/*
 * Copyright (c) 2001-2007 Sun Microsystems, Inc.  All rights reserved.
 *  
 *  The Sun Project JXTA(TM) Software License
 *  
 *  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 Sun Microsystems, Inc. for JXTA(TM) technology." 
 *     Alternately, this acknowledgment may appear in the software itself, if 
 *     and wherever such third-party acknowledgments normally appear.
 *  
 *  4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must 
 *     not be used to endorse or promote products derived from this software 
 *     without prior written permission. For written permission, please contact 
 *     Project JXTA at http://www.jxta.org.
 *  
 *  5. Products derived from this software may not be called "JXTA", nor may 
 *     "JXTA" appear in their name, without prior written permission of Sun.
 *  
 *  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 SUN 
 *  MICROSYSTEMS 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.
 *  
 *  JXTA is a registered trademark of Sun Microsystems, Inc. in the United 
 *  States and other countries.
 *  
 *  Please see the license information page at :
 *  <http://www.jxta.org/project/www/license.html> for instructions on use of 
 *  the license in source files.
 *  
 *  ====================================================================
 *  
 *  This software consists of voluntary contributions made by many individuals 
 *  on behalf of Project JXTA. For more information on Project JXTA, please see 
 *  http://www.jxta.org.
 *  
 *  This license is based on the BSD license adopted by the Apache Foundation. 
 */

package net.jxta.impl.membership.pse;


import net.jxta.exception.PeerGroupException;
import net.jxta.impl.protocol.PSEConfigAdv;


/**
 *
 * @author nick
 */
public abstract class PSEAuthenticatorEngineFactory {
    
    private static PSEAuthenticatorEngineFactory defaultEngine = null;
    
    public static void setPSESecurityEngineFactory(PSEAuthenticatorEngineFactory newEngine) {
        synchronized (PSEAuthenticatorEngineFactory.class) {
            defaultEngine = newEngine;
        }
    }
    
    /**
     *   Returns the default Authenticator Engine.
     *
     *   @return The current default Authenticator Engine.
     **/
    public static PSEAuthenticatorEngineFactory getDefault() {
        synchronized (PSEAuthenticatorEngineFactory.class) {
            if (defaultEngine == null) {
                defaultEngine = new PSEAuthenticatorEngineDefaultFactory();
            }
            
            return defaultEngine;
        }
    }
    
    /**
     *   Creates a new Authenticator Engine instance based upon the context and configuration.
     *
     *   @param service  The service that this keystore manager will be working for.
     *   @param config   The configuration parameters.
     **/
    public abstract PSEAuthenticatorEngine getInstance(PSEMembershipService service, PSEConfigAdv config) throws PeerGroupException;
    
    /**
     *   Default implementation which provides the default behaviour (which is to do nothing).
     **/
    private static class PSEAuthenticatorEngineDefaultFactory extends PSEAuthenticatorEngineFactory {

        @Override
        public PSEAuthenticatorEngine getInstance(PSEMembershipService service, PSEConfigAdv config) throws PeerGroupException {
            return null;
        }
    }
}