| /* |
| * 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.Collection; |
| import java.util.List; |
| import org.eclipse.persistence.jpa.jpql.ExpressionTools; |
| import org.eclipse.persistence.jpa.jpql.WordParser; |
| |
| /** |
| * An orderby_item must be one of the following: |
| * <ol> |
| * <li> A {@link StateFieldPathExpression state_field_path_expression} that evaluates to an orderable |
| * state field of an entity or embeddable class abstract schema type designated in the SELECT clause |
| * by one of the following: |
| * <ul> |
| * <li>A general_identification_variable |
| * <li>A single_valued_object_path_expression |
| * </ul> |
| * <li>A {@link StateFieldPathExpression state_field_path_expression} that evaluates to the same |
| * state field of the same entity or embeddable abstract schema type as a {@link StateFieldPathExpression |
| * state_field_path_expression} in the <b>SELECT</b> clause |
| * <li>A {@link ResultVariable result_variable} that refers to an orderable item in the <b>SELECT</b> |
| * clause for which the same {@link ResultVariable result_variable} has been specified. This may be |
| * the result of an aggregate_expression, a <code>scalar_expression</code>, or a {@link |
| * StateFieldPathExpression state_field_path_expression} in the <b>SELECT</b> clause. |
| * </ol> |
| * <br> |
| * The keyword <b>ASC</b> specifies that ascending ordering be used for the associated orderby_item; |
| * the keyword <b>DESC</b> specifies that descending ordering be used. Ascending ordering is the |
| * default. |
| * <br> |
| * The keyword <b>NULLS FIRST</b> specifies that nulls first ordering be used for the associated orderby_item; |
| * the keyword <b>NULLS LAST</b> specifies that nulls last ordering be used. Ascending ordering is the |
| * default. |
| * <br> |
| * JPA 1.0: |
| * <div><b>BNF:</b> <code>orderby_item ::= state_field_path_expression [ ASC | DESC ]</code></div> |
| * <br> |
| * JPA 2.0 |
| * <div><b>BNF:</b> <code>orderby_item ::= state_field_path_expression | result_variable [ ASC | DESC ]</code></div> |
| * <br> |
| * EclipseLink 2.4: |
| * <div><b>BNF:</b> <code>orderby_item ::= state_field_path_expression | result_variable [ ASC | DESC ] [ NULLS FIRST | NULLS LAST ]</code></div> |
| * |
| * @version 2.5 |
| * @since 2.3 |
| * @author Pascal Filion |
| */ |
| @SuppressWarnings("nls") |
| public final class OrderByItem extends AbstractExpression { |
| |
| /** |
| * The {@link Expression} representing the order by expression. |
| */ |
| private AbstractExpression expression; |
| |
| /** |
| * The actual 'FIRST' identifier found in the string representation of the JPQL query. |
| */ |
| private String firstIdentifier; |
| |
| /** |
| * Determines whether a whitespace was parsed after the order by expression. |
| */ |
| private boolean hasSpaceAfterExpression; |
| |
| /** |
| * Determines whether a whitespace was parsed after <code><b>NULLS</b></code>. |
| */ |
| private boolean hasSpaceAfterNulls; |
| |
| /** |
| * Determines whether a whitespace was parsed after the ordering. |
| */ |
| private boolean hasSpaceAfterOrdering; |
| |
| /** |
| * The actual 'LAST' identifier found in the string representation of the JPQL query. |
| */ |
| private String lastIdentifier; |
| |
| /** |
| * The keyword <b>NULLS FIRST</b> specifies ordering null first; the keyword <b>NULLS LAST</b> |
| * specifies ordering nulls last. |
| */ |
| private NullOrdering nullOrdering; |
| |
| /** |
| * The actual 'NULLS' identifier found in the string representation of the JPQL query. |
| */ |
| private String nullsIdentifier; |
| |
| /** |
| * The keyword <b>ASC</b> specifies that ascending ordering be used; the keyword <b>DESC</b> |
| * specifies that descending ordering be used. Ascending ordering is the default. |
| */ |
| private Ordering ordering; |
| |
| /** |
| * The actual ordering identifier found in the string representation of the JPQL query. |
| */ |
| private String orderingIdentifier; |
| |
| /** |
| * Creates a new <code>OrderByItem</code>. |
| * |
| * @param parent The parent of this expression |
| */ |
| public OrderByItem(AbstractExpression parent) { |
| super(parent); |
| } |
| |
| @Override |
| public void accept(ExpressionVisitor visitor) { |
| visitor.visit(this); |
| } |
| |
| @Override |
| public void acceptChildren(ExpressionVisitor visitor) { |
| getExpression().accept(visitor); |
| } |
| |
| @Override |
| protected void addChildrenTo(Collection<Expression> children) { |
| children.add(getExpression()); |
| } |
| |
| @Override |
| protected void addOrderedChildrenTo(List<Expression> children) { |
| |
| // Order By expression |
| if (expression != null) { |
| children.add(expression); |
| } |
| |
| if (hasSpaceAfterExpression) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // Ordering type |
| if (ordering != Ordering.DEFAULT) { |
| children.add(buildStringExpression(ordering.toString())); |
| } |
| |
| if (hasSpaceAfterOrdering) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'NULLS' |
| if (nullsIdentifier != null) { |
| children.add(buildStringExpression(NULLS)); |
| } |
| |
| if (hasSpaceAfterNulls) { |
| children.add(buildStringExpression(SPACE)); |
| } |
| |
| // 'FIRST' |
| if (firstIdentifier != null) { |
| children.add(buildStringExpression(FIRST)); |
| } |
| // 'LAST' |
| else if (lastIdentifier != null) { |
| children.add(buildStringExpression(LAST)); |
| } |
| } |
| |
| @Override |
| public JPQLQueryBNF findQueryBNF(Expression expression) { |
| |
| if ((this.expression != null) && this.expression.isAncestor(expression)) { |
| return getQueryBNF(InternalOrderByItemBNF.ID); |
| } |
| |
| return super.findQueryBNF(expression); |
| } |
| |
| /** |
| * Returns the actual <code>null</code> ordering identifier found in the string representation of |
| * the JPQL query, which has the actual case that was used. |
| * |
| * @return The <code>null</code> ordering identifier that was actually parsed, if one was present, |
| * otherwise an empty string is returned |
| */ |
| public String getActualNullOrdering() { |
| |
| // NULLS FIRST |
| if ((nullsIdentifier != null) && (firstIdentifier != null)) { |
| return nullsIdentifier + SPACE + firstIdentifier; |
| } |
| |
| // NULLS LAST |
| if ((nullsIdentifier != null) && (lastIdentifier != null)) { |
| return nullsIdentifier + SPACE + lastIdentifier; |
| } |
| |
| if (nullsIdentifier != null) { |
| return nullsIdentifier; |
| } |
| |
| if (firstIdentifier != null) { |
| return firstIdentifier; |
| } |
| else if (lastIdentifier != null) { |
| return lastIdentifier; |
| } |
| |
| return ExpressionTools.EMPTY_STRING; |
| } |
| |
| /** |
| * Returns the actual ordering identifier found in the string representation of the JPQL query, |
| * which has the actual case that was used. |
| * |
| * @return The ordering identifier that was actually parsed, if one was present, otherwise an |
| * empty string is returned |
| */ |
| public String getActualOrdering() { |
| return (orderingIdentifier != null) ? orderingIdentifier : ExpressionTools.EMPTY_STRING; |
| } |
| |
| /** |
| * Returns the {@link Expression} that represents the order by expression. |
| * |
| * @return The expression that was parsed representing the order by expression |
| */ |
| public Expression getExpression() { |
| if (expression == null) { |
| expression = buildNullExpression(); |
| } |
| return expression; |
| } |
| |
| /** |
| * Returns the enum constant representing the null ordering type. |
| * |
| * @return The constant representing the null ordering, in the case the ordering was not parsed, |
| * then {@link NullOrdering#DEFAULT} is returned |
| */ |
| public NullOrdering getNullOrdering() { |
| return nullOrdering; |
| } |
| |
| /** |
| * Returns the enum constant representing the ordering type. |
| * |
| * @return The constant representing the ordering, in the case the ordering was not parsed, then |
| * {@link Ordering#DEFAULT} is returned |
| */ |
| public Ordering getOrdering() { |
| return ordering; |
| } |
| |
| @Override |
| public JPQLQueryBNF getQueryBNF() { |
| return getQueryBNF(OrderByItemBNF.ID); |
| } |
| |
| /** |
| * Determines whether the order by expression was parsed. |
| * |
| * @return <code>true</code> if the order by expression was parsed; <code>false</code> otherwise |
| */ |
| public boolean hasExpression() { |
| return expression != null && |
| !expression.isNull(); |
| } |
| |
| /** |
| * Determines whether the <code><b>NULLS</b></code> identifier was parsed. |
| * |
| * @return <code>true</code> if the <code><b>NULLS</b></code> identifier was parsed; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasNulls() { |
| return nullsIdentifier != null; |
| } |
| |
| /** |
| * Determines whether <code><b>ASC</b></code> or <code><b>DESC</b></code> was parsed. |
| * |
| * @return <code>true</code> if the ordering status was parsed; <code>false</code> otherwise |
| * @since 2.5 |
| */ |
| public boolean hasOrdering() { |
| return ordering != Ordering.DEFAULT; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the order by expression. |
| * |
| * @return <code>true</code> if there was a whitespace after the order by expression; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterExpression() { |
| return hasSpaceAfterExpression; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the <code>NULLS</code> identifier. If the |
| * composite identifier was fully parsed - <code>NULLS FIRST</code> or <code>NULLS LAST</code> - |
| * then this is always <code>true</code>, but if only <code>NULLS</code> was parsed, then this |
| * can be useful to determine if there was a space after. |
| * |
| * @return <code>true</code> if there was a whitespace after the <code>NULLS</code> identifier; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterNulls() { |
| return hasSpaceAfterNulls; |
| } |
| |
| /** |
| * Determines whether a whitespace was parsed after the ordering. |
| * |
| * @return <code>true</code> if there was a whitespace after the ordering; |
| * <code>false</code> otherwise |
| */ |
| public boolean hasSpaceAfterOrdering() { |
| return hasSpaceAfterOrdering; |
| } |
| |
| /** |
| * Determines whether the ordering was specified as being ascendant. |
| * |
| * @return <code>true</code> if <b>ASC</b> was parsed; <code>false</code> otherwise |
| */ |
| public boolean isAscending() { |
| return ordering == Ordering.ASC; |
| } |
| |
| /** |
| * Determines whether the ordering was not specified. |
| * |
| * @return <code>true</code> if no ordering was parsed; <code>false</code> otherwise |
| */ |
| public boolean isDefault() { |
| return ordering == Ordering.DEFAULT; |
| } |
| |
| /** |
| * Determines whether the ordering was specified as being descendant. |
| * |
| * @return <code>true</code> if <b>DESC</b> was parsed; <code>false</code> otherwise |
| */ |
| public boolean isDescending() { |
| return ordering == Ordering.DESC; |
| } |
| |
| /** |
| * Determines whether the ordering was specified as being nulls first. |
| * |
| * @return <code>true</code> if <b>NULLS FIRST</b> was parsed; <code>false</code> otherwise |
| */ |
| public boolean isNullsFirst() { |
| return nullOrdering == NullOrdering.NULLS_FIRST; |
| } |
| |
| /** |
| * Determines whether the ordering was specified as being nulls first. |
| * |
| * @return <code>true</code> if <b>NULLS LAST</b> was parsed; <code>false</code> otherwise |
| */ |
| public boolean isNullsLast() { |
| return nullOrdering == NullOrdering.NULLS_LAST; |
| } |
| |
| @Override |
| protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) { |
| return word.equalsIgnoreCase(ASC) || |
| word.equalsIgnoreCase(DESC) || |
| word.equalsIgnoreCase("NULLS") || |
| super.isParsingComplete(wordParser, word, expression); |
| } |
| |
| @Override |
| protected void parse(WordParser wordParser, boolean tolerant) { |
| |
| // Parse the state field path expression |
| expression = parse(wordParser, InternalOrderByItemBNF.ID, tolerant); |
| |
| hasSpaceAfterExpression = wordParser.skipLeadingWhitespace() > 0; |
| |
| // Parse ASC/DESC |
| if (!wordParser.isTail()) { |
| String word = wordParser.word(); |
| |
| // Parse 'ASC' |
| if (word.equalsIgnoreCase(ASC)) { |
| ordering = Ordering.ASC; |
| orderingIdentifier = wordParser.moveForward(ASC.length()); |
| } |
| // Parse 'DESC' |
| else if (word.equalsIgnoreCase(DESC)) { |
| ordering = Ordering.DESC; |
| orderingIdentifier = wordParser.moveForward(DESC.length()); |
| } |
| else { |
| ordering = Ordering.DEFAULT; |
| } |
| } |
| else { |
| ordering = Ordering.DEFAULT; |
| } |
| |
| // Parse NULLS FIRST/NULLS LAST |
| if (!wordParser.isTail()) { |
| int count = wordParser.skipLeadingWhitespace(); |
| hasSpaceAfterOrdering = (count > 0); |
| |
| // Parse 'NULLS' |
| if (wordParser.startsWithIdentifier(NULLS)) { |
| nullsIdentifier = wordParser.moveForward(NULLS); |
| hasSpaceAfterNulls = wordParser.skipLeadingWhitespace() > 0; |
| } |
| |
| // Parse 'FIRT' |
| if (wordParser.startsWithIdentifier(FIRST)) { |
| firstIdentifier = wordParser.moveForward(FIRST); |
| } |
| // Parse 'LAST' |
| else if (wordParser.startsWithIdentifier(LAST)) { |
| lastIdentifier = wordParser.moveForward(LAST); |
| } |
| |
| if ((nullsIdentifier != null) && (firstIdentifier != null)) { |
| nullOrdering = NullOrdering.NULLS_FIRST; |
| } |
| else if ((nullsIdentifier != null) && (lastIdentifier != null)) { |
| nullOrdering = NullOrdering.NULLS_LAST; |
| } |
| else { |
| nullOrdering = NullOrdering.DEFAULT; |
| } |
| } |
| else { |
| nullOrdering = NullOrdering.DEFAULT; |
| } |
| } |
| |
| @Override |
| protected void toParsedText(StringBuilder writer, boolean actual) { |
| |
| // Order By expression |
| if (expression != null) { |
| expression.toParsedText(writer, actual); |
| } |
| |
| if (hasSpaceAfterExpression) { |
| writer.append(SPACE); |
| } |
| |
| // Ordering type |
| if (ordering != Ordering.DEFAULT) { |
| writer.append(actual ? orderingIdentifier : ordering.name()); |
| } |
| |
| if (hasSpaceAfterOrdering) { |
| writer.append(SPACE); |
| } |
| |
| // 'NULLS' |
| if (nullsIdentifier != null) { |
| writer.append(actual? nullsIdentifier : NULLS); |
| } |
| |
| if (hasSpaceAfterNulls) { |
| writer.append(SPACE); |
| } |
| |
| // 'FIRST' |
| if (firstIdentifier != null) { |
| writer.append(actual? firstIdentifier : FIRST); |
| } |
| // 'LAST' |
| else if (lastIdentifier != null) { |
| writer.append(actual? lastIdentifier : LAST); |
| } |
| } |
| |
| /** |
| * This enumeration lists all the possible choices for ordering nulls in an item. |
| */ |
| public enum NullOrdering { |
| |
| /** |
| * The constant used when the ordering is not specify. |
| */ |
| DEFAULT(ExpressionTools.EMPTY_STRING), |
| |
| /** |
| * The constant for 'NULLS FIRST', which tells to order nulls first. |
| */ |
| NULLS_FIRST(Expression.NULLS_FIRST), |
| |
| /** |
| * The constant for 'NULLS LAST', which tells to order nulls last. |
| */ |
| NULLS_LAST(Expression.NULLS_LAST); |
| |
| /** |
| * The actual composite identifier. |
| */ |
| private String identifier; |
| |
| /** |
| * Creates a new <code>NullOrdering</code>. |
| * |
| * @param identifier The actual composite identifier |
| */ |
| private NullOrdering(String identifier) { |
| this.identifier = identifier; |
| } |
| |
| /** |
| * Returns the actual JPQL composite identifiers identified by this enum constant. |
| * |
| * @return The composite identifiers |
| */ |
| public String getIdentifier() { |
| return identifier; |
| } |
| |
| @Override |
| public String toString() { |
| return identifier; |
| } |
| } |
| |
| /** |
| * This enumeration lists all the possible choices for ordering an item. |
| */ |
| public enum Ordering { |
| |
| /** |
| * The constant for 'ASC', which tells to order the items in ascending ordering. |
| */ |
| ASC, |
| |
| /** |
| * The constant used when the ordering is not specify, the default is ascending ordering. |
| */ |
| DEFAULT, |
| |
| /** |
| * The constant for 'DESC', which tells to order the items in descending ordering. |
| */ |
| DESC |
| } |
| } |