/* ================================================================

 * Cewolf : Chart enabling Web Objects Framework

 * ================================================================

 *

 * Project Info:  http://cewolf.sourceforge.net

 * Project Lead:  Guido Laures (guido@laures.de);

 *

 * (C) Copyright 2002, by Guido Laures

 *

 * This library 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 2.1 of the License, or (at your option) any later version.

 *

 * This library 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 this

 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,

 * Boston, MA 02111-1307, USA.

 */

package de.laures.cewolf;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpSession;

import javax.servlet.jsp.PageContext;

/**

 * Pluggable storage. Implement this class to change the

 * storage concept which Cewolf uses to store chart imanges and

 * provide the implementation class name as init paramter <em>storage</em>

 * for Cewolf servlet.

 * @author glaures

 */

public interface Storage{

	/**

	 * Stores a chart image.

	 * @param cid the image to be stored

	 * @param servletContext servletContext which might be needed

	 * @return String the storage id which is used to find the image in storage

	 */

	public String storeChartImage(ChartImage chartImage, PageContext pageContext) throws CewolfException;

	/**

	 * Retrieves a chart image.

	 * @param id the id of the image

	 * @param request the request

	 * @return ChartImage the stored image instance

	 */

	public ChartImage getChartImage(String id, HttpServletRequest request);

	/**

	 * Tests if a chart image is already available in thsi store..

	 * @param chartImage the image to test

	 * @param pageContext the pageContext

	 * @return <code>true</code> if a stored instance of this image is availbale

	 */

	// public boolean contains(ChartImage chartImage, PageContext pageContext);

	/**

	 * Returns the key for this 

	 * @param chartImage

	 * @return String

	 */

	// public String getKey(ChartImage chartImage);

	/**

	 * Method init.

	 * @param servletContext

	 * @throws CewolfException

	 */

	public void init(ServletContext servletContext) throws CewolfException;

	/**

	 * Removes the image from the storage

	 * @param imgId Image id

	 * @param request Servlet request

	 * @return Image id

	 * @throws CewolfException

	 */

	public String removeChartImage(String imgId, HttpServletRequest request)

			throws CewolfException;

}