genericpeergroup.java

jxta平台的开发包

                return;
            }
            
            if (!stopWhenUnreferenced) {
                return;
            }
        }
        
        if (LOG.isEnabledFor(Level.INFO)) {
            LOG.info("[" + getPeerGroupID() + "] STOPPING UNREFERENCED GROUP" );
        }
        
        stopApp();
        
        masterRefCount = Integer.MIN_VALUE;
    }
    
    /*
     * Implement the Service API so that we can make groups services when we
     * decide to.
     */
    
    /**
     *  {@inheritDoc}
     **/
    public Service getInterface() {
        synchronized (this) {
            ++masterRefCount;
            
            if( masterRefCount < 1 ) {
                throw new IllegalStateException( "Group has been shutdown. getInterface() is not available");
            }
            
            if (LOG.isEnabledFor(Level.INFO)) {
                Throwable trace = new Throwable( "Stack Trace" );
                StackTraceElement elements[] = trace.getStackTrace();
                LOG.info("[" + getPeerGroupID() + "] GROUP REF COUNT INCREMENTED TO: " + masterRefCount +
                " by\n\t" + elements[2] );
            }
            
            if (initComplete) {
                // If init is complete the group can become sensitive to
                // its ref count reaching zero. Before there could be
                // transient references before there is a chance to give
                // a permanent reference to the invoker of newGroup.
                stopWhenUnreferenced = true;
            }
        }
        
        return new RefCountPeerGroupInterface(this);
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerGroup getWeakInterface() {
        return new PeerGroupInterface(this);
    }
    
    /**
     *  {@inheritDoc}
     **/
    public Advertisement getImplAdvertisement() {
        return (Advertisement) implAdvertisement.clone();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public void publishGroup(String name, String description) throws IOException {
        
        if (published) {
            return;
        }
        
        peerGroupAdvertisement.setName(name);
        peerGroupAdvertisement.setDescription(description);
        
        if (parentGroup == null) {
            return;
        }
        
        DiscoveryService parentDiscovery = parentGroup.getDiscoveryService();
        
        if( null == parentDiscovery ) {
            return;
        }
        
        parentDiscovery.publish(peerGroupAdvertisement, DEFAULT_LIFETIME, DEFAULT_EXPIRATION);
        
        published = true;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerGroup newGroup(Advertisement pgAdv) throws PeerGroupException {
        
        PeerGroupAdvertisement adv = (PeerGroupAdvertisement) pgAdv;
        
        PeerGroupID gid = adv.getPeerGroupID();
        
        if ((gid == null) || ID.nullID.equals(gid)) {
            throw new IllegalArgumentException("Advertisement did not contain a peer group ID");
        }
        
        PeerGroup theNewGroup = globalRegistry.lookupInstance(gid);
        
        if (theNewGroup != null) {
            return theNewGroup;
        }
        
        // We do not know if the grp adv had been previously published or not...  Since it may contain information essential to
        // the configuration of services, we need to make sure it is published localy, rather than letting the group publish
        // itself after the fact.
        
        // FIXME [e-mail] 20040713 : The downside is that we're publishing the adv even before making sure that this group
        // can really be instantiated. We're basically using the cm as a means to pass parameters to the module because it is a
        // group. We have the same parameter issue with the config adv. Eventually we need to find a clean way of passing
        // parameters specific to a certain types of module.
        
        try {
            discovery.publish(adv, DEFAULT_LIFETIME, DEFAULT_EXPIRATION);
        } catch (Exception any) {
            if (LOG.isEnabledFor(Level.WARN)) {
                LOG.warn("Could not publish the group advertisement: ", any);
            }
        }
        
        theNewGroup = (PeerGroup) loadModule( adv.getPeerGroupID(), adv.getModuleSpecID(), Here, false);
        
        if (theNewGroup == null) {
            throw new PeerGroupException( "Could not find group implementation with " + adv.getModuleSpecID() );
        }
        
        return (PeerGroup) theNewGroup.getInterface();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerGroup newGroup(PeerGroupID gid, Advertisement impl,
    String name, String description)
    throws PeerGroupException {
        PeerGroup theNewGroup = null;
        
        if (null != gid) {
            theNewGroup = globalRegistry.lookupInstance(gid);
        }
        
        if (theNewGroup != null) {
            return theNewGroup;
        }
        
        try {
            theNewGroup = (PeerGroup) loadModule(gid, (ModuleImplAdvertisement) impl, false);
        } catch (Throwable any) {
            if (LOG.isEnabledFor(Level.ERROR)) {
                LOG.error( "Could not load group implementation", any );
            }
            
            throw new PeerGroupException( "Could not load group implementation", any );
        }
        
        try {
            // The group adv definitely needs to be published.
            theNewGroup.publishGroup(name, description);
        } catch (Exception any) {
            if (LOG.isEnabledFor(Level.WARN)) {
                LOG.warn( "Could not publish group or implementation:", any );
            }
        }
        
        return (PeerGroup) theNewGroup.getInterface();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerGroup newGroup(PeerGroupID gid) throws PeerGroupException {
        
        if ((gid == null) || ID.nullID.equals(gid)) {
            throw new IllegalArgumentException("Invalid peer group ID");
        }
        
        PeerGroup result = globalRegistry.lookupInstance(gid);
        
        if (result != null) {
            return result;
        }
        
        PeerGroupAdvertisement adv;
        
        try {
            adv = (PeerGroupAdvertisement)
            discoverOne(DiscoveryService.GROUP, "GID", gid.toString(), 120, PeerGroupAdvertisement.class );
        } catch ( Throwable any ) {
            throw new PeerGroupException( "Failed finding group advertisement for " + gid, any );
        }
        
        if (adv == null) {
            throw new PeerGroupException("Could not find group advertisement for group " + gid );
        }
        
        return newGroup( adv );
    }
    
    /**
     *  {@inheritDoc}
     **/
    public JxtaLoader getLoader() {
        return loader;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public String getPeerName() {
        // before init we must fail.
        if(null == peerAdvertisement) {
            throw new IllegalStateException( "PeerGroup not sufficiently initialized" );
        }

        return peerAdvertisement.getName();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public String getPeerGroupName() {
        // before init we must fail.
        if(null == peerGroupAdvertisement) {
            throw new IllegalStateException( "PeerGroup not sufficiently initialized" );
        }

        return peerGroupAdvertisement.getName();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerGroupID getPeerGroupID() {
        // before init we must fail.
        if(null == peerGroupAdvertisement) {
            throw new IllegalStateException( "PeerGroup not sufficiently initialized" );
        }

        return peerGroupAdvertisement.getPeerGroupID();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerID getPeerID() {
        // before init we must fail.
        if(null == peerAdvertisement) {
            throw new IllegalStateException( "PeerGroup not sufficiently initialized" );
        }

        return peerAdvertisement.getPeerID();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerAdvertisement getPeerAdvertisement() {
        return peerAdvertisement;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public PeerGroupAdvertisement getPeerGroupAdvertisement() {
        return peerGroupAdvertisement;
    }
    
    /**
     *  {@inheritDoc}
     **/
    public boolean isRendezvous() {
        if (rendezvous == null) {
            if (LOG.isEnabledFor(Level.DEBUG)) {
                LOG.debug("Rendezvous service null");
            }
        }
        return (rendezvous != null) && rendezvous.isRendezVous();
    }
    
    /*
     * shortcuts to the well-known services, in order to avoid calls to lookup.
     */
    
    /**
     * {@inheritDoc}
     **/
    public EndpointService getEndpointService() {
        if (endpoint == null) {
            return null;
        }
        return (EndpointService) endpoint.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public ResolverService getResolverService() {
        if (resolver == null) {
            return null;
        }
        return (ResolverService) resolver.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public DiscoveryService getDiscoveryService() {
        if (discovery == null) {
            return null;
        }
        return (DiscoveryService) discovery.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public PeerInfoService getPeerInfoService() {
        if (peerinfo == null) {
            return null;
        }
        return (PeerInfoService) peerinfo.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public MembershipService getMembershipService() {
        if (membership == null) {
            return null;
        }
        return (MembershipService) membership.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public PipeService getPipeService() {
        if (pipe == null) {
            return null;
        }
        return (PipeService) pipe.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public RendezVousService getRendezVousService() {
        if (rendezvous == null) {
            return null;
        }
        return (RendezVousService) rendezvous.getInterface();
    }
    
    /**
     * {@inheritDoc}
     **/
    public AccessService getAccessService() {
        if (access == null) {
            return null;
        }
        
        return (AccessService) access.getInterface();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public abstract ModuleImplAdvertisement getAllPurposePeerGroupImplAdvertisement();
    
    
    /**
     *  {@inheritDoc}
     *
     * <p/>We do not want to count on the invoker to properly unreference
     * the group object that we return; this call is often used in a
     * loop and it is silly to increment and decrement ref-counts for
     * references that are sure to live shorter than the referee.
     * On the other hand it is dangerous for us to share our reference
     * object to the parent group. That's where weak interface objects
     * come in handy. We can safely make one and give it away.
     */
    public PeerGroup getParentGroup() {
        if (parentGroup == null) {
            return null;
        }
        return parentGroup.getWeakInterface();
    }
    
    /**
     *  {@inheritDoc}
     **/
    public URI getStoreHome() {
        return jxtaHome;
    }
}