/**
 *
 */
package de.intevation.gnv.action.sessionmodel;

import javax.servlet.http.HttpServletRequest;

import org.apache.log4j.Logger;

/**
 * @author Tim Englich <tim.englich@intevation.de>
 *
 */
public class SessionModelFactory {
    
    public final static String SESSION_MODEL_ID = "de.intevation.gnv.action.sessionmodel.SessionModel.ID";
    /**
     * the logger, used to log exceptions and additonaly information
     */
    private static Logger log = Logger.getLogger(SessionModelFactory.class);

    
    /**
     * The singleton Instance of this Factory.
     */
    private static SessionModelFactory instance = null;

    /**
     * Constructor
     */
    private SessionModelFactory() {
        super();
    }

    /**
     * This Method provides an singleton Instance of this Class.
     * @return an singleton Instance of this Class
     */
    public static SessionModelFactory getInstance(){
        if (instance == null){
            instance = new SessionModelFactory();
        }
        return instance;
    }
    
    
    /**
     * Getting the ArtifactDatabaseClient
     * @return the ArtifactDatabaseClient
     */
    public SessionModel getSessionModel(HttpServletRequest request){
       synchronized (this.getClass()) {
            SessionModel sm = null;
            if (request.getSession().getAttribute(SESSION_MODEL_ID)!= null){
                sm = (SessionModel)request.getSession().getAttribute(SESSION_MODEL_ID);
                ;
            }else{
                sm = new DefaultSessionModel();
                request.getSession().setAttribute(SESSION_MODEL_ID, sm);
            }
            
            return sm;
       }
    }

}