contextsessionlistener.java

来自「Java的面向对象数据库系统的源代码」· Java 代码 · 共 170 行

// $Id: ContextSessionListener.java,v 1.1 2002/07/18 09:08:03 per_nyfelt Exp $

package webapp;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.ServletContextAttributeListener;
import javax.servlet.ServletContextAttributeEvent;
import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

import org.apache.log4j.Category;

import webapp.WebApp;


/**
 * Listener for context-related and session-related application
 * events. Controls the state of the "WebApp" (which manages
 * "application global" objects like the database connection).
 *
 * @author James Stiefel
 * @version $Revision: 1.1 $ $Date: 2002/07/18 09:08:03 $
 */

public final class ContextSessionListener
    implements ServletContextListener, ServletContextAttributeListener,
                HttpSessionAttributeListener, HttpSessionListener {
    /**
     * log4j logger
     */
    private static Category logger = Category.getInstance(ContextSessionListener.class.getName());

    /**
     * Initialize the application and store in the context.
     *
     * @param event The servlet context event
     */
    public void contextInitialized(ServletContextEvent event) {

        logger.info("contextInitialized()");

        try {

            WebApp.init();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * Clean up and close down the application
     *
     * @param event The servlet context event
     */
    public void contextDestroyed(ServletContextEvent event) {

        logger.info("contextDestroyed()");

        //close down the app
        try {

            // close the database connection
            WebApp.term();

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    /**
     * Record the fact that a servlet context attribute was added.
     *
     * @param event The servlet context attribute event
     */
    public void attributeAdded(ServletContextAttributeEvent event) {

        logger.info("attributeAdded('" + event.getName() + "', '" +
            event.getValue() + "')");
    }

    /**
     * Record the fact that a servlet context attribute was removed.
     *
     * @param event The servlet context attribute event
     */
    public void attributeRemoved(ServletContextAttributeEvent event) {

        logger.info("attributeRemoved('" + event.getName() + "', '" +
            event.getValue() + "')");
    }

    /**
     * Record the fact that a servlet context attribute was replaced.
     *
     * @param event The servlet context attribute event
     */
    public void attributeReplaced(ServletContextAttributeEvent event) {

        logger.info("attributeReplaced('" + event.getName() + "', '" +
            event.getValue() + "')");

    }

    /**
     * Record the fact that a servlet session attribute was added.
     *
     * @param event The session attribute event
     */
    public void attributeAdded(HttpSessionBindingEvent event) {

        logger.info("attributeAdded('" + event.getSession().getId() + "', '" +
            event.getName() + "', '" + event.getValue() + "')");
    }


    /**
     * Record the fact that a servlet session attribute was removed.
     *
     * @param event The session attribute event
     */
    public void attributeRemoved(HttpSessionBindingEvent event) {

        logger.info("attributeRemoved('" + event.getSession().getId() + "', '" +
            event.getName() + "', '" + event.getValue() + "')");
    }


    /**
     * Record the fact that a servlet context attribute was replaced.
     *
     * @param event The session attribute event
     */
    public void attributeReplaced(HttpSessionBindingEvent event) {

        logger.info("attributeReplaced('" + event.getSession().getId() + "', '" +
            event.getName() + "', '" + event.getValue() + "')");
    }




    /**
     * Record the fact that a session has been created.
     *
     * @param event The session event
     */
    public void sessionCreated(HttpSessionEvent event) {

        logger.info("sessionCreated('" + event.getSession().getId() + "')");
    }


    /**
     * Record the fact that a session has been destroyed.
     *
     * @param event The session event
     */
    public void sessionDestroyed(HttpSessionEvent event) {

        logger.info("sessionDestroyed('" + event.getSession().getId() + "')");

    }

}