/*******************************************************************************
* 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.List;
import org.eclipse.persistence.jpa.jpql.WordParser;
/**
* This {@link Expression} represents a date or time. It supports the following identifiers:
* <p>
* <b>CURRENT_DATE</b>: This function returns the value of current date on the database server.
* <p>
* <b>CURRENT_TIME</b>: This function returns the value of current time on the database server.
* <p>
* <b>CURRENT_TIMESTAMP</b>: This function returns the value of current timestamp on the database
* server.
*
* <div><b>BNF:</b> <code>functions_returning_datetime ::= CURRENT_DATE | CURRENT_TIME | CURRENT_TIMESTAMP</code></div>
* <p>
* The JDBC escape syntax may be used for the specification of date, time, and timestamp literals.
*
* <div><b>BNF:</b> <code>expression ::= {d 'yyyy-mm-dd'} | {t 'hh:mm:ss'} | {ts 'yyyy-mm-dd hh:mm:ss.f...'}</code><p></div>
*
* @version 2.4
* @since 2.3
* @author Pascal Filion
*/
public final class DateTime extends AbstractExpression {
/**
* The actual identifier found in the string representation of the JPQL query.
*/
private String identifier;
/**
* Creates a new <code>DateTime</code>.
*
* @param parent The parent of this expression
*/
public DateTime(AbstractExpression parent) {
super(parent);
}
/**
* {@inheritDoc}
*/
public void accept(ExpressionVisitor visitor) {
visitor.visit(this);
}
/**
* {@inheritDoc}
*/
public void acceptChildren(ExpressionVisitor visitor) {
}
/**
* {@inheritDoc}
*/
@Override
protected void addOrderedChildrenTo(List<Expression> children) {
children.add(buildStringExpression(getText()));
}
/**
* 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 identifier;
}
/**
* {@inheritDoc}
*/
public JPQLQueryBNF getQueryBNF() {
return getQueryBNF(FunctionsReturningDatetimeBNF.ID);
}
/**
* {@inheritDoc}
*/
@Override
public String getText() {
return super.getText();
}
/**
* Determines whether this {@link DateTime} represents the JPQL identifier
* {@link Expression#CURRENT_DATE CURRENT_DATE}.
*
* @return <code>true</code> if this {@link Expression} represents
* {@link Expression#CURRENT_DATE CURRENT_DATE}; <code>false</code> otherwise
*/
public boolean isCurrentDate() {
return getText() == CURRENT_DATE;
}
/**
* Determines whether this {@link DateTime} represents the JPQL identifier
* {@link Expression#CURRENT_TIME CURRENT_TIME}.
*
* @return <code>true</code> if this {@link Expression} represents
* {@link Expression#CURRENT_TIME CURRENT_TIME}; <code>false</code> otherwise
*/
public boolean isCurrentTime() {
return getText() == CURRENT_TIME;
}
/**
* Determines whether this {@link DateTime} represents the JPQL identifier
* {@link Expression#CURRENT_TIMESTAMP CURRENT_TIMESTAMP}.
*
* @return <code>true</code> if this {@link Expression} represents
* {@link Expression#CURRENT_TIMESTAMP CURRENT_TIMESTAMP}; <code>false</code>
* otherwise
*/
public boolean isCurrentTimestamp() {
return getText() == CURRENT_TIMESTAMP;
}
/**
* Determines whether this {@link DateTime} represents the JDBC escape syntax for date, time,
* timestamp formats.
*
* @return <code>true</code> if this {@link Expression} represents a JDBC escape syntax;
* <code>false</code> otherwise
*/
public boolean isJDBCDate() {
return getText().charAt(0) == LEFT_CURLY_BRACKET;
}
/**
* {@inheritDoc}
*/
@Override
protected void parse(WordParser wordParser, boolean tolerant) {
// JDBC escape format for date/time/timestamp
if (wordParser.startsWith(LEFT_CURLY_BRACKET)) {
parseJDBCEscapeFormat(wordParser);
}
// JPQL identifiers
else {
String identifier = parseIdentifier(wordParser);
setText(identifier);
this.identifier = wordParser.moveForward(identifier);
}
}
private String parseIdentifier(WordParser wordParser) {
int position = wordParser.position();
char character = wordParser.character(position + 8);
if (character == 'd' || character == 'D') {
return CURRENT_DATE;
}
character = wordParser.character(position + 12);
if (character == 's' || character == 'S') {
return CURRENT_TIMESTAMP;
}
return CURRENT_TIME;
}
private void parseJDBCEscapeFormat(WordParser wordParser) {
int startIndex = wordParser.position();
int stopIndex = startIndex + 1;
for (int index = startIndex + 1, length = wordParser.length(); index < length; index++) {
char character = wordParser.character(index);
if (character == RIGHT_CURLY_BRACKET) {
stopIndex = index + 1;
break;
}
stopIndex++;
}
setText(wordParser.substring(startIndex, stopIndex));
wordParser.moveForward(stopIndex - startIndex);
}
/**
* {@inheritDoc}
*/
@Override
public String toActualText() {
return getText();
}
/**
* {@inheritDoc}
*/
@Override
public String toParsedText() {
return getText();
}
/**
* {@inheritDoc}
*/
@Override
protected void toParsedText(StringBuilder writer, boolean actual) {
writer.append(actual && !isJDBCDate() ? identifier : getText());
}
}