piperesolver.java

jxme的一些相关程序,主要是手机上程序开发以及手机和计算机通信的一些程序资料,程序编译需要Ant支持

            doc.appendChild(e);
            e = doc.createElement(PeerIdTag, peer);
            doc.appendChild(e);
            e = doc.createElement(CachedTag, "false");
            doc.appendChild(e);
            StringWriter dumped = new StringWriter();
            doc.sendToWriter(dumped);
            
            ResolverQuery query = new ResolverQuery(PipeResolverName,
            null,
            localPeerId,
            dumped.toString(), qid++);
            
            resolver.sendQuery(peer, query);
            
        } catch (Exception e) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("sendVerify failed with " + e);
            return;
        }
    }
    
    
    /**
     *   processResponse deals with pipe resolver responses
     *
     * @param  response    ResolverResponse containing the payload
     * @since 1.0
     */
    
    public void processResponse(ResolverResponseMsg response) {
        
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processResponse got a response");
        Enumeration enum = null;
        String peer = null;
        MimeMediaType mediaType = null;
        String ipId = null;
        String type = null;
        String peerAdv = null;
        
        try {
            mediaType = new MimeMediaType("text/xml");
        } catch (RuntimeException e) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processResponse: cannot get MimeMediaType " + e);
            return;
        }
        
        ByteArrayInputStream ip =
        new ByteArrayInputStream(response.getResponse().getBytes());
        
        StructuredDocument doc = null;
        try {
            
            doc = StructuredDocumentFactory.newStructuredDocument(mediaType, ip);
            
        } catch (Exception e) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processResponse: malformed response - discard");
            return;
        }
        // XXX: we are doing no document sanity check here.
        // Maybe should we be more careful.
        // to be fixed. [e-mail]
        
        enum = doc.getChildren();
        Vector tmp = new Vector();
        boolean found = true;
        
        while (enum.hasMoreElements()) {
            TextElement elem = (TextElement) enum.nextElement();
            if (elem.getName().equals(PeerIdTag)) {
                tmp.addElement(elem.getValue());
                continue;
            }
            if (elem.getName().equals(PipeIdTag)) {
                ipId = (String) elem.getValue();
                continue;
            }
            if (elem.getName().equals(TypeTag)) {
                type = (String) elem.getValue();
                continue;
            }
            if (elem.getName().equals(FoundTag)) {
                found = ((String) elem.getValue()).equals("true");
                continue;
            }
            // let's check whether the responder sent us a adv
            if (elem.getName().equals(PeerAdvTag)) {
                peerAdv = (String) elem.getValue();
                saveAdv(peerAdv);
                continue;
            }
        }
        
        if ((ipId == null) || (tmp.size() == 0)) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processResponse: malformed response - discard.");
            // Malformed response. Just discard.
            return;
        }
        
        if (type == null) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processResponse: no type - using UnicastType as default");
            type = PipeService.UnicastType;
        }
        
        enum = tmp.elements();
        if (enum == null) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processResponse: empty response");
            return;
        }
        
        while (enum.hasMoreElements()) {
            peer = (String) enum.nextElement();
            if (!found) {
                // We have received a NACK.
                String cachedPeer = findLocal(ipId);
                if ((cachedPeer != null) && cachedPeer.equals(peer)) {
                    // Remove that entry.
                    forgetCached(ipId);
                    return;
                    // May be we should forward the nacks ?
                }
            } else {
                // put the answer into the cache.
                registerCached(ipId, peer);
                
                // call any listener for ipid
                if ( listeners.containsKey(ipId) ) {
                    Event newevent = new Event(this,
                    peer,
                    ipId,
                    type,
                    response.getQueryId() );
                    Listener pl = (Listener) listeners.get(ipId);
                    pl.pipeResolverEvent(newevent);
                }
            }
        }
        // FIXME: [[e-mail] 20010914] Why do we respond with the
        // last peer from the above loop only? Why are there several peers
        // though? Should we be responding when we got a Nack?
    }
    
    
    /**
     * Process the Query, and genrate response
     *
     * @param  query                      Description of Parameter
     * @return                            ResolverResponseMsg "Response"
     * @exception  NoResponseException    Description of Exception
     * @exception  DiscardQueryException  Description of Exception
     * @exception  IOException            Description of Exception
     * @exception  ResendQueryException   Description of Exception
     * @since 1.0
     */
    public ResolverResponseMsg processQuery(ResolverQueryMsg query)
    throws NoResponseException,
    DiscardQueryException,
    IOException,
    ResendQueryException {
        
        if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery starts");
        MimeMediaType mediaType = null;
        mediaType = new MimeMediaType("text/xml");
        
        ByteArrayInputStream ip =
        new ByteArrayInputStream(query.getQuery().getBytes());
        
        StructuredTextDocument doc = null;
        try {
            doc = (StructuredTextDocument)
            StructuredDocumentFactory.newStructuredDocument( mediaType, ip );
        } catch (Exception e) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: malformed request ", e);
            throw new IOException("processQuery: malformed request ");
        }
        // XXX: we are doing no document sanity check here.
        // Maybe should we be more careful. to be fixed. [e-mail]
        
        String pId = null;
        boolean cached = true;
        String destPeer = null;
        String type = null;
        
        Enumeration enum = doc.getChildren();
        
        while (enum.hasMoreElements()) {
            TextElement elem = (TextElement) enum.nextElement();
            if (elem.getName().equals(PipeIdTag)) {
                pId = (String) elem.getValue();
                continue;
            }
            if (elem.getName().equals(PeerIdTag)) {
                destPeer = (String) elem.getValue();
                continue;
            }
            if (elem.getName().equals(TypeTag)) {
                type = (String) elem.getValue();
                continue;
            }
            if (elem.getName().equals(CachedTag)) {
                cached = ((String) elem.getValue()).equals("true");
                continue;
            }
        }
        if (pId == null) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: malformed request, no PipeId.");
            throw new IOException();
        }
        
        if (type == null) {
            // If type is null, discard the request.
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: type is null, discarded.");
            throw new DiscardQueryException("processQuery: type is null, discarded.");
        }
        
        if ((destPeer != null) && !destPeer.equals(localPeerId)) {
            // This request wasn't for this peer.
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: request not for this peer, discarded.");
            throw new DiscardQueryException("processQuery: request not for this peer, discarded.");
        }
        
        int queryId = query.getQueryId();
        String peer = null;
        
        // XXX: Only one query at the time...
        // Maybe that should be changed later. [e-mail]
        
        if (!cached) {
            // The source of the query has requeried not to receive
            // cached information.
            if (pipes.get(pId) != null) {
                peer = localPeerId;
            } else {
                peer = null;
            }
        } else {
            // We can look into our cache.
            peer = findLocal(pId);
        }
        
        if ((peer == null) && (destPeer == null)) {
            // This request was sent to everyone.
            // If this peer is a rendezvous, allow the ResolverService to repropagate
            // the query. If this peer is not a rendezvous, just discard the query.
            if (myGroup.isRendezvous()) {
                throw new NoResponseException();
            } else {
                if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: message discarded.");
                throw new DiscardQueryException("processQuery: message discarded.");
            }
        }
        
        try {
            // Build the answer
            doc = (StructuredTextDocument)
            StructuredDocumentFactory.newStructuredDocument(
            new MimeMediaType("text/xml"), "jxta:PipeResolver");
            
            Element e = null;
            e = doc.createElement(MsgTypeTag, AnswerMsgType);
            doc.appendChild(e);
            e = doc.createElement(PipeIdTag, pId);
            doc.appendChild(e);
            e = doc.createElement(TypeTag, type);
            doc.appendChild(e);
            if (peer == null) {
                // We are sending a NACK
                e = doc.createElement(PeerIdTag, localPeerId);
                doc.appendChild(e);
                e = doc.createElement(FoundTag, "false");
                doc.appendChild(e);
            } else {
                e = doc.createElement(PeerIdTag, peer);
                doc.appendChild(e);
                // this saves the remote peer a big step in resolving pid to endpoint
                String advStr = advString(peer);
                if (advStr != null) {
                    e = doc.createElement(PeerAdvTag, advStr);
                    doc.appendChild(e);
                }
            }
            
            StringWriter dumped = new StringWriter();
            doc.sendToWriter(dumped);
            
            ResolverResponse res = new ResolverResponse(PipeResolverName,
            null,
            queryId,
            dumped.toString());
            
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: sending answer.");
            return res;
        } catch (Exception ee) {
            if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("processQuery: error while processing query:", ee);
            throw new IOException( ee.toString() );
        }
    }
    
    
    /**
     *Description of the Method
     *
     * @param  timer  Description of Parameter
     * @since 1.0
     */
    public void signal(JxtaTimer timer) {
        
        refreshCachedPipes();
    }
    
    
    
    /**
     *Description of the Method
     *
     * @param  entry  Description of Parameter
     * @since 1.0
     */
    private void resetLease(PipeEntry entry) {
        
        if (entry == null) {
            return;
        }
        
        long currentTime = System.currentTimeMillis();
        entry.lease = currentTime + DefaultPipeLease;
    }
    
    
    /**
     *Description of the Method
     *
     * @since 1.0
     */
    private synchronized void refreshCachedPipes() {
        
        long currentTime = System.currentTimeMillis();
        Enumeration enum = cachedPipes.keys();
        if ((enum == null) || (!enum.hasMoreElements())) {
            return;
        }
        PipeEntry entry = null;
        String pipe = null;
        while (enum.hasMoreElements()) {
            try {
                pipe = (String) enum.nextElement();
                entry = (PipeEntry) cachedPipes.get(pipe);
                if (entry == null) {
                    if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("refreshCachedPipe: empty entry for pipe " + pipe);
                    continue;
                }
                if (entry.lease < currentTime) {
                    // Remove that entry.
                    cachedPipes.remove(pipe);
                    continue;
                }
            } catch (Exception e) {
                if (LOG.isEnabledFor(Priority.DEBUG)) LOG.debug("refreshCachedPipe: " + e);
                break;
            }
        }