/*
* Copyright (c) 2008, 2009 Sun Microsystems. All rights reserved.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Linda DeMichiel - Java Persistence 2.0 - Version 2.0 (October 1, 2009)
* Specification available from http://jcp.org/en/jsr/detail?id=317
*/
// $Id: Subquery.java 20957 2011-06-13 09:58:51Z stliu $
package javax.persistence.criteria;
import java.util.List;
import java.util.Set;
/**
* The <code>Subquery</code> interface defines functionality that is
* specific to subqueries.
*
* A subquery has an expression as its selection item.
*
* @param <T> the type of the selection item.
* @since Java Persistence 2.0
*/
public interface Subquery<T> extends AbstractQuery<T>, Expression<T> {
/**
* Specify the item that is to be returned as the subquery
* result.
* Replaces the previously specified selection, if any.
*
* @param expression expression specifying the item that
* is to be returned as the subquery result
*
* @return the modified subquery
*/
Subquery<T> select(Expression<T> expression);
/**
* Modify the subquery to restrict the 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 <code>AbstractQuery</code> method.
*
* @param restriction a simple or compound boolean expression
*
* @return the modified subquery
*/
Subquery<T> where(Expression<Boolean> restriction);
/**
* Modify the subquery to restrict the 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 <code>AbstractQuery</code> method.
*
* @param restrictions zero or more restriction predicates
*
* @return the modified subquery
*/
Subquery<T> where(Predicate... restrictions);
/**
* Specify the expressions that are used to form groups over
* the subquery 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 <code>AbstractQuery</code> method.
*
* @param grouping zero or more grouping expressions
*
* @return the modified subquery
*/
Subquery<T> groupBy(Expression<?>... grouping);
/**
* Specify the expressions that are used to form groups over
* the subquery 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 <code>AbstractQuery</code> method.
*
* @param grouping list of zero or more grouping expressions
*
* @return the modified subquery
*/
Subquery<T> groupBy(List<Expression<?>> grouping);
/**
* Specify a restriction over the groups of the subquery.
* Replaces the previous having restriction(s), if any.
* This method only overrides the return type of the
* corresponding <code>AbstractQuery</code> method.
*
* @param restriction a simple or compound boolean expression
*
* @return the modified subquery
*/
Subquery<T> having(Expression<Boolean> restriction);
/**
* Specify restrictions over the groups of the subquery
* 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 <code>AbstractQuery</code> method.
*
* @param restrictions zero or more restriction predicates
*
* @return the modified subquery
*/
Subquery<T> having(Predicate... restrictions);
/**
* 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 <code>AbstractQuery</code> method.
*
* @param distinct boolean value specifying whether duplicate
* results must be eliminated from the subquery result or
* whether they must be retained
*
* @return the modified subquery.
*/
Subquery<T> distinct(boolean distinct);
/**
* Create a subquery root correlated to a root of the
* enclosing query.
*
* @param parentRoot a root of the containing query
*
* @return subquery root
*/
<Y> Root<Y> correlate(Root<Y> parentRoot);
/**
* Create a subquery join object correlated to a join object
* of the enclosing query.
*
* @param parentJoin join object of the containing query
*
* @return subquery join
*/
<X, Y> Join<X, Y> correlate(Join<X, Y> parentJoin);
/**
* Create a subquery collection join object correlated to a
* collection join object of the enclosing query.
*
* @param parentCollection join object of the containing query
*
* @return subquery join
*/
<X, Y> CollectionJoin<X, Y> correlate(CollectionJoin<X, Y> parentCollection);
/**
* Create a subquery set join object correlated to a set join
* object of the enclosing query.
*
* @param parentSet join object of the containing query
*
* @return subquery join
*/
<X, Y> SetJoin<X, Y> correlate(SetJoin<X, Y> parentSet);
/**
* Create a subquery list join object correlated to a list join
* object of the enclosing query.
*
* @param parentList join object of the containing query
*
* @return subquery join
*/
<X, Y> ListJoin<X, Y> correlate(ListJoin<X, Y> parentList);
/**
* Create a subquery map join object correlated to a map join
* object of the enclosing query.
*
* @param parentMap join object of the containing query
*
* @return subquery join
*/
<X, K, V> MapJoin<X, K, V> correlate(MapJoin<X, K, V> parentMap);
/**
* Return the query of which this is a subquery.
*
* @return the enclosing query or subquery
*/
AbstractQuery<?> getParent();
/**
* Return the selection expression.
*
* @return the item to be returned in the subquery result
*/
Expression<T> getSelection();
/**
* Return the correlated joins of the subquery.
* Returns empty set if the subquery has no correlated
* joins.
* Modifications to the set do not affect the query.
*
* @return the correlated joins of the subquery
*/
Set<Join<?, ?>> getCorrelatedJoins();
}