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

 * 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.storage;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.Serializable;

import java.util.ArrayList;

import java.util.List;

import javax.servlet.ServletContext;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.jsp.PageContext;

import de.laures.cewolf.CewolfException;

import de.laures.cewolf.ChartImage;

import de.laures.cewolf.Configuration;

import de.laures.cewolf.Storage;

import de.laures.cewolf.taglib.util.KeyGenerator;

/**

 * Storage for storing images as files in the web application directory as files _chart-XXXXX.

 * Note that by default the files won't ever be removed. To remove saved images on VM exit set

 * the <code>FileStorage.deleteOnExit</code> configuration parameter to "true". For example:

 * 

 * <pre>

 *		<init-param>

 *			<param-name>storage</param-name>

 *			<param-value>de.laures.cewolf.storage.FileStorage</param-value>

 *		</init-param>

 *		<init-param>

 *				<param-name>FileStorage.deleteOnExit</param-name>

 *				<param-value>true</param-value>

 *		</init-param> 

 *	</pre> 

 * 

 * @author guido

 */

public class FileStorage implements Storage {

	String basePath = null;

	List stored = new ArrayList();

	private boolean deleteOnExit = false;

	/**

	 * @see de.laures.cewolf.Storage#storeChartImage(ChartImage, PageContext)

	 */

	public String storeChartImage(ChartImage cid, PageContext pageContext) {

		if(contains(cid, pageContext)){

			return getKey(cid);

		}

		String id = getKey(cid);

		ObjectOutputStream oos = null;

		try {

			String fileName = getFileName(id);

			pageContext.getServletContext().log("Storing image to file " + fileName);

			File f = new File(fileName);

			if (deleteOnExit) {

				f.deleteOnExit();			

			}

			oos = new ObjectOutputStream(new FileOutputStream(f));

			oos.writeObject(new SerializableChartImage(cid));

			oos.close();

		} catch(IOException ioex){

			ioex.printStackTrace();

		} catch(CewolfException cwex){

			cwex.printStackTrace();

		} finally {

			if(oos != null){

				try {

					oos.close();

				} catch(IOException ioex){

					ioex.printStackTrace();

				}

			}

		}

		return id;		

	}

	/**

	 * @see de.laures.cewolf.Storage#getChartImage(String, HttpServletRequest)

	 */

	public ChartImage getChartImage(String id, HttpServletRequest request) {

		ChartImage res = null;

		ObjectInputStream ois = null;

		try {

			ois = new ObjectInputStream(new FileInputStream(getFileName(id)));

			res = (ChartImage)ois.readObject();

			ois.close();

		} catch(Exception ex){

			ex.printStackTrace();

		} finally {

			if(ois != null){

				try {

					ois.close();

				} catch(IOException ioex){

					ioex.printStackTrace();

				}

			}

		}

		return res;

	}

	/**

	 * @see de.laures.cewolf.Storage#contains(ChartImage, PageContext)

	 */

	public boolean contains(ChartImage chartImage, PageContext pageContext) {

		return new File(getFileName(chartImage)).exists();

	}

	/**

	 * @see de.laures.cewolf.Storage#getKey(ChartImage)

	 */

	public String getKey(ChartImage chartImage) {

		return String.valueOf(KeyGenerator.generateKey((Serializable)chartImage));

	}

	/**

	 * @see de.laures.cewolf.Storage#init(ServletContext)

	 */

	public void init(ServletContext servletContext) throws CewolfException {

		basePath = servletContext.getRealPath("/");

		Configuration config = Configuration.getInstance(servletContext);

		deleteOnExit = "true".equalsIgnoreCase("" + config.getParameters().get("FileStorage.deleteOnExit"));

		servletContext.log("FileStorage initialized, deleteOnExit=" + deleteOnExit);

	}

	private String getFileName(ChartImage chartImage){

		return getFileName(getKey(chartImage));

	}

	private String getFileName(String id){

		return basePath + "_chart" + id;

	}

	/**

	 * @see de.laures.cewolf.Storage#removeChartImage(java.lang.String, javax.servlet.jsp.PageContext)

	 */

	public String removeChartImage(String imgKey, HttpServletRequest pageContext) throws CewolfException {

		File file = new File(getFileName(imgKey));

		if (file.exists())

		{

			if (!file.delete())

			{

				throw new CewolfException("Could not delete file " + file.getAbsolutePath());

			}

		}

		return imgKey;

	}

}