/*******************************************************************************
* Copyright (c) 2006, 2015 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 v1.0 and Eclipse Distribution License v. 1.0
* which accompanies this distribution.
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* 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;
/**
* The <b>LIKE</b> condition is used to specify a search for a pattern.
* <p>
* The <code>string_expression</code> must have a string value. The <code>pattern_value</code> is a
* string literal or a string-valued input parameter in which an underscore (_) stands for any
* single character, a percent (%) character stands for any sequence of characters (including the
* empty sequence), and all other characters stand for themselves. The optional <code>escape_character</code>
* is a single-character string literal or a character-valued input parameter (i.e., char or
* Character) and is used to escape the special meaning of the underscore and percent characters in
* <code>pattern_value</code>.
*
* <div><b>BNF:</b> <code>like_expression ::= string_expression [NOT] LIKE pattern_value [ESCAPE escape_character]</code><p></div>
*
* @version 2.5
* @since 2.3
* @author Pascal Filion
*/
public final class LikeExpression extends AbstractExpression {
/**
* The {@link Expression} representing the escape character, which is either a single character
* or an input parameter.
*/
private AbstractExpression escapeCharacter;
/**
* The actual <b>escape</b> identifier found in the string representation of the JPQL query.
*/
private String escapeIdentifier;
/**
* Determines whether a whitespace was parsed after <b>ESCAPE</b>.
*/
private boolean hasSpaceAfterEscape;
/**
* Determines whether a whitespace was parsed after <b>LIKE</b>.
*/
private boolean hasSpaceAfterLike;
/**
* Determines whether a whitespace was parsed after the pattern value.
*/
private boolean hasSpaceAfterPatternValue;
/**
* The actual <b>LIKE</b> identifier found in the string representation of the JPQL query.
*/
private String likeIdentifier;
/**
* The actual <b>NOT</b> identifier found in the string representation of the JPQL query.
*/
private String notIdentifier;
/**
* The {@link Expression} representing the pattern value.
*/
private AbstractExpression patternValue;
/**
* The {@link Expression} representing the string expression.
*/
private AbstractExpression stringExpression;
/**
* Creates a new <code>LikeExpression</code>.
*
* @param parent The parent of this expression
* @param stringExpression The first part of this expression, which is the string expression
*/
public LikeExpression(AbstractExpression parent, AbstractExpression stringExpression) {
super(parent, LIKE);
if (stringExpression != null) {
this.stringExpression = stringExpression;
this.stringExpression.setParent(this);
}
}
/**
* {@inheritDoc}
*/
public void accept(ExpressionVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
public void acceptChildren(ExpressionVisitor visitor) {
getStringExpression().accept(visitor);
getPatternValue().accept(visitor);
getEscapeCharacter().accept(visitor);
}
/**
* {@inheritDoc}
*/
@Override
protected void addChildrenTo(Collection<Expression> children) {
children.add(getStringExpression());
children.add(getPatternValue());
children.add(getEscapeCharacter());
}
/**
* {@inheritDoc}
*/
@Override
protected void addOrderedChildrenTo(List<Expression> children) {
// String expression
if (stringExpression != null) {
children.add(stringExpression);
}
// 'NOT'
if (notIdentifier != null) {
children.add(buildStringExpression(SPACE));
children.add(buildStringExpression(NOT));
}
children.add(buildStringExpression(SPACE));
// 'LIKE'
children.add(buildStringExpression(LIKE));
if (hasSpaceAfterLike) {
children.add(buildStringExpression(SPACE));
}
// Pattern value
if (patternValue != null) {
children.add(patternValue);
}
if (hasSpaceAfterPatternValue) {
children.add(buildStringExpression(SPACE));
}
// 'ESCAPE'
if (escapeIdentifier != null) {
children.add(buildStringExpression(ESCAPE));
}
if (hasSpaceAfterEscape) {
children.add(buildStringExpression(SPACE));
}
// Escape character
if (escapeCharacter != null) {
children.add(escapeCharacter);
}
}
/**
* {@inheritDoc}
*/
@Override
public JPQLQueryBNF findQueryBNF(Expression expression) {
if ((patternValue != null) && patternValue.isAncestor(expression)) {
return getQueryBNF(PatternValueBNF.ID);
}
if ((escapeCharacter != null) && escapeCharacter.isAncestor(expression)) {
return getQueryBNF(LikeExpressionEscapeCharacterBNF.ID);
}
return super.findQueryBNF(expression);
}
/**
* Returns the actual <b>ESCAPE</b> found in the string representation of the JPQL query, which
* has the actual case that was used.
*
* @return The <b>ESCAPE</b> identifier that was actually parsed, or an empty string if it was
* not parsed
*/
public String getActualEscapeIdentifier() {
return (escapeIdentifier != null) ? escapeIdentifier : ExpressionTools.EMPTY_STRING;
}
/**
* Returns the actual <b>LIKE</b> found in the string representation of the JPQL query, which
* has the actual case that was used.
*
* @return The <b>LIKE</b> identifier that was actually parsed
*/
public String getActualLikeIdentifier() {
return likeIdentifier;
}
/**
* Returns the actual <b>NOT</b> found in the string representation of the JPQL query, which has
* the actual case that was used.
*
* @return The <b>NOT</b> identifier that was actually parsed, or an empty string if it was not
* parsed
*/
public String getActualNotIdentifier() {
return (notIdentifier != null) ? notIdentifier : ExpressionTools.EMPTY_STRING;
}
/**
* Returns the {@link Expression} that represents the escape character, which is either a single
* character or an input parameter.
*
* @return The expression that was parsed representing the escape character
*/
public Expression getEscapeCharacter() {
if (escapeCharacter == null) {
escapeCharacter = buildNullExpression();
}
return escapeCharacter;
}
/**
* Returns the enum constant that represents the identifier.
*
* @return Either <b>LIKE</b> or <b>NOT LIKE</b>
*/
public String getIdentifier() {
return (notIdentifier != null) ? NOT_LIKE : LIKE;
}
/**
* Returns the {@link Expression} that represents the pattern value.
*
* @return The expression that was parsed representing the pattern value
*/
public Expression getPatternValue() {
if (patternValue == null) {
patternValue = buildNullExpression();
}
return patternValue;
}
/**
* {@inheritDoc}
*/
public JPQLQueryBNF getQueryBNF() {
return getQueryBNF(LikeExpressionBNF.ID);
}
/**
* Returns the {@link Expression} that represents the string expression.
*
* @return The expression that was parsed representing the string expression
*/
public Expression getStringExpression() {
if (stringExpression == null) {
stringExpression = buildNullExpression();
}
return stringExpression;
}
/**
* Determines whether the identifier <b>ESCAPE</b> was parsed.
*
* @return <code>true</code> if the identifier <b>ESCAPE</b> was parsed; <code>false</code> otherwise
*/
public boolean hasEscape() {
return escapeIdentifier != null;
}
/**
* Determines whether the escape character was parsed, which is either a single character or an
* input parameter.
*
* @return <code>true</code> if the escape character was parsed; <code>false</code> otherwise
*/
public boolean hasEscapeCharacter() {
return escapeCharacter != null &&
!escapeCharacter.isNull();
}
/**
* Determines whether the identifier <b>NOT</b> was parsed.
*
* @return <code>true</code> if the identifier <b>NOT</b> was parsed; <code>false</code> otherwise
*/
public boolean hasNot() {
return notIdentifier != null;
}
/**
* Determines whether the pattern value was parsed.
*
* @return <code>true</code> if the pattern value was parsed; <code>false</code> otherwise
*/
public boolean hasPatternValue() {
return patternValue != null &&
!patternValue.isNull();
}
/**
* Determines whether a whitespace was parsed after <b>ESCAPE</b>.
*
* @return <code>true</code> if there was a whitespace after <b>ESCAPE</b>; <code>false</code> otherwise
*/
public boolean hasSpaceAfterEscape() {
return hasSpaceAfterEscape;
}
/**
* Determines whether a whitespace was parsed after <b>LIKE</b>.
*
* @return <code>true</code> if there was a whitespace after <b>LIKE</b>; <code>false</code> otherwise
*/
public boolean hasSpaceAfterLike() {
return hasSpaceAfterLike;
}
/**
* Determines whether a whitespace was parsed after the pattern value.
*
* @return <code>true</code> if there was a whitespace after the pattern value; <code>false</code> otherwise
*/
public boolean hasSpaceAfterPatternValue() {
return hasSpaceAfterPatternValue;
}
/**
* Determines whether a whitespace was parsed after the string expression.
*
* @return <code>true</code> if there was a whitespace after the string expression;
* <code>false</code> otherwise
*/
public boolean hasSpaceAfterStringExpression() {
return hasStringExpression();
}
/**
* Determines whether the string expression was parsed.
*
* @return <code>true</code> if the string expression was parsed; <code>false</code> otherwise
*/
public boolean hasStringExpression() {
return stringExpression != null &&
!stringExpression.isNull();
}
/**
* {@inheritDoc}
*/
@Override
protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
char character = word.charAt(0);
if (getQueryBNF(PatternValueBNF.ID).handleAggregate() &&
(character == '+' || character == '-' || character == '*' || character == '/')) {
return false;
}
return super.isParsingComplete(wordParser, word, expression) ||
word.equalsIgnoreCase(ESCAPE) ||
word.equalsIgnoreCase(AND) ||
word.equalsIgnoreCase(OR) ||
expression != null;
}
/**
* {@inheritDoc}
*/
@Override
protected void parse(WordParser wordParser, boolean tolerant) {
// Parse 'NOT
if (wordParser.startsWithIgnoreCase('N')) {
notIdentifier = wordParser.moveForward(NOT);
wordParser.skipLeadingWhitespace();
}
// Parse 'LIKE'
likeIdentifier = wordParser.moveForward(LIKE);
hasSpaceAfterLike = wordParser.skipLeadingWhitespace() > 0;
// Parse the pattern value
patternValue = parse(wordParser, PatternValueBNF.ID, tolerant);
int count = wordParser.skipLeadingWhitespace();
// Parse 'ESCAPE'
if (wordParser.startsWithIdentifier(ESCAPE)) {
hasSpaceAfterPatternValue = (count > 0);
count = 0;
escapeIdentifier = wordParser.moveForward(ESCAPE);
hasSpaceAfterEscape = wordParser.skipLeadingWhitespace() > 0;
}
else if (tolerant) {
hasSpaceAfterPatternValue = (count > 0);
}
else {
wordParser.moveBackward(count);
return;
}
// Parse escape character
char character = wordParser.character();
// Single escape character
if (character == SINGLE_QUOTE) {
escapeCharacter = new StringLiteral(this, wordParser.word());
escapeCharacter.parse(wordParser, tolerant);
count = 0;
}
// Parse input parameter
else if (ExpressionTools.isParameter(character)) {
escapeCharacter = new InputParameter(this, wordParser.word());
escapeCharacter.parse(wordParser, tolerant);
count = 0;
}
// Parse with the BNF
else {
escapeCharacter = parse(wordParser, LikeExpressionEscapeCharacterBNF.ID, tolerant);
if ((escapeIdentifier == null) &&
(escapeCharacter == null) &&
!wordParser.isTail()) {
hasSpaceAfterPatternValue = false;
wordParser.moveBackward(count);
}
}
}
/**
* {@inheritDoc}
*/
@Override
protected void toParsedText(StringBuilder writer, boolean actual) {
// String expression
if (stringExpression != null) {
stringExpression.toParsedText(writer, actual);
writer.append(SPACE);
}
// 'NOT LIKE' or 'LIKE'
if (actual) {
if (notIdentifier != null) {
writer.append(notIdentifier);
writer.append(SPACE);
}
writer.append(likeIdentifier);
}
else {
writer.append((notIdentifier != null) ? NOT_LIKE : LIKE);
}
if (hasSpaceAfterLike) {
writer.append(SPACE);
}
// Pattern value
if (patternValue != null) {
patternValue.toParsedText(writer, actual);
}
if (hasSpaceAfterPatternValue) {
writer.append(SPACE);
}
// 'ESCAPE'
if (escapeIdentifier != null) {
writer.append(actual ? escapeIdentifier : ESCAPE);
}
if (hasSpaceAfterEscape) {
writer.append(SPACE);
}
// Escape character
if (escapeCharacter != null) {
escapeCharacter.toParsedText(writer, actual);
}
}
}