examples/Vlib/src/net/sf/tapestry/vlib/Visit.java

/*
 *  ====================================================================
 *  The Apache Software License, Version 1.1
 *
 *  Copyright (c) 2002 The Apache Software Foundation.  All rights
 *  reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *  notice, this list of conditions and the following disclaimer.
 *
 *  2. Redistributions in binary form must reproduce the above copyright
 *  notice, this list of conditions and the following disclaimer in
 *  the documentation and/or other materials provided with the
 *  distribution.
 *
 *  3. The end-user documentation included with the redistribution,
 *  if any, must include the following acknowledgment:
 *  "This product includes software developed by the
 *  Apache Software Foundation (http://www.apache.org/)."
 *  Alternately, this acknowledgment may appear in the software itself,
 *  if and wherever such third-party acknowledgments normally appear.
 *
 *  4. The names "Apache" and "Apache Software Foundation" and
 *  "Apache Tapestry" must not be used to endorse or promote products
 *  derived from this software without prior written permission. For
 *  written permission, please contact apache@apache.org.
 *
 *  5. Products derived from this software may not be called "Apache",
 *  "Apache Tapestry", nor may "Apache" appear in their name, without
 *  prior written permission of the Apache Software Foundation.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 *  ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 *  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 *  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 *  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 *  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *  ====================================================================
 *
 *  This software consists of voluntary contributions made by many
 *  individuals on behalf of the Apache Software Foundation.  For more
 *  information on the Apache Software Foundation, please see
 *  <http://www.apache.org/>.
 */
package net.sf.tapestry.vlib;

import java.io.Serializable;
import java.rmi.RemoteException;
import java.sql.Timestamp;

import javax.ejb.FinderException;

import net.sf.tapestry.ApplicationRuntimeException;
import net.sf.tapestry.vlib.ejb.Person;

/**
 *  The visit object for the {@link VirtualLibraryEngine}.
 *
 *  Primarily, this is used to access the home interfaces and EJB instances, and
 *  to identify who the logged in user is.
 *
 *
 *  @author Howard Lewis Ship
 *  @version $Id$
 *
 **/

public class Visit implements Serializable
{
    /**
     *  Used to identify the logged in user.
     *
     **/

    private transient Person _user;
    private Integer _userPK;

    /**
     *  Set when the user first logs in.  This is the time of their previous
     *  login (logging in returns the old value then updates the value
     *  for subsequent logins).
     *
     **/

    private Timestamp _lastAccess;

    private VirtualLibraryEngine _engine;

    public Visit(VirtualLibraryEngine engine)
    {
        _engine = engine;
    }

    public VirtualLibraryEngine getEngine()
    {
        return _engine;
    }

    /**
     *  Returns the time the user last accessed the database, which may
     *  be null if the user hasn't logged in yet.
     *
     **/

    public Timestamp getLastAccess()
    {
        return _lastAccess;
    }

    /**
     *  Gets the logged-in user, or null if the user is not logged in.
     *
     **/

    public Person getUser()
    {
        if (_user != null)
            return _user;

        if (_userPK == null)
            return null;

        for (int i = 0; i < 2; i++)
        {
            try
            {
                _user = _engine.getOperations().getPerson(_userPK);

                break;
            }
            catch (FinderException e)
            {
                throw new ApplicationRuntimeException("Could not locate user.", e);
            }
            catch (RemoteException ex)
            {
                _engine.rmiFailure("Unable to access logged-in user.", ex, i > 0);
            }
        }

        return _user;
    }

    /**
     *  Returns the primary key of the logged in user, or null if the
     *  user is not logged in.
     *
     **/

    public Integer getUserPK()
    {
        return _userPK;
    }

    /**
     *  Changes the logged in user. This is only invoked from the 
     *  {@link net.sf.tapestry.vlib.pages.Login} page.
     *
     **/

    public void setUser(Person value)
    {
        _lastAccess = null;
        _user = value;
        _userPK = null;

        if (_user == null)
            return;

        _userPK = _user.getPrimaryKey();

        _lastAccess = _user.getLastAccess();
    }

    /**
     *  Returns true if the user is logged in.
     *
     **/

    public boolean isUserLoggedIn()
    {
        return _userPK != null;
    }

    /**
     *  Returns true if the user has not been identified (has not
     *  logged in).
     *
     **/

    public boolean isUserLoggedOut()
    {
        return _userPK == null;
    }

    public boolean isLoggedInUser(Integer primaryKey)
    {
        if (_userPK == null)
            return false;

        return _userPK.equals(primaryKey);
    }

    /**
     *  Invoked by pages after they perform an operation that changes the backend
     *  database in such a way that cached data is no longer valid.  Currently,
     *  this should be invoked after changing the user's profile, or adding
     *  a new {@link net.sf.tapestry.vlib.ejb.IPublisher} entity.
     *
     **/

    public void clearCache()
    {
        _user = null;

        _engine.clearCache();
    }

}