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/*
* Copyright (c) 2006, 2020 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;
/**
* A CollectionExpression wraps many expression which they are separated by spaces
* and/or commas.
*
* BNF: expression ::= child_item {, child_item }*
*
* or
*
* BNF: expression ::= child_item { child_item }*
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
@SuppressWarnings("nls")
public final class CollectionExpression extends AbstractExpression {
/**
* The {@link Expression Expressions} that forms a collection within another expression.
*/
private List children;
/**
* The list of flags used to determine where to separate two child {@link Expression Expressions}
* with a comma or with a space only.
*/
private List commas;
/**
* Flag used to determine when a space is required after a comma.
*/
private List spaces;
/**
* Creates a new CollectionExpression.
*
* @param parent The parent of this expression
* @param children The list of children that are regrouped together
* @param spaces The list of flags used to determine when to add a space after an {@link Expression}
* @param commas The list of flags used to determine when to add a comma after an {@link Expression}
*/
public CollectionExpression(AbstractExpression parent,
List children,
List commas,
List spaces) {
this(parent, children, commas, spaces, false);
}
/**
* Creates a new CollectionExpression.
*
* @param parent The parent of this expression
* @param children The list of children that are regrouped together
* @param commas The list of flags used to determine when to add a comma after an {@link Expression}
* @param spaces The list of flags used to determine when to add a space after an {@link Expression}
* @param temporary Flag used to determine if this expression is temporarily used, which means
* the children will not be parented to this object
*/
public CollectionExpression(AbstractExpression parent,
List children,
List commas,
List spaces,
boolean temporary) {
super(parent);
this.children = children;
this.commas = commas;
this.spaces = spaces;
if (!temporary) {
updateBackpointers();
}
}
@Override
public void accept(ExpressionVisitor visitor) {
visitor.visit(this);
}
/**
* Visits the child {@link Expression} at the given position by the given {@link ExpressionVisitor
* visitor}.
*
* @param index The index of the child to visit
* @param visitor The {@link ExpressionVisitor} to visit a specific child
* @since 2.4
*/
public void accept(int index, ExpressionVisitor visitor) {
getChild(index).accept(visitor);
}
@Override
public void acceptChildren(ExpressionVisitor visitor) {
for (Expression child : children()) {
child.accept(visitor);
}
}
@Override
protected void addChildrenTo(Collection children) {
// Make sure all children are non null
for (int index = 0, childCount = this.children.size(); index < childCount; index++) {
getChildInternal(index);
}
children.addAll(this.children);
}
@Override
protected void addOrderedChildrenTo(List children) {
children();
for (int index = 0, count = this.children.size(); index < count; index++) {
Expression expression = getChild(index);
children.add(expression);
// Write ','
if (hasComma(index)) {
children.add(buildStringExpression(COMMA));
}
// Write whitespace
if (hasSpace(index)) {
children.add(buildStringExpression(SPACE));
}
}
}
/**
* Returns the count of child {@link Expression expressions}.
*
* @return The total count of {@link Expression expressions} aggregated with spaces and/or commas
*/
public int childrenSize() {
children();
return children.size();
}
/**
* Determines whether this {@link CollectionExpression} ends with a comma, which means the last
* {@link Expression} is a "null" expression.
*
* @return true if the string representation of this {@link CollectionExpression}
* ends with a comma (the ending space is not checked)
*/
public boolean endsWithComma() {
children();
if (children.get(children.size() - 1).isNull()) {
return commas.get(commas.size() - 2);
}
return false;
}
/**
* Determines whether this {@link CollectionExpression} ends with a space, which means the last
* {@link Expression} is a "null" expression.
*
* @return true if the string representation of this {@link CollectionExpression}
* ends with a space (the ending comma is not checked)
*/
public boolean endsWithSpace() {
children();
if (children.get(children.size() - 1).isNull()) {
return spaces.get(spaces.size() - 2);
}
return false;
}
@Override
public JPQLQueryBNF findQueryBNF(Expression expression) {
return getParent().findQueryBNF(expression);
}
/**
* Retrieves the child {@link Expression} at the given position.
*
* @param index The position of the child {@link Expression} to retrieve
* @return The child {@link Expression} at the given position
*/
public Expression getChild(int index) {
return getChildInternal(index);
}
private AbstractExpression getChildInternal(int index) {
AbstractExpression child = children.get(index);
if (child == null) {
child = buildNullExpression();
children.set(index, child);
}
return child;
}
@Override
public JPQLQueryBNF getQueryBNF() {
return getParent().getQueryBNF();
}
/**
* Determines whether a comma was parsed at the given position. The index is the position of the
* comma that is following the child at the same position.
*
* @param index The index of the child {@link Expression} to verify if there is a comma following it
* @return true if a comma is following the child {@link Expression} at the given
* index; false otherwise
*/
public boolean hasComma(int index) {
children();
return (index < commas.size()) && commas.get(index);
}
/**
* Determines whether a space was parsed at the given position. The index is the position of the
* space that is following the child at the same position, which is after a comma, if one was
* also parsed at that location.
*
* @param index The index of the child {@link Expression} to verify if there is a space following
* it, which could be after a comma, if one was parsed
* @return true if a space is following the child {@link Expression} at the given
* index; false otherwise
*/
public boolean hasSpace(int index) {
children();
return (index < spaces.size()) && (spaces.get(index) || hasComma(index) && (index + 1 < children.size() ? !getChildInternal(index + 1).isNull() : false));
}
/**
* Retrieves the index of the given Expression.
*
* @param expression The Expression that might be a child of this expression
* @return The index in the collection of the given Expression or -1 if it is not a child
*/
public int indexOf(Expression expression) {
children();
return children.indexOf(expression);
}
@Override
protected void parse(WordParser wordParser, boolean tolerant) {
throw new IllegalAccessError("This method shouln't be invoked, text=" + wordParser);
}
/**
* Returns a string representation of this {@link Expression} and its children. The expression
* should contain whitespace even if the beautified version would not have any. For instance,
* "SELECT e " should be returned where {@link Expression#toParsedText()} would return "SELECT e".
*
* @param endIndex The index used to determine when to create the string representation, which
* is exclusive
* @return The string representation of this {@link Expression}
*/
public String toActualText(int endIndex) {
StringBuilder writer = new StringBuilder();
toParsedText(writer, endIndex, true);
return writer.toString();
}
/**
* Generates a string representation of this {@link CollectionExpression}.
*
* @param endIndex The index used to determine when to create the string representation, which
* is exclusive
* @return The string representation of this {@link Expression}
*/
public String toParsedText(int endIndex) {
StringBuilder writer = new StringBuilder();
toParsedText(writer, endIndex, false);
return writer.toString();
}
@Override
protected void toParsedText(StringBuilder writer, boolean actual) {
toParsedText(writer, childrenSize(), actual);
}
private void toParsedText(StringBuilder writer, int endIndex, boolean actual) {
for (int index = 0, count = children.size(); index < endIndex; index++) {
AbstractExpression expression = children.get(index);
// Write the child expression
if (expression != null) {
expression.toParsedText(writer, actual);
}
// Write ','
if (commas.get(index)) {
writer.append(COMMA);
// If there is a space, then add it
if (spaces.get(index)) {
writer.append(SPACE);
}
// Otherwise check if the next expression is not null, if it's null,
// then a space will not be added
else if (index + 1 < count) {
AbstractExpression nextExpression = children.get(index + 1);
if ((nextExpression != null) && !nextExpression.isNull()) {
writer.append(SPACE);
}
}
}
// Write ' '
else if (spaces.get(index)) {
writer.append(SPACE);
}
}
}
private void updateBackpointers() {
for (AbstractExpression child : children) {
if (child != null) {
child.setParent(this);
}
}
}
}