StringLiteral.java

/*******************************************************************************
 * 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.ExpressionTools;
import org.eclipse.persistence.jpa.jpql.WordParser;

/**
 * A string literal is enclosed in single quotes. For example: 'literal'. A string literal that
 * includes a single quote is represented by two single quotes. For example: 'literal''s'. String
 * literals in queries, like Java String literals, use unicode character encoding. Approximate
 * literals support the use Java floating point literal syntax as well as SQL approximate numeric
 * literal syntax. Enum literals support the use of Java enum literal syntax. The enum class name
 * must be specified. Appropriate suffixes may be used to indicate the specific type of a numeric
 * literal in accordance with the Java Language Specification. The boolean literals are <code>TRUE</code>
 * and <code>FALSE</code>. Although predefined reserved literals appear in upper case, they are case
 * insensitive.
 *
 * @version 2.4
 * @since 2.3
 * @author Pascal Filion
 */
public final class StringLiteral extends AbstractExpression {

    /**
     * Caches the value indicating if the string literal has the closing quote.
     */
    private Boolean hasCloseQuote;

    /**
     * Creates a new <code>StringLiteral</code>.
     *
     * @param parent The parent of this expression
     * @param literal The string literal
     */
    public StringLiteral(AbstractExpression parent, String literal) {
        super(parent, literal);
    }

    /**
     * {@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()));
    }

    /**
     * {@inheritDoc}
     */
    public JPQLQueryBNF getQueryBNF() {
        return getQueryBNF(StringLiteralBNF.ID);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getText() {
        return super.getText();
    }

    /**
     * Returns the string literal without the single quotes.
     *
     * @return The unquoted text
     */
    public String getUnquotedText() {
        return ExpressionTools.unquote(getText());
    }

    /**
     * Determines whether the closing quote was present or not.
     *
     * @return <code>true</code> if the literal is ended by a single quote; <code>false</code>
     * otherwise
     */
    public boolean hasCloseQuote() {
        if (hasCloseQuote == null) {
            String text = getText();
            int length = text.length();
            hasCloseQuote = (length > 1) && ExpressionTools.isQuote(text.charAt(length - 1));
        }
        return hasCloseQuote;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void parse(WordParser wordParser, boolean tolerant) {
        wordParser.moveForward(getText());
    }

    /**
     * {@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(getText());
    }
}