/*
 * JasperReports - Free Java Reporting Library.
 * Copyright (C) 2001 - 2009 Jaspersoft Corporation. All rights reserved.
 * http://www.jaspersoft.com
 *
 * Unless you have purchased a commercial license agreement from Jaspersoft,
 * the following license terms apply:
 *
 * This program is part of JasperReports.
 *
 * JasperReports is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * JasperReports is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with JasperReports. If not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Contributors:
 * Eugene D - eugenedruy@users.sourceforge.net 
 * Adrian Jackson - iapetus@users.sourceforge.net
 * David Taylor - exodussystems@users.sourceforge.net
 * Lars Kristensen - llk@users.sourceforge.net
 */
package net.sf.jasperreports.engine.util;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import net.sf.jasperreports.engine.JRExpression;
import net.sf.jasperreports.engine.JRExpressionChunk;


/**
 * @author Teodor Danciu (teodord@users.sourceforge.net)
 * @version $Id: JRExpressionUtil.java 3712 2010-04-08 09:53:09Z teodord $
 */
public final class JRExpressionUtil
{

	
	/**
	 *
	 */
	public static String getExpressionText(JRExpression exp)
	{
		return exp == null ? null : exp.getText();
	}


	private static final Pattern SIMPLE_EXPRESSION_PATTERN = 
		Pattern.compile("\\s*\"([^\"]*((?<=\\\\)\"[^\"]*)*)\"\\s*");
	
	private static final int SIMPLE_EXPRESSION_TEXT_GROUP = 1;
	
	private static final Pattern TEXT_QUOTE_PATTERN = Pattern.compile("\\\\\"");
	private static final String TEXT_QUOTE_REPLACEMENT = "\"";
	
	/**
	 *
	 */
	public static String getSimpleExpressionText(JRExpression expression)
	{
		String value = null;
		if (expression != null)
		{
			JRExpressionChunk[] chunks = expression.getChunks();
			if (
				chunks != null 
				&& chunks.length == 1 
				&& chunks[0].getType() == JRExpressionChunk.TYPE_TEXT
				)
			{
				String chunk = chunks[0].getText();
				Matcher matcher = SIMPLE_EXPRESSION_PATTERN.matcher(chunk);
				if (matcher.matches())
				{
					String text = matcher.group(SIMPLE_EXPRESSION_TEXT_GROUP);
					value = TEXT_QUOTE_PATTERN.matcher(text).replaceAll(
							TEXT_QUOTE_REPLACEMENT);
				}
			}
		}
		return value;
	}


	private JRExpressionUtil()
	{
	}
}
