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/*
 * 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: AbstractQuery.java 20957 2011-06-13 09:58:51Z stliu $

package javax.persistence.criteria;

import java.util.List;
import java.util.Set;

import javax.persistence.metamodel.EntityType;

/**
 * The AbstractQuery interface defines functionality that is common
 * to both top-level queries and subqueries.
 * It is not intended to be used directly in query construction.
 *
 * 

All queries must have: * a set of root entities (which may in turn own joins). *

All queries may have: * a conjunction of restrictions. * * @param the type of the result * @since Java Persistence 2.0 */ public interface AbstractQuery { /** * Create and add a query root corresponding to the given entity, * forming a cartesian product with any existing roots. * * @param entityClass the entity class * * @return query root corresponding to the given entity */ Root from(Class entityClass); /** * Create and add a query root corresponding to the given entity, * forming a cartesian product with any existing roots. * * @param entity metamodel entity representing the entity * of type X * * @return query root corresponding to the given entity */ Root from(EntityType entity); /** * Modify the query to restrict the query results according * to the specified boolean expression. * Replaces the previously added restriction(s), if any. * * @param restriction a simple or compound boolean expression * * @return the modified query */ AbstractQuery where(Expression restriction); /** * 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. * * @param restrictions zero or more restriction predicates * * @return the modified query */ AbstractQuery where(Predicate... restrictions); /** * 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. * * @param grouping zero or more grouping expressions * * @return the modified query */ AbstractQuery groupBy(Expression... grouping); /** * 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. * * @param grouping list of zero or more grouping expressions * * @return the modified query */ AbstractQuery groupBy(List> grouping); /** * Specify a restriction over the groups of the query. * Replaces the previous having restriction(s), if any. * * @param restriction a simple or compound boolean expression * * @return the modified query */ AbstractQuery having(Expression restriction); /** * 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. * * @param restrictions zero or more restriction predicates * * @return the modified query */ AbstractQuery 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. * * @param distinct boolean value specifying whether duplicate * results must be eliminated from the query result or * whether they must be retained * * @return the modified query */ AbstractQuery distinct(boolean distinct); /** * Create a subquery of the query. * * @param type the subquery result type * * @return subquery */ Subquery subquery(Class type); /** * 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. * * @return the set of query roots */ Set> getRoots(); /** * Return the selection of the query, or null if no selection * has been set. * * @return selection item */ Selection getSelection(); /** * Return the predicate that corresponds to the where clause * restriction(s), or null if no restrictions have been * specified. * * @return where clause predicate */ Predicate getRestriction(); /** * 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. * * @return the list of grouping expressions */ List> getGroupList(); /** * Return the predicate that corresponds to the restriction(s) * over the grouping items, or null if no restrictions have * been specified. * * @return having clause predicate */ Predicate getGroupRestriction(); /** * Return whether duplicate query results must be eliminated or * retained. * * @return boolean indicating whether duplicate query results * must be eliminated */ boolean isDistinct(); /** * 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. * * @return result type */ Class getResultType(); }