| /* |
| * Copyright (c) 2012, 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.Collection; |
| import java.util.List; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * The <b>UNION</b> clause allows the results of two queries to be combined. |
| * |
| * <div><b>BNF:</b> <code>union_clause ::= <b>{ UNION | INTERSECT | EXCEPT }</b> [ALL] subquery</code></div> |
| * |
| * @version 2.5 |
| * @since 2.4 |
| * @author James Sutherland |
| */ |
| public final class UnionClause extends AbstractExpression { |
| |
| /** |
| * The actual identifier found in the string representation of the JPQL query. |
| */ |
| private String actualIdentifier; |
| |
| /** |
| * The actual <b>All</b> identifier found in the string representation of the JPQL query. |
| */ |
| private String allIdentifier; |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>ALL</b>. |
| */ |
| private boolean hasSpaceAfterAll; |
| |
| /** |
| * Determines whether a whitespace was parsed after <b>UNION</b>. |
| */ |
| private boolean hasSpaceAfterIdentifier; |
| |
| /** |
| * The {@link Expression} representing the unioned query. |
| */ |
| private AbstractExpression query; |
| |
| /** |
| * Creates a new <code>UnionClause</code>. |
| * |
| * @param parent The parent of this expression |
| * @param identifier Either <code><b>UNION</b></code>, <code><b>INTERSECT</b></code> or |
| * <code><b>EXCEPT</b></code> |
| */ |
| public UnionClause(AbstractExpression parent, String identifier) { |
| super(parent, identifier); |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| acceptUnknownVisitor(visitor); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getQuery().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getQuery()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // 'UNION' or 'INTERSECT' or 'EXCEPT' |
| children.add(buildStringExpression(getText())); |
| |
| if (hasSpaceAfterIdentifier) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'ALL' |
| if (allIdentifier != null) { |
| children.add(buildStringExpression(ALL)); |
| |
| if (hasSpaceAfterAll) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| } |
| |
| // Subquery |
| if (query != null) { |
| children.add(query); |
| } |
| } |
| |
| @Override |
| public JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((query != null) && query.isAncestor(expression)) { |
| return getQueryBNF(SubqueryBNF.ID); |
| } |
| |
| return super.findQueryBNF(expression); |
| } |
| |
| /** |
| * Returns the actual <code><b>ALL</b></code> found in the string representation of the JPQL |
| * query, which has the actual case that was used. |
| * |
| * @return The <code><b>ALL</b></code> identifier that was actually parsed |
| */ |
| public String getActualAll() { |
| return allIdentifier; |
| } |
| |
| /** |
| * Returns the actual identifier found in the string representation of the JPQL query, which |
| * has the actual case that was used. |
| * |
| * @return The identifier that was actually parsed |
| */ |
| public String getActualIdentifier() { |
| return actualIdentifier; |
| } |
| |
| /** |
| * Returns the union identifier. |
| * |
| * @return Either "UNION", "INTERSECT", "EXCEPT" |
| */ |
| public String getIdentifier() { |
| return getText(); |
| } |
| |
| /** |
| * Returns the {@link Expression} representing the unioned query. |
| * |
| * @return The {@link Expression} representing the subquery |
| */ |
| public Expression getQuery() { |
| if (query == null) { |
| query = buildNullExpression(); |
| } |
| return query; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(UnionClauseBNF.ID); |
| } |
| |
| /** |
| * Determines whether <code><b>ALL</b></code> was parsed. |
| * |
| * @return <code>true</code> if <code><b>ALL</b></code> was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasAll() { |
| return allIdentifier != null; |
| } |
| |
| /** |
| * Determines whether the query was parsed. |
| * |
| * @return <code>true</code> the query was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasQuery() { |
| return query != null && |
| !query.isNull(); |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after <code><b>ALL</b></code>. |
| * |
| * @return <code>true</code> if a whitespace was parsed after <code><b>ALL</b></code>; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterAll() { |
| return hasSpaceAfterAll; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the identifier. |
| * |
| * @return <code>true</code> if a whitespace was parsed after the identifier; <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterIdentifier() { |
| return hasSpaceAfterIdentifier; |
| } |
| |
| /** |
| * Determines whether this {@link UnionClause} uses the <code><b>EXCEPT</b></code> identifier. |
| * |
| * @return <code>true</code> if the identifier is <code><b>EXCEPT</b></code>; <code>false</code> otherwise |
| */ |
| public boolean isExcept() { |
| return getText() == EXCEPT; |
| } |
| |
| /** |
| * Determines whether this {@link UnionClause} uses the <code><b>INTERSECT</b></code> identifier. |
| * |
| * @return <code>true</code> if the identifier is <code><b>INTERSECT</b></code>; <code>false</code> otherwise |
| */ |
| public boolean isIntersect() { |
| return getText() == INTERSECT; |
| } |
| |
| @Override |
| protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) { |
| return word.equalsIgnoreCase(UNION) || |
| word.equalsIgnoreCase(INTERSECT) || |
| word.equalsIgnoreCase(EXCEPT) || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| /** |
| * Determines whether this {@link UnionClause} uses the <code><b>UNION</b></code> identifier. |
| * |
| * @return <code>true</code> if the identifier is <code><b>UNION</b></code>; <code>false</code> otherwise |
| */ |
| public boolean isUnion() { |
| return getText() == UNION; |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse the identifier |
| String identifier = parseIdentifier(); |
| actualIdentifier = wordParser.moveForward(identifier); |
| setText(identifier); |
| |
| hasSpaceAfterIdentifier = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse 'ALL' |
| if (wordParser.startsWithIdentifier(ALL)) { |
| allIdentifier = wordParser.moveForward(ALL); |
| hasSpaceAfterAll = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Query |
| if (tolerant) { |
| query = parse(wordParser, SubqueryBNF.ID, tolerant); |
| } |
| else { |
| query = new SimpleSelectStatement(this); |
| query.parse(wordParser, tolerant); |
| } |
| } |
| |
| /** |
| * Parses the JPQL identifier identifier the type of union. |
| * |
| * @return Either {@link Expression#UNION UNION}, {@link Expression#INTERSECT INTERSECT} or |
| * {@link Expression#EXCEPT EXCEPT} |
| */ |
| protected String parseIdentifier() { |
| switch (getText().charAt(0)) { |
| case 'U': case 'u': return UNION; |
| case 'I': case 'i': return INTERSECT; |
| case 'E': case 'e': return EXCEPT; |
| default: return null; // Never happens |
| } |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // 'UNION', 'INTERSECT' or 'EXCEPT' |
| writer.append(actual ? actualIdentifier : getText()); |
| |
| if (hasSpaceAfterIdentifier) { |
| writer.append(SPACE); |
| } |
| |
| // 'ALL' |
| if (allIdentifier != null) { |
| writer.append(actual ? allIdentifier : ALL); |
| |
| if (hasSpaceAfterAll) { |
| writer.append(SPACE); |
| } |
| } |
| |
| // Query |
| if (query != null) { |
| query.toParsedText(writer, actual); |
| } |
| } |
| } |