SessionManager.java

/***************************************************
*
* cismet GmbH, Saarbruecken, Germany
*
*              ... and it just works.
*
****************************************************/
package Sirius.navigator.connection;

import Sirius.navigator.connection.proxy.*;

import org.apache.log4j.*;

import de.cismet.tools.CurrentStackTrace;

/**
 * DOCUMENT ME!
 *
 * @version  $Revision$, $Date$
 */
public final class SessionManager {

    //~ Static fields/initializers ---------------------------------------------

    private static final Logger logger = Logger.getLogger(SessionManager.class);
    private static SessionManager manager = null;
    private static double nonce = Math.random();
    private static final Object blocker = new Object();

    //~ Instance fields --------------------------------------------------------

    private ConnectionProxy proxy;

    //~ Constructors -----------------------------------------------------------

    /**
     * Creates a new SessionManager object.
     *
     * @param  proxy  DOCUMENT ME!
     */
    private SessionManager(final ConnectionProxy proxy) {
        this.proxy = proxy;
        if (logger.isInfoEnabled()) {
            logger.info("singleton shared instance of SessionManager created"); // NOI18N
        }
    }

    //~ Methods ----------------------------------------------------------------

    /**
     * DOCUMENT ME!
     *
     * @param  proxy  DOCUMENT ME!
     */
    public static void init(final ConnectionProxy proxy) {
        if (logger.isDebugEnabled()) {
            logger.debug("init SessionManager " + nonce, new CurrentStackTrace()); // NOI18N
        }
        synchronized (blocker) {
            if (manager == null) {
                manager = new SessionManager(proxy);
            } else {
                manager.proxy = proxy;
                logger.warn("SessionManager has already been initialized");        // NOI18N
                // throw new RuntimeException("SessionManager has alreadyt been initialized");
            }
        }
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     */
    public static boolean isInitialized() {
        synchronized (blocker) {
            return manager != null;
        }
    }

    /**
     * DOCUMENT ME!
     */
    public static void destroy() {
        if (logger.isInfoEnabled()) {
            logger.info("destroy SessionManager" + manager, new CurrentStackTrace()); // NOI18N
        }
        synchronized (blocker) {
            logger.warn("destroying singelton SessionManager instance");              // NOI18N
//            manager = null;
        }
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     */
    public static boolean isConnected() {
        if (manager == null) {
            return false;
        } else {
            return getManager().proxy.isConnected();
        }
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     */
    public static boolean onClientSide() {
        return isConnected();
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     *
     * @throws  RuntimeException  DOCUMENT ME!
     */
    private static SessionManager getManager() {
        if (manager == null) {
            final Throwable t = new CurrentStackTrace();
            logger.warn("SessionManager has not been initialized", t);                // NOI18N
            throw new RuntimeException("SessionManager has not been initialized", t); // NOI18N
        }

        return manager;
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     */
    public static Connection getConnection() {
        try {
            return getManager().proxy.getSession().getConnection();
        } catch (Exception e) {
            logger.error("Error in getConnection()\nmaybe the manager is null" + getManager(), e); // NOI18N
        }
        return null;
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     */
    public static ConnectionSession getSession() {
        return getManager().proxy.getSession();
    }

    /**
     * DOCUMENT ME!
     *
     * @return  DOCUMENT ME!
     */
    public static ConnectionProxy getProxy() {
        return getManager().proxy;
    }
}