| /* |
| * Copyright (c) 2006, 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.parser; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.List; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * The <b>SELECT</b> clause denotes the query result. More than one value may be returned from the |
| * <b>SELECT</b> clause of a query. The <b>SELECT</b> clause may contain one or more of the |
| * following elements: a single range variable or identification variable that ranges over an entity |
| * abstract schema type, a single-valued path expression, an aggregate select expression, a |
| * constructor expression. |
| * <p> |
| * The <b>DISTINCT</b> keyword is used to specify that duplicate values must be eliminated from the |
| * query result. If <b>DISTINCT</b> is not specified, duplicate values are not eliminated. |
| * Stand-alone identification variables in the <b>SELECT</b> clause may optionally be qualified by |
| * the <b>OBJECT</b> operator. The <b>SELECT</b> clause must not use the <b>OBJECT</b> operator to |
| * qualify path expressions. |
| * |
| * @see SelectClause |
| * @see SimpleSelectClause |
| * |
| * @version 2.5 |
| * @since 2.3 |
| * @author Pascal Filion |
| */ |
| public abstract class AbstractSelectClause extends AbstractExpression { |
| |
| /** |
| * The actual <b>DISTINCT</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String distinctIdentifier; |
| |
| /** |
| * Determines whether a whitespace was parsed after the <b>DISTINCT</b>. |
| */ |
| private boolean hasSpaceAfterDistinct; |
| |
| /** |
| * Determines whether a whitespace was parsed after the <b>SELECT</b>. |
| */ |
| private boolean hasSpaceAfterSelect; |
| |
| /** |
| * The actual identifier found in the string representation of the JPQL query. |
| */ |
| private String identifier; |
| |
| /** |
| * The actual expression of this select clause. |
| */ |
| private AbstractExpression selectExpression; |
| |
| /** |
| * Creates a new <code>SelectClause</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| protected AbstractSelectClause(AbstractExpression parent) { |
| super(parent, SELECT); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getSelectExpression().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getSelectExpression()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // 'SELECT' |
| children.add(buildStringExpression(SELECT)); |
| |
| if (hasSpaceAfterSelect) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'DISTINCT' |
| if (distinctIdentifier != null) { |
| children.add(buildStringExpression(DISTINCT)); |
| } |
| |
| if (hasSpaceAfterDistinct) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Select expression |
| if (selectExpression != null) { |
| children.add(selectExpression); |
| } |
| } |
| |
| /** |
| * Creates a new {@link CollectionExpression} that will wrap the single select item. |
| * |
| * @return The single select item represented by a temporary collection |
| */ |
| public CollectionExpression buildCollectionExpression() { |
| |
| List<AbstractExpression> children = new ArrayList<AbstractExpression>(1); |
| children.add((AbstractExpression) getSelectExpression()); |
| |
| List<Boolean> commas = new ArrayList<Boolean>(1); |
| commas.add(Boolean.FALSE); |
| |
| List<Boolean> spaces = new ArrayList<Boolean>(1); |
| spaces.add(Boolean.FALSE); |
| |
| return new CollectionExpression(this, children, commas, spaces, true); |
| } |
| |
| @Override |
| public JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((selectExpression != null) && selectExpression.isAncestor(expression)) { |
| return getQueryBNF(getSelectItemQueryBNFId()); |
| } |
| |
| return super.findQueryBNF(expression); |
| } |
| |
| /** |
| * Returns the actual <b>DISTINCT</b> identifier found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <b>DISTINCT</b> identifier that was actually parsed, or an empty string if it was |
| * not parsed |
| * @since 2.4 |
| */ |
| public final String getActualDistinctIdentifier() { |
| return distinctIdentifier; |
| } |
| |
| /** |
| * Returns the actual <b>SELECT</b> identifier found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <b>SELECT</b> identifier that was actually parsed |
| */ |
| public final String getActualIdentifier() { |
| return identifier; |
| } |
| |
| /** |
| * Returns the {@link Expression} representing the select items. |
| * |
| * @return The expression representing the select items |
| */ |
| public final Expression getSelectExpression() { |
| if (selectExpression == null) { |
| selectExpression = buildNullExpression(); |
| } |
| return selectExpression; |
| } |
| |
| /** |
| * Returns the unique identifier of the {@link JPQLQueryBNF} for the list of select items to parse. |
| * |
| * @return The ID of the query BNF for the list of select items to parse |
| */ |
| public abstract String getSelectItemQueryBNFId(); |
| |
| /** |
| * Determines whether the identifier <b>DISTINCT</b> was parsed or not. |
| * |
| * @return <code>true</code> if the identifier <b>DISTINCT</b> was parsed; |
| * <code>false</code> otherwise |
| */ |
| public final boolean hasDistinct() { |
| return distinctIdentifier != null; |
| } |
| |
| /** |
| * Determines whether the list of select items was parsed. |
| * |
| * @return <code>true</code> the list of select items was parsed; |
| * <code>false</code> otherwise |
| */ |
| public final boolean hasSelectExpression() { |
| return selectExpression != null && |
| !selectExpression.isNull(); |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>DISTINCT</b>. |
| * |
| * @return <code>true</code> if there was a whitespace after <b>DISTINCT</b>; |
| * <code>false</code> otherwise |
| */ |
| public final boolean hasSpaceAfterDistinct() { |
| return hasSpaceAfterDistinct; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>SELECT</b>. |
| * |
| * @return <code>true</code> if there was a whitespace after <b>SELECT</b>; |
| * <code>false</code> otherwise |
| */ |
| public final boolean hasSpaceAfterSelect() { |
| return hasSpaceAfterSelect; |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse 'SELECT' |
| identifier = wordParser.moveForward(SELECT); |
| |
| hasSpaceAfterSelect = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse 'DISTINCT' |
| if (wordParser.startsWithIdentifier(DISTINCT)) { |
| distinctIdentifier = wordParser.moveForward(DISTINCT); |
| hasSpaceAfterDistinct = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Parse the select expression |
| selectExpression = parse(wordParser, getSelectItemQueryBNFId(), tolerant); |
| } |
| |
| @Override |
| protected boolean shouldSkipLiteral(AbstractExpression expression) { |
| return false; |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // 'SELECT' |
| writer.append(actual ? identifier : SELECT); |
| |
| if (hasSpaceAfterSelect) { |
| writer.append(SPACE); |
| } |
| |
| // 'DISTINCT' |
| if (distinctIdentifier != null) { |
| writer.append(actual ? distinctIdentifier : DISTINCT); |
| } |
| |
| if (hasSpaceAfterDistinct) { |
| writer.append(SPACE); |
| } |
| |
| // Select expression |
| if (selectExpression != null) { |
| selectExpression.toParsedText(writer, actual); |
| } |
| } |
| } |