| /* |
| * Copyright (c) 2011, 2021 Oracle and/or its affiliates. All rights reserved. |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Public License v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // Contributors: |
| // Oracle - initial API and implementation |
| // |
| package org.eclipse.persistence.jpa.jpql.tools.model.query; |
| |
| import org.eclipse.persistence.jpa.jpql.parser.AbstractSelectClause; |
| |
| /** |
| * This state object represents the abstract definition of a <code><b>SELECT</b></code> clause, |
| * which is either the <code>SELECT</code> clause of the top-level query or of a subquery. |
| * |
| * @see AbstractSelectStatementStateObject |
| * @see SelectClauseStateObject |
| * |
| * @see AbstractSelectClause |
| * |
| * @version 2.4 |
| * @since 2.4 |
| * @author Pascal Filion |
| */ |
| @SuppressWarnings("nls") |
| public abstract class AbstractSelectClauseStateObject extends AbstractStateObject { |
| |
| /** |
| * Determines whether the <code><b>DISTINCT</b></code> keyword is part of the query, which is |
| * used to return only distinct (different) values. |
| */ |
| private boolean distinct; |
| |
| /** |
| * Notifies the distinct property has changed. |
| */ |
| public static final String DISTINCT_PROPERTY = "distinct"; |
| |
| /** |
| * Creates a new <code>AbstractSelectClauseStateObject</code>. |
| * |
| * @param parent The parent of this state object, which cannot be <code>null</code> |
| * @exception NullPointerException The given parent cannot be <code>null</code> |
| */ |
| protected AbstractSelectClauseStateObject(AbstractSelectStatementStateObject parent) { |
| super(parent); |
| } |
| |
| @Override |
| public AbstractSelectClause getExpression() { |
| return (AbstractSelectClause) super.getExpression(); |
| } |
| |
| /** |
| * Returns the {@link AbstractFromClauseStateObject} representing the <b>FROM</b> clause. |
| * |
| * @return The state object representing the <b>FROM</b> clause |
| */ |
| public AbstractFromClauseStateObject getFromClause() { |
| return getParent().getFromClause(); |
| } |
| |
| @Override |
| public AbstractSelectStatementStateObject getParent() { |
| return (AbstractSelectStatementStateObject) super.getParent(); |
| } |
| |
| /** |
| * Gets whether the <code>DISTINCT</code> keyword is part of the query, which is used to |
| * return only distinct (different) values |
| */ |
| public boolean hasDistinct() { |
| return distinct; |
| } |
| |
| /** |
| * Determines whether this <code><b>SELECT</b></code> clause has a select item defined (only one |
| * can be set for a subquery's <code><b>SELECT</b></code> clause and many for a top-level query). |
| * |
| * @return <code>true</code> if this state object has children; <code>false</code> otherwise |
| */ |
| public abstract boolean hasSelectItem(); |
| |
| @Override |
| public boolean isEquivalent(StateObject stateObject) { |
| |
| if (super.isEquivalent(stateObject)) { |
| AbstractSelectClauseStateObject select = (AbstractSelectClauseStateObject) stateObject; |
| return distinct && select.distinct; |
| } |
| |
| return false; |
| } |
| |
| /** |
| * Parses the given JPQL fragment and create the select item. For the top-level query, the |
| * fragment can contain several select items but for a subquery, it can represent only one. |
| * |
| * @param jpqlFragment The portion of the query representing one or several select items |
| */ |
| public abstract void parse(String jpqlFragment); |
| |
| /** |
| * Sets whether the <code>DISTINCT</code> keyword should be part of the query, which is used to |
| * return only distinct (different) values |
| * |
| * @param distinct <code>true</code> to add <code>DISTINCT</code> to the query in order to have |
| * distinct values; <code>false</code> if it is not required |
| */ |
| public void setDistinct(boolean distinct) { |
| boolean oldDistinct = this.distinct; |
| this.distinct = distinct; |
| firePropertyChanged(DISTINCT_PROPERTY, oldDistinct, distinct); |
| } |
| |
| /** |
| * Changes the state of the <code><b>DISTINCT</b></code> identifier; either adds it if it's not |
| * present or removes it if it's present. |
| */ |
| public void toggleDistinct() { |
| setDistinct(!hasDistinct()); |
| } |
| } |