to define queries using the criteria API in Chapter 4 of the ObjectDB/JPA manual.
AbstractQuery<T> distinct(boolean distinct)
Specify whether duplicate query results will be eliminated.
Specify whether duplicate query results will be eliminated. A true value will cause duplicates to be eliminated. A false value will cause duplicates to be retained. If distinct has not been specified, duplicate results must be retained.
Parameters:
distinct - boolean value specifying whether duplicate results must be eliminated from the query result or whether they must be retained
Returns:
the modified query
Since:
JPA 2.0
CriteriaQuery<T> distinct(boolean distinct)
Specify whether duplicate query results will be eliminated.
Specify whether duplicate query results will be eliminated. A true value will cause duplicates to be eliminated. A false value will cause duplicates to be retained. If distinct has not been specified, duplicate results must be retained. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
distinct - boolean value specifying whether duplicate results must be eliminated from the query result or whether they must be retained
Returns:
the modified query.
Since:
JPA 2.0
Root<X> from(Class<X> entityClass)
Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.
Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.
Parameters:
entityClass - the entity class
Returns:
query root corresponding to the given entity
Since:
JPA 2.0
Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.
Create and add a query root corresponding to the given entity, forming a cartesian product with any existing roots.
Parameters:
entity - metamodel entity representing the entity of type X
Returns:
query root corresponding to the given entity
Since:
JPA 2.0
Return a list of the grouping expressions.
Return a list of the grouping expressions. Returns empty list if no grouping expressions have been specified. Modifications to the list do not affect the query.
Returns:
the list of grouping expressions
Since:
JPA 2.0
Return the predicate that corresponds to the restriction(s) over the grouping items, or null if no restrictions have been specified.
Return the predicate that corresponds to the restriction(s) over the grouping items, or null if no restrictions have been specified.
Returns:
having clause predicate
Since:
JPA 2.0
Return the ordering expressions in order of precedence.
Return the ordering expressions in order of precedence. Returns empty list if no ordering expressions have been specified. Modifications to the list do not affect the query.
Returns:
the list of ordering expressions
Since:
JPA 2.0
Return the parameters of the query.
Return the parameters of the query. Returns empty set if there are no parameters. Modifications to the set do not affect the query.
Returns:
the query parameters
Since:
JPA 2.0
Return the predicate that corresponds to the where clause restriction(s), or null if no restrictions have been specified.
Return the predicate that corresponds to the where clause restriction(s), or null if no restrictions have been specified.
Returns:
where clause predicate
Since:
JPA 2.0
Class<T> getResultType()
Return the result type of the query or subquery.
Return the result type of the query or subquery. If a result type was specified as an argument to the createQuery or subquery method, that type will be returned. If the query was created using the createTupleQuery method, the result type is Tuple. Otherwise, the result type is Object.
Returns:
result type
Since:
JPA 2.0
Return the query roots.
Return the query roots. These are the roots that have been defined for the CriteriaQuery or Subquery itself, including any subquery roots defined as a result of correlation. Returns empty set if no roots have been defined. Modifications to the set do not affect the query.
Returns:
the set of query roots
Since:
JPA 2.0
Return the selection of the query, or null if no selection has been set.
Return the selection of the query, or null if no selection has been set.
Returns:
selection item
Since:
JPA 2.0
Specify the expressions that are used to form groups over the query results.
Specify the expressions that are used to form groups over the query results. Replaces the previous specified grouping expressions, if any. If no grouping expressions are specified, any previously added grouping expressions are simply removed.
Parameters:
grouping - list of zero or more grouping expressions
Returns:
the modified query
Since:
JPA 2.0
Specify the expressions that are used to form groups over the query results.
Specify the expressions that are used to form groups over the query results. Replaces the previous specified grouping expressions, if any. If no grouping expressions are specified, any previously added grouping expressions are simply removed. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
grouping - list of zero or more grouping expressions
Returns:
the modified query
Since:
JPA 2.0
Specify the expressions that are used to form groups over the query results.
Specify the expressions that are used to form groups over the query results. Replaces the previous specified grouping expressions, if any. If no grouping expressions are specified, any previously added grouping expressions are simply removed.
Parameters:
grouping - zero or more grouping expressions
Returns:
the modified query
Since:
JPA 2.0
Specify the expressions that are used to form groups over the query results.
Specify the expressions that are used to form groups over the query results. Replaces the previous specified grouping expressions, if any. If no grouping expressions are specified, any previously added grouping expressions are simply removed. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
grouping - zero or more grouping expressions
Returns:
the modified query
Since:
JPA 2.0
Specify restrictions over the groups of the query according the conjunction of the specified restriction predicates.
Specify restrictions over the groups of the query according the conjunction of the specified restriction predicates. Replaces the previously having added restriction(s), if any. If no restrictions are specified, any previously added restrictions are simply removed.
Parameters:
restrictions - zero or more restriction predicates
Returns:
the modified query
Since:
JPA 2.0
Specify restrictions over the groups of the query according the conjunction of the specified restriction predicates.
Specify restrictions over the groups of the query according the conjunction of the specified restriction predicates. Replaces the previously added having restriction(s), if any. If no restrictions are specified, any previously added restrictions are simply removed. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
restrictions - zero or more restriction predicates
Returns:
the modified query
Since:
JPA 2.0
Specify a restriction over the groups of the query.
Specify a restriction over the groups of the query. Replaces the previous having restriction(s), if any.
Parameters:
restriction - a simple or compound boolean expression
Returns:
the modified query
Since:
JPA 2.0
Specify a restriction over the groups of the query.
Specify a restriction over the groups of the query. Replaces the previous having restriction(s), if any. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
restriction - a simple or compound boolean expression
Returns:
the modified query
Since:
JPA 2.0
boolean isDistinct()
Return whether duplicate query results must be eliminated or retained.
Return whether duplicate query results must be eliminated or retained.
Returns:
boolean indicating whether duplicate query results must be eliminated
Since:
JPA 2.0
Specify the selection items that are to be returned in the query result.
Specify the selection items that are to be returned in the query result. Replaces the previously specified selection(s), if any.

The type of the result of the query execution depends on the specification of the type of the criteria query object created as well as the argument to the multiselect method. An element of the list passed to the multiselect method must not be a tuple- or array-valued compound selection item.

The semantics of this method are as follows:

  • If the type of the criteria query is CriteriaQuery (i.e., a criteria query object created by either the createTupleQuery method or by passing a Tuple class argument to the createQuery method), a Tuple object corresponding to the elements of the list passed to the multiselect method, in the specified order, will be instantiated and returned for each row that results from the query execution.
  • If the type of the criteria query is CriteriaQuery for some user-defined class X (i.e., a criteria query object created by passing a X class argument to the createQuery method), the elements of the list passed to the multiselect method will be passed to the X constructor and an instance of type X will be returned for each row.
  • If the type of the criteria query is CriteriaQuery for some class X, an instance of type X[] will be returned for each row. The elements of the array will correspond to the elements of the list passed to the multiselect method, in the specified order.
  • If the type of the criteria query is CriteriaQuery or if the criteria query was created without specifying a type, and the list passed to the multiselect method contains only a single element, an instance of type Object will be returned for each row.
  • If the type of the criteria query is CriteriaQuery or if the criteria query was created without specifying a type, and the list passed to the multiselect method contains more than one element, an instance of type Object[] will be instantiated and returned for each row. The elements of the array will correspond to the elements of the list passed to the multiselect method, in the specified order.

Parameters:
selectionList - list of selection items corresponding to the results to be returned by the query
Returns:
the modified query
Throws:
IllegalArgumentException - if a selection item is not valid or if more than one selection item has the same assigned alias
Since:
JPA 2.0
Specify the selection items that are to be returned in the query result.
Specify the selection items that are to be returned in the query result. Replaces the previously specified selection(s), if any. The type of the result of the query execution depends on the specification of the type of the criteria query object created as well as the arguments to the multiselect method.

An argument to the multiselect method must not be a tuple- or array-valued compound selection item.

The semantics of this method are as follows:

  • If the type of the criteria query is CriteriaQuery (i.e., a criteria query object created by either the createTupleQuery method or by passing a Tuple class argument to the createQuery method), a Tuple object corresponding to the arguments of the multiselect method, in the specified order, will be instantiated and returned for each row that results from the query execution.
  • If the type of the criteria query is CriteriaQuery for some user-defined class X (i.e., a criteria query object created by passing a X class argument to the createQuery method), the arguments to the multiselect method will be passed to the X constructor and an instance of type X will be returned for each row.
  • If the type of the criteria query is CriteriaQuery for some class X, an instance of type X[] will be returned for each row. The elements of the array will correspond to the arguments of the multiselect method, in the specified order.
  • If the type of the criteria query is CriteriaQuery or if the criteria query was created without specifying a type, and only a single argument is passed to the multiselect method, an instance of type Object will be returned for each row.
  • If the type of the criteria query is CriteriaQuery or if the criteria query was created without specifying a type, and more than one argument is passed to the multiselect method, an instance of type Object[] will be instantiated and returned for each row. The elements of the array will correspond to the arguments to the multiselect method, in the specified order.

Parameters:
selections - selection items corresponding to the results to be returned by the query
Returns:
the modified query
Throws:
IllegalArgumentException - if a selection item is not valid or if more than one selection item has the same assigned alias
Since:
JPA 2.0
Specify the ordering expressions that are used to order the query results.
Specify the ordering expressions that are used to order the query results. Replaces the previous ordering expressions, if any. If no ordering expressions are specified, the previous ordering, if any, is simply removed, and results will be returned in no particular order. The order of the ordering expressions in the list determines the precedence, whereby the first element in the list has highest precedence.
Parameters:
o - list of zero or more ordering expressions
Returns:
the modified query
Since:
JPA 2.0
Specify the ordering expressions that are used to order the query results.
Specify the ordering expressions that are used to order the query results. Replaces the previous ordering expressions, if any. If no ordering expressions are specified, the previous ordering, if any, is simply removed, and results will be returned in no particular order. The left-to-right sequence of the ordering expressions determines the precedence, whereby the leftmost has highest precedence.
Parameters:
o - zero or more ordering expressions
Returns:
the modified query
Since:
JPA 2.0
Specify the item that is to be returned in the query result.
Specify the item that is to be returned in the query result. Replaces the previously specified selection(s), if any.

Note: Applications using the string-based API may need to specify the type of the select item when it results from a get or join operation and the query result type is specified.

     For example:
 
     CriteriaQuery<String> q = cb.createQuery(String.class);
     Root<Order> order = q.from(Order.class);
     q.select(order.get("shippingAddress").<String>get("state"));
 
     CriteriaQuery<Product> q2 = cb.createQuery(Product.class);
     q2.select(q2.from(Order.class)
                 .join("items")
                 .<Item,Product>join("product"));

Parameters:
selection - selection specifying the item that is to be returned in the query result
Returns:
the modified query
Throws:
IllegalArgumentException - if the selection is a compound selection and more than one selection item has the same assigned alias
Since:
JPA 2.0
Subquery<U> subquery(Class<U> type)
Create a subquery of the query.
Create a subquery of the query.
Parameters:
type - the subquery result type
Returns:
subquery
Since:
JPA 2.0
Modify the query to restrict the query results according to the conjunction of the specified restriction predicates.
Modify the query to restrict the query results according to the conjunction of the specified restriction predicates. Replaces the previously added restriction(s), if any. If no restrictions are specified, any previously added restrictions are simply removed.
Parameters:
restrictions - zero or more restriction predicates
Returns:
the modified query
Since:
JPA 2.0
Modify the query to restrict the query result according to the conjunction of the specified restriction predicates.
Modify the query to restrict the query result according to the conjunction of the specified restriction predicates. Replaces the previously added restriction(s), if any. If no restrictions are specified, any previously added restrictions are simply removed. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
restrictions - zero or more restriction predicates
Returns:
the modified query
Since:
JPA 2.0
Modify the query to restrict the query results according to the specified boolean expression.
Modify the query to restrict the query results according to the specified boolean expression. Replaces the previously added restriction(s), if any.
Parameters:
restriction - a simple or compound boolean expression
Returns:
the modified query
Since:
JPA 2.0
Modify the query to restrict the query result according to the specified boolean expression.
Modify the query to restrict the query result according to the specified boolean expression. Replaces the previously added restriction(s), if any. This method only overrides the return type of the corresponding AbstractQuery method.
Parameters:
restriction - a simple or compound boolean expression
Returns:
the modified query
Since:
JPA 2.0

This documentation page is derived (with some adjustments) from the open source JPA 2 RI (EclipseLink)
and is available under the terms of the Eclipse Public License, v. 1.0 and Eclipse Distribution License, v. 1.0.
Object Relational Mapping (ORM) JPA 2 providers include Hibernate, EclipseLink, TopLink, OpenJPA and DataNucleus.
Object DB is not an ORM JPA implementation but an Object Database for Java with built in JPA 2 support.