/*
 * 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.service;


import net.jxta.document.Advertisement;
import net.jxta.platform.Module;


/**
 * This interface implements the peer group service interface. Peer groups
 * are formed as a collection of peers that have agreed upon a common set of
 * services. The JXTA platform provides a predefined set of services to build
 * peer groups
 *
 * <p/>Every service is defined by a
 * {@link net.jxta.protocol.ModuleImplAdvertisement}. The Service
 * advertisement provides the necessary information to uniquely identify
 * the service and to contact its associated service(s).
 *
 * <p/>When a new peer is joining a peer group an instance of all the
 * services associated with the new peer group is created on this peer
 * dynamically. Not all services need to be resident on a peer. A peer can
 * dynamically load a new service from the peer it contacted to join the
 * new peer group (via the PeerGroupAdvertisement of this group).
 *
 * @see         net.jxta.peergroup.PeerGroup
 * @see         net.jxta.platform.Application
 * @see         net.jxta.protocol.PeerGroupAdvertisement
 * @see         net.jxta.protocol.ModuleImplAdvertisement
 **/
public interface Service extends Module {
    
    /**
     * Service objects are not manipulated directly to protect usage
     * of the service. A Service interface is returned to access the service
     * methods.
     *
     * @return Service public interface of the service
     *
     */
    public Service getInterface();
    
    /**
     * Returns the advertisement for this service.
     *
     * @return Advertisement the advertisement. This is always a 
     * {@code ModuleImplAdvertisement}.
     *
     **/
    public Advertisement getImplAdvertisement();
}