/*
* org.openmicroscopy.shoola.env.data.login.LoginManager
*
*------------------------------------------------------------------------------
* Copyright (C) 2006 University of Dundee. All rights reserved.
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*------------------------------------------------------------------------------
*/
package org.openmicroscopy.shoola.env.data.login;
//Java imports
//Third-party libraries
//Application-internal dependencies
import org.openmicroscopy.shoola.env.event.AgentEvent;
/**
* Decorates a {@link LoginService} to add thread-safety.
*
* @author Jean-Marie Burel
* <a href="mailto:j.burel@dundee.ac.uk">j.burel@dundee.ac.uk</a>
* @author <br>Andrea Falconi
* <a href="mailto:a.falconi@dundee.ac.uk">
* a.falconi@dundee.ac.uk</a>
* @version 2.2
* <small>
* (<b>Internal version:</b> $Revision$ $Date$)
* </small>
* @since OME2.2
*/
public class LoginManager
implements LoginService
{
/** The service's logic. */
private LoginService service;
/**
* Creates a new instance to decorate the given Login Service in order to
* obtain a thread-safe service.
*
* @param service The actual Login Service. Mustn't be <code>null</code>.
*/
public LoginManager(LoginService service)
{
if (service == null) throw new NullPointerException("No service.");
this.service = service;
}
/**
* Implemented as specified by the {@link LoginService} interface.
* @see LoginService#getState()
*/
public synchronized int getState() { return service.getState(); }
/**
* Implemented as specified by the {@link LoginService} interface.
* @see LoginService#login()
*/
public synchronized void login()
{
if (service.getState() == IDLE) service.login();
//Else another thread has already hit this method, the Login Service
//has attempted to connect but failed and brought up the Login dialog.
//So it's now waiting for the user to enter their credentials. The
//Login dialog will call login(UserCredentials) when the credentials
//have been entered. So this thread can just return because an attempt
//is already ongoing.
//Note that we can assert this because *both* login methods acquire the
//same lock and the login(UserCredentials) always leaves the state to
//IDLE upon return.
}
/**
* Implemented as specified by the {@link LoginService} interface.
* @see LoginService#login(UserCredentials)
*/
public synchronized int login(UserCredentials uc)
{
if (service.getState() == IDLE) return service.login(uc);
return NOT_CONNECTED;
}
/**
* Implemented as specified by the {@link LoginService} interface.
* @see LoginService#eventFired(AgentEvent)
*/
public synchronized void eventFired(AgentEvent serviceActivationRequest)
{
service.eventFired(serviceActivationRequest);
}
/**
* Implemented as specified by the {@link LoginService} interface.
* @see LoginService#notifyLoginFailure()
*/
public void notifyLoginFailure() { service.notifyLoginFailure(); }
/**
* Implemented as specified by the {@link LoginService} interface.
* @see LoginService#notifyLoginTimeout()
*/
public void notifyLoginTimeout() { service.notifyLoginTimeout(); }
//NOTE: We do need to acquire the lock here, even though this method is
//only called within the UI thread. The reason is that we need to make
//sure that working memories are flushed -- this is a side-effect of
//acquiring the lock. In fact, if another thread has called login() and
//the attempt was successful, then the connected field in the OMEDSGateway
//will be set to true. Later on when the UI thread calls this method, we
//want to be sure that the connected field has been flushed and so is
//visible to the UI thread. In fact, the implementation of eventFired()
//queries (indirectly) the connected field to find out if there's a valid
//link to OMEDS.
}