de.laures.cewolf.storage.AbstractSessionStorage.java Source code

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Here is the source code for de.laures.cewolf.storage.AbstractSessionStorage.java

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/* ================================================================
 * 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.Serializable;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import javax.servlet.jsp.PageContext;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import de.laures.cewolf.CewolfException;
import de.laures.cewolf.ChartImage;
import de.laures.cewolf.Storage;
import de.laures.cewolf.taglib.util.KeyGenerator;

/**
 * @author glaures
 */
public abstract class AbstractSessionStorage implements Storage {

    private static final Log log = LogFactory.getLog(AbstractSessionStorage.class);

    /**
     * @see de.laures.cewolf.Storage#storeChartImage(ChartImage, ServletContext)
     */
    public String storeChartImage(ChartImage cid, PageContext pageContext) throws CewolfException {
        if (contains(cid, pageContext)) {
            return getKey(cid);
        }
        log.debug("storing chart " + cid);
        final HttpSession session = pageContext.getSession();
        //String key = getKey(cid);
        return storeChartImage(cid, session);
    }

    /**
     * @see de.laures.cewolf.Storage#getChartImage(String)
     */
    public ChartImage getChartImage(String id, HttpServletRequest request) {
        HttpSession session = request.getSession();
        return (ChartImage) session.getAttribute(id);
    }

    public boolean contains(ChartImage cid, PageContext pageContext) {
        return pageContext.getSession().getAttribute(getKey(cid)) != null;
    }

    public final String getKey(ChartImage cid) {
        return String.valueOf(KeyGenerator.generateKey((Serializable) cid));
    }

    protected String storeChartImage(ChartImage cid, HttpSession session) throws CewolfException {
        final String sessionKey = getKey(cid);
        synchronized (session) {
            session.setAttribute(sessionKey, getCacheObject(cid));
        }
        return sessionKey;
    }

    /**
     */
    public String removeChartImage(String imgKey, HttpServletRequest request) throws CewolfException {
        final HttpSession session = request.getSession();
        if (session == null) {
            return imgKey;
        }
        return removeChartImage(imgKey, session);
    }

    /**
     * @param cid
     * @param session
     * @return
     * @throws CewolfException
     */
    protected String removeChartImage(String cid, HttpSession session) throws CewolfException {
        synchronized (session) {
            session.removeAttribute(cid);
        }
        return cid;
    }

    protected abstract Object getCacheObject(ChartImage cid) throws CewolfException;

    /**
     * @see de.laures.cewolf.Storage#init(ServletContext)
     */
    public void init(ServletContext servletContext) throws CewolfException {
    }

}