netpeergroupfactory.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

     *  @param storeHome The optional location that the World Peer Group, the
     *  Net Peer Group and its' services should use for storing persistent and
     *  transient information. May be {@code null} if the World Peer Group is 
     *  not provided a persistent store (though this not currently supported).
     *  @param id The PeerGroupID which will be used for the new Net Peer Group
     *  instance.
     *  @param name The name which will be used for the new Net Peer Group
     *  instance.
     *  @param desc The description which will be used for the new Net Peer Group
     *  instance. You can construct an {@code XMLDocument} from a {@code String}
     *  via : 
     *  <p/><pre>
     *  XMLDocument asDoc = StructuredDocumentFactory.newStructuredDocument( MimeMediaType.XMLUTF8, "desc", asString );
     *  </pre>
     *  @throws PeerGroupException Thrown for problems constructing the Net Peer
     *  Group.
     **/
    public NetPeerGroupFactory( ConfigParams config, URI storeHome, ID id, String name, XMLElement desc ) throws PeerGroupException {
        WorldPeerGroupFactory world = new WorldPeerGroupFactory( config, storeHome );
        PeerGroup worldGroup = world.getInterface();
        
        try {
            net = newNetPeerGroup( worldGroup, id, name, desc, null );
        } finally {
            worldGroup.unref();
        }
    }
    
    /**
     *  Constructs a Net Peer Group instance using the specified parent peer 
     *  group (normally the World Peer Group). This is the preferred constructor 
     *  for constructing a private Net Peer Group.
     *
     *  @param parentGroup The Peer Group which will be the parent of the
     *  newly created net peer group. This should normally be the World Peer
     *  Group.
     *  @param id The PeerGroupID which will be used for the new Net Peer Group
     *  instance.
     *  @param name The name which will be used for the new Net Peer Group
     *  instance.
     *  @param desc The description which will be used for the new Net Peer Group
     *  instance. You can construct an {@code XMLDocument} from a {@code String}
     *  via : 
     *  <p/><pre>
     *  XMLDocument asDoc = StructuredDocumentFactory.newStructuredDocument( MimeMediaType.XMLUTF8, "desc", asString );
     *  </pre>
     *  @throws PeerGroupException Thrown for problems constructing the Net Peer
     *  Group.
     **/
    public NetPeerGroupFactory( PeerGroup parentGroup, ID id, String name, XMLElement desc ) throws PeerGroupException {
        net = newNetPeerGroup( parentGroup, id, name, desc, null );
    }
    
    /**
     *  Constructs a Net Peer Group instance using the specified parent peer 
     *  group (normally the World Peer Group). This is the preferred constructor 
     *  for constructing a private Net Peer Group with a specific implementation.
     *
     *  @param parentGroup The Peer Group which will be the parent of the
     *  newly created net peer group. This should normally be the World Peer
     *  Group.
     *  @param id The PeerGroupID which will be used for the new Net Peer Group
     *  instance.
     *  @param name The name which will be used for the new Net Peer Group
     *  instance.
     *  @param desc The description which will be used for the new Net Peer Group
     *  instance. You can construct an {@code XMLDocument} from a {@code String}
     *  via : 
     *  <p/><pre>
     *  XMLDocument asDoc = StructuredDocumentFactory.newStructuredDocument( MimeMediaType.XMLUTF8, "desc", asString );
     *  </pre>
     *  @param moduleImplAdv The Module Impl Advertisement for the new Net Peer 
     *  Group instance.
     *  @throws PeerGroupException Thrown for problems constructing the Net Peer
     *  Group.
     **/
    public NetPeerGroupFactory( PeerGroup parentGroup, ID id, String name, XMLElement desc, ModuleImplAdvertisement moduleImplAdv ) throws PeerGroupException {
        net = newNetPeerGroup( parentGroup, id, name, desc, moduleImplAdv );
    }
    
    /**
     *  Returns a strong (reference counted) interface object for the Net Peer
     *  Group instance. This reference should be explicitly unreferenced when it
     *  is no longer needed.
     *
     *  @see PeerGroup#unref()
     *
     *  @return A strong (reference counted) interface object for the Net Peer Group.
     **/
    public PeerGroup getInterface() {
        return (PeerGroup) net.getInterface();
    }
    
    /**
     *  Returns a weak (non-reference counted) interface object for the Net Peer Group.
     *
     *  @see PeerGroup#getWeakInterface()
     *
     *  @return A weak (non-reference counted) interface object for the Net Peer Group.
     **/
    public PeerGroup getWeakInterface() {
        return net.getWeakInterface();
    }
    
    /**
     *  Construct the new Net Peer Group instance.
     *
     *  @param parentGroup The parent group of the newly created net peer group.
     *  @param id The name to use for the newly created Net Peer Group.
     *  @param name The name to use for the newly created Net Peer Group.
     *  @param desc The description to use for the newly created Net Peer Group.
     *  @param implAdv The Module Impl Advertisement for the new Net Peer 
     *  Group instance or {@code null} to use the advertisement returned by
     *  {@ link PeerGroup.getAllPurposePeerGroupImplAdvertisement()}.
     *  @throws PeerGroupException Thrown for problems constructing the Net Peer
     *  Group.
     **/
    private PeerGroup newNetPeerGroup( PeerGroup parentGroup, ID id, String name, XMLElement desc, ModuleImplAdvertisement implAdv ) throws PeerGroupException {
        synchronized( PeerGroup.globalRegistry ) {
            PeerGroup result = PeerGroup.globalRegistry.lookupInstance( (PeerGroupID) id );
            
            if( null != result ) {
                throw new PeerGroupException( "Only a single instance of the World Peer Group may be instantiated at a single time." );
            }
            
            if (LOG.isEnabledFor(Level.INFO)) {
                LOG.info( "Instantiating net peer group : " + id +
                        "\n\tParent : " + parentGroup +
                        "\n\tID : " + id +
                        "\n\tName : " + name +
                        "\n\timpl : " + implAdv );
            }
            
            try {
                if( null == implAdv ) {
                    // Use the default Peer Group Impl Advertisement
                    implAdv = parentGroup.getAllPurposePeerGroupImplAdvertisement();
                }
                
                // Build the group
                
                result = (PeerGroup) parentGroup.loadModule( id, implAdv );
                
                // Set the name and description
                // FIXME 20060217 bondolo How sad, we can't use our XML description.
                result.publishGroup( name, desc.getTextValue() );
                
                return result;
            } catch(PeerGroupException failed) {
                if (LOG.isEnabledFor(Level.FATAL)) {
                    LOG.fatal("newNetPeerGroup failed", failed);
                }
                // rethrow
                throw failed;
            } catch(RuntimeException e) {
                if (LOG.isEnabledFor(Level.FATAL)) {
                    LOG.fatal("newNetPeerGroup failed", e);
                }
                // rethrow
                throw e;
            } catch(Exception e) {
                // should be all other checked exceptions
                if (LOG.isEnabledFor(Level.FATAL)) {
                    LOG.fatal("newNetPeerGroup failed", e);
                }
                // Simplify exception scheme for caller: any sort of problem wrapped
                // in a PeerGroupException.
                throw new PeerGroupException("newNetPeerGroup failed", e);
            }
        }
    }
    
    /**
     *  Holds the construction tunables for the Net Peer Group. This consists of
     *  the peer group id, the peer group name and the peer group description.
     **/
    static class NetGroupTunables {
        
        final ID id;
        final String name;
        final XMLElement desc;
        
        /**
         *  Constructor for loading the default Net Peer Group construction
         *  tunables.
         **/
        NetGroupTunables( ) {
            id = PeerGroupID.defaultNetPeerGroupID;
            name = "NetPeerGroup";
            desc = (XMLElement) StructuredDocumentFactory.newStructuredDocument( MimeMediaType.XMLUTF8, "desc", "default Net Peer Group");
        }
        
        /**
         *  Constructor for loading the default Net Peer Group construction
         *  tunables.
         **/
        NetGroupTunables( ID pgid, String pgname, XMLElement pgdesc ) {
            id = pgid;
            name = pgname;
            desc = pgdesc;
        }
        
        /**
         *  Constructor for loading the Net Peer Group construction
         *  tunables from the provided resource bundle.
         *
         *  @param rsrcs The resource bundle from which resources will be loaded.
         **/
        NetGroupTunables( ResourceBundle rsrcs, NetGroupTunables defaults ) {
            ID idTmp;
            String nameTmp;
            XMLElement descTmp;
            
            try {
                String idTmpStr = rsrcs.getString("NetPeerGroupID").trim();
                if( idTmpStr.startsWith(ID.URNNamespace + ":") ) {
                    idTmpStr = idTmpStr.substring( 5 );
                }
                idTmp = IDFactory.fromURI(new URI(ID.URIEncodingName + ":" + ID.URNNamespace + ":" + idTmpStr));
                nameTmp = rsrcs.getString("NetPeerGroupName").trim();
                descTmp = (XMLElement) StructuredDocumentFactory.newStructuredDocument( MimeMediaType.XMLUTF8, "desc", rsrcs.getString("NetPeerGroupDesc").trim() );
            } catch( Exception failed ) {
                if( null != defaults ) {
                    if( LOG.isEnabledFor( Level.DEBUG ) ) {
                        LOG.debug( "NetPeerGroup tunables not defined or could not be loaded. Using defaults.", failed );
                    }
                    
                    idTmp = defaults.id;
                    nameTmp = defaults.name;
                    descTmp = defaults.desc;
                } else {
                    if( LOG.isEnabledFor( Level.ERROR ) ) {
                        LOG.error( "NetPeerGroup tunables not defined or could not be loaded.", failed );
                    }
                    
                    throw new IllegalStateException( "NetPeerGroup tunables not defined or could not be loaded." );
                }
            }
            
            id = idTmp;
            name = nameTmp;
            desc = descTmp;
        }
    }
}