opendaylight/web/topology/src/main/java/org/opendaylight/controller/topology/web/Topology.java

   1
   2 /*
   3  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
   4  *
   5  * This program and the accompanying materials are made available under the
   6  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   7  * and is available at http://www.eclipse.org/legal/epl-v10.html
   8  */
   9
  10 package org.opendaylight.controller.topology.web;
  11
  12 import java.awt.Dimension;
  13 import java.io.FileNotFoundException;
  14 import java.io.IOException;
  15 import java.io.ObjectInputStream;
  16 import java.nio.ByteBuffer;
  17 import java.util.ArrayList;
  18 import java.util.Collection;
  19 import java.util.HashMap;
  20 import java.util.LinkedList;
  21 import java.util.List;
  22 import java.util.Map;
  23 import java.util.Set;
  24
  25 import javax.servlet.http.HttpServletRequest;
  26
  27 import org.opendaylight.controller.configuration.IConfigurationAware;
  28 import org.opendaylight.controller.sal.authorization.Privilege;
  29 import org.opendaylight.controller.sal.core.Bandwidth;
  30 import org.opendaylight.controller.sal.core.Description;
  31 import org.opendaylight.controller.sal.core.Edge;
  32 import org.opendaylight.controller.sal.core.Host;
  33 import org.opendaylight.controller.sal.core.Name;
  34 import org.opendaylight.controller.sal.core.Node;
  35 import org.opendaylight.controller.sal.core.Node.NodeIDType;
  36 import org.opendaylight.controller.sal.core.NodeConnector;
  37 import org.opendaylight.controller.sal.core.Property;
  38 import org.opendaylight.controller.sal.packet.address.EthernetAddress;
  39 import org.opendaylight.controller.sal.utils.GlobalConstants;
  40 import org.opendaylight.controller.sal.utils.IObjectReader;
  41 import org.opendaylight.controller.sal.utils.ObjectReader;
  42 import org.opendaylight.controller.sal.utils.ObjectWriter;
  43 import org.opendaylight.controller.sal.utils.ServiceHelper;
  44 import org.opendaylight.controller.sal.utils.Status;
  45 import org.opendaylight.controller.sal.utils.StatusCode;
  46 import org.opendaylight.controller.switchmanager.ISwitchManager;
  47 import org.opendaylight.controller.switchmanager.Switch;
  48 import org.opendaylight.controller.switchmanager.SwitchConfig;
  49 import org.opendaylight.controller.topologymanager.ITopologyManager;
  50 import org.opendaylight.controller.web.DaylightWebUtil;
  51 import org.springframework.stereotype.Controller;
  52 import org.springframework.web.bind.annotation.PathVariable;
  53 import org.springframework.web.bind.annotation.RequestMapping;
  54 import org.springframework.web.bind.annotation.RequestMethod;
  55 import org.springframework.web.bind.annotation.RequestParam;
  56 import org.springframework.web.bind.annotation.ResponseBody;
  57
  58 import edu.uci.ics.jung.algorithms.layout.CircleLayout;
  59 import edu.uci.ics.jung.graph.Graph;
  60 import edu.uci.ics.jung.graph.SparseMultigraph;
  61
  62 @Controller
  63 @RequestMapping("/")
  64 public class Topology implements IObjectReader, IConfigurationAware {
  65     private static String ROOT = GlobalConstants.STARTUPHOME.toString();
  66     private String topologyWebFileName = null;
  67
  68     protected Map<String, Map<String, Map<String, Object>>> metaCache = new HashMap<String, Map<String, Map<String, Object>>>();
  69     protected Map<String, Map<String, Object>> stagedNodes;
  70     protected Map<String, Map<String, Object>> newNodes;
  71
  72     protected Map<String, Integer> metaNodeHash = new HashMap<String, Integer>();
  73     protected Map<String, Integer> metaHostHash = new HashMap<String, Integer>();
  74     protected Map<String, Integer> metaNodeSingleHash = new HashMap<String, Integer>();
  75     protected Map<String, Integer> metaNodeConfigurationHash = new HashMap<String, Integer>();
  76
  77     public Topology() {
  78         ServiceHelper.registerGlobalService(IConfigurationAware.class, this, null);
  79         topologyWebFileName = ROOT + "topologyCache.sav";
  80         loadConfiguration();
  81     }
  82
  83     /**
  84      * Topology of nodes and hosts in the network in JSON format.
  85      *
  86      * Mainly intended for consumption by the visual topology.
  87      *
  88      * @return - JSON output for visual topology
  89      */
  90     @RequestMapping(value = "/visual.json", method = RequestMethod.GET)
  91     @ResponseBody
  92     public Collection<Map<String, Object>> getLinkData(@RequestParam(required = false) String container, HttpServletRequest request) {
  93         String containerName = (container == null) ? GlobalConstants.DEFAULT.toString() : container;
  94
  95         // Derive the privilege this user has on the current container
  96         String userName = request.getUserPrincipal().getName();
  97         Privilege privilege = DaylightWebUtil.getContainerPrivilege(userName, containerName, this);
  98
  99         if (privilege == Privilege.NONE) {
 100             return null;
 101         }
 102
 103         ITopologyManager topologyManager = (ITopologyManager) ServiceHelper
 104                 .getInstance(ITopologyManager.class, containerName, this);
 105         if (topologyManager == null) {
 106                 return null;
 107         }
 108         ISwitchManager switchManager = (ISwitchManager) ServiceHelper
 109                 .getInstance(ISwitchManager.class, containerName, this);
 110         if (switchManager == null) {
 111                 return null;
 112         }
 113
 114         Map<Node, Set<Edge>> nodeEdges = topologyManager.getNodeEdges();
 115         Map<Node, Set<NodeConnector>> hostEdges = topologyManager
 116                 .getNodesWithNodeConnectorHost();
 117         List<Switch> nodes = switchManager.getNetworkDevices();
 118
 119         List<SwitchConfig> switchConfigurations = new ArrayList<SwitchConfig>();
 120         for(Switch sw : nodes) {
 121                 Node n = sw.getNode();
 122                 SwitchConfig config = switchManager.getSwitchConfig(n.toString());
 123                 switchConfigurations.add(config);
 124         }
 125
 126         // initialize cache if needed
 127         if (!metaCache.containsKey(containerName)) {
 128                 metaCache.put(containerName, new HashMap<String, Map<String, Object>>());
 129                 // initialize hashes
 130                 metaNodeHash.put(containerName, null);
 131                 metaHostHash.put(containerName, null);
 132                 metaNodeSingleHash.put(containerName, null);
 133                 metaNodeConfigurationHash.put(containerName, null);
 134         }
 135
 136         // return cache if topology hasn't changed
 137         if (
 138                 (metaNodeHash.get(containerName) != null && metaHostHash.get(containerName) != null && metaNodeSingleHash.get(containerName) != null && metaNodeConfigurationHash.get(containerName) != null) &&
 139                 metaNodeHash.get(containerName).equals(nodeEdges.hashCode()) && metaHostHash.get(containerName).equals(hostEdges.hashCode()) && metaNodeSingleHash.get(containerName).equals(nodes.hashCode()) && metaNodeConfigurationHash.get(containerName).equals(switchConfigurations.hashCode())
 140         ) {
 141                 return metaCache.get(containerName).values();
 142         }
 143
 144         // cache has changed, we must assign the new values
 145         metaNodeHash.put(containerName, nodeEdges.hashCode());
 146         metaHostHash.put(containerName, hostEdges.hashCode());
 147         metaNodeSingleHash.put(containerName, nodes.hashCode());
 148         metaNodeConfigurationHash.put(containerName, switchConfigurations.hashCode());
 149
 150         stagedNodes = new HashMap<String, Map<String, Object>>();
 151         newNodes = new HashMap<String, Map<String, Object>>();
 152
 153         // nodeEdges addition
 154         addNodes(nodeEdges, topologyManager, switchManager, containerName);
 155
 156         // single nodes addition
 157         addSingleNodes(nodes, switchManager, containerName);
 158
 159         // hostNodes addition
 160         addHostNodes(hostEdges, topologyManager, containerName);
 161
 162         repositionTopology(containerName);
 163
 164         return metaCache.get(containerName).values();
 165     }
 166
 167     /**
 168      * Add regular nodes to main topology
 169      *
 170      * @param nodeEdges - node-edges mapping derived from topology
 171      * @param topology - the topology instance
 172      */
 173     private void addNodes(Map<Node, Set<Edge>> nodeEdges,
 174             ITopologyManager topology, ISwitchManager switchManager, String containerName) {
 175         Bandwidth bandwidth = new Bandwidth(0);
 176         Map<Edge, Set<Property>> properties = topology.getEdges();
 177
 178         for (Map.Entry<Node, Set<Edge>> e : nodeEdges.entrySet()) {
 179             Node n = e.getKey();
 180             String description = getNodeDesc(n, switchManager);
 181
 182             NodeBean node = createNodeBean(description, n);
 183
 184             // skip production node
 185             if (nodeIgnore(n)) {
 186                 continue;
 187             }
 188
 189             List<Map<String, Object>> adjacencies = new LinkedList<Map<String, Object>>();
 190             Set<Edge> links = e.getValue();
 191             for (Edge link : links) {
 192                 if (edgeIgnore(link)) {
 193                     continue;
 194                 }
 195                 for (Property p : properties.get(link)) {
 196                     if (p instanceof Bandwidth) {
 197                         bandwidth = (Bandwidth) p;
 198                         break;
 199                     }
 200                 }
 201                 NodeConnector headNodeConnector = link.getHeadNodeConnector();
 202                 NodeConnector tailNodeConnector = link.getTailNodeConnector();
 203
 204                 String headDescription = this.getNodeConnectorDescription(headNodeConnector, switchManager);
 205                 String tailDescription = this.getNodeConnectorDescription(tailNodeConnector, switchManager);
 206                 String headPortDescription = this.getNodeConnectorPortDescription(headNodeConnector, switchManager);
 207                 String tailPortDescription = this.getNodeConnectorPortDescription(tailNodeConnector, switchManager);
 208                 EdgeBean edge = new EdgeBean(link, bandwidth, headDescription, tailDescription, headPortDescription, tailPortDescription);
 209                 adjacencies.add(edge.out());
 210             }
 211
 212             node.setLinks(adjacencies);
 213             if (metaCache.get(containerName).containsKey(node.id())) {
 214                 // retrieve node from cache
 215                 Map<String, Object> nodeEntry = metaCache.get(containerName).get(node.id());
 216
 217                         Map<String, String> data = (Map<String, String>) nodeEntry.get("data");
 218                         data.put("$desc", description);
 219                         nodeEntry.put("data", data);
 220
 221                 // always update adjacencies
 222                 nodeEntry.put("adjacencies", adjacencies);
 223                 // stage this cached node (with position)
 224                 stagedNodes.put(node.id(), nodeEntry);
 225             } else {
 226                 newNodes.put(node.id(), node.out());
 227             }
 228         }
 229     }
 230
 231     /**
 232      * Check if this node shouldn't appear in the visual topology
 233      *
 234      * @param node
 235      * @return
 236      */
 237     private boolean nodeIgnore(Node node) {
 238         String nodeType = node.getType();
 239
 240         // add other node types to ignore later
 241         if (nodeType.equals(NodeIDType.PRODUCTION)) {
 242             return true;
 243         }
 244
 245         return false;
 246     }
 247
 248     /**
 249      * Check if this edge shouldn't appear in the visual topology
 250      *
 251      * @param edge
 252      * @return
 253      */
 254     private boolean edgeIgnore(Edge edge) {
 255         NodeConnector headNodeConnector = edge.getHeadNodeConnector();
 256         Node headNode = headNodeConnector.getNode();
 257         if (nodeIgnore(headNode)) {
 258             return true;
 259         }
 260
 261         NodeConnector tailNodeConnector = edge.getTailNodeConnector();
 262         Node tailNode = tailNodeConnector.getNode();
 263         if (nodeIgnore(tailNode)) {
 264             return true;
 265         }
 266
 267         return false;
 268     }
 269
 270     protected NodeBean createNodeBean(String description, Node node) {
 271         String name = this.getDescription(description, node);
 272         return  new NodeBean(node.toString(), name, NodeType.NODE);
 273     }
 274
 275     private String getDescription(String description, Node node) {
 276         String name = (description == null ||
 277                 description.trim().isEmpty() ||
 278                 description.equalsIgnoreCase("none"))?
 279                                 node.toString() : description;
 280         return name;
 281     }
 282
 283     private String getNodeConnectorDescription(NodeConnector nodeConnector, ISwitchManager switchManager) {
 284         Node node = nodeConnector.getNode();
 285         String name = this.getDescription(getNodeDesc(node, switchManager), node);
 286         return name;
 287     }
 288
 289     private String getNodeConnectorPortDescription(NodeConnector nodeConnector, ISwitchManager switchManager) {
 290         Name ncName = (Name) switchManager.getNodeConnectorProp(nodeConnector, Name.NamePropName);
 291         String nodeConnectorName = nodeConnector.getNodeConnectorIDString();
 292         if (ncName != null) {
 293             nodeConnectorName = ncName.getValue();
 294         }
 295         return nodeConnectorName;
 296     }
 297
 298     @SuppressWarnings("unchecked")
 299         private void addSingleNodes(List<Switch> nodes, ISwitchManager switchManager, String containerName) {
 300         if (nodes == null) {
 301                 return;
 302         }
 303         for (Switch sw : nodes) {
 304                 Node n = sw.getNode();
 305
 306                 // skip production node
 307                 if (nodeIgnore(n)) {
 308                     continue;
 309                 }
 310
 311                 String description = getNodeDesc(n, switchManager);
 312
 313                 if ((stagedNodes.containsKey(n.toString()) && metaCache.get(containerName).containsKey(n.toString())) || newNodes.containsKey(n.toString())) {
 314                         continue;
 315                 }
 316                 NodeBean node = createNodeBean(description, n);
 317
 318                 // FIXME still doesn't display standalone node when last remaining link is removed
 319                 if (metaCache.get(containerName).containsKey(node.id()) && !stagedNodes.containsKey(node.id())) {
 320                         Map<String, Object> nodeEntry = metaCache.get(containerName).get(node.id());
 321                                 Map<String, String> data = (Map<String, String>) nodeEntry.get("data");
 322                         data.put("$desc", description);
 323                         nodeEntry.put("data", data);
 324                         // clear adjacencies since this is now a single node
 325                         nodeEntry.put("adjacencies", new LinkedList<Map<String, Object>>());
 326                 stagedNodes.put(node.id(), nodeEntry);
 327             } else {
 328                 newNodes.put(node.id(), node.out());
 329             }
 330         }
 331     }
 332
 333     /**
 334      * Add regular hosts to main topology
 335      *
 336      * @param hostEdges - node-nodeconnectors host-specific mapping from topology
 337      * @param topology - topology instance
 338      */
 339     private void addHostNodes(Map<Node, Set<NodeConnector>> hostEdges,
 340             ITopologyManager topology, String containerName) {
 341         for (Map.Entry<Node, Set<NodeConnector>> e : hostEdges.entrySet()) {
 342             for (NodeConnector connector : e.getValue()) {
 343                 Host host = topology.getHostAttachedToNodeConnector(connector);
 344                 EthernetAddress dmac = (EthernetAddress) host.getDataLayerAddress();
 345
 346                 ByteBuffer addressByteBuffer = ByteBuffer.allocate(8);
 347                 addressByteBuffer.putShort((short) 0);
 348                 addressByteBuffer.put(dmac.getValue());
 349                 addressByteBuffer.rewind();
 350
 351                 long hid = addressByteBuffer.getLong();
 352                 String hostId = String.valueOf(hid);
 353
 354                 NodeBean hostBean = new NodeBean(hostId, host.getNetworkAddressAsString(), NodeType.HOST);
 355                 List<Map<String, Object>> adjacencies = new LinkedList<Map<String, Object>>();
 356                 EdgeBean edge = new EdgeBean(connector, hid);
 357                 adjacencies.add(edge.out());
 358                 hostBean.setLinks(adjacencies);
 359
 360                 if (metaCache.get(containerName).containsKey(hostId)) {
 361                         Map<String, Object> hostEntry = metaCache.get(containerName).get(hostId);
 362                         hostEntry.put("adjacencies", adjacencies);
 363                         stagedNodes.put(hostId, hostEntry);
 364                 } else {
 365                         newNodes.put(String.valueOf(hid), hostBean.out());
 366                 }
 367             }
 368         }
 369     }
 370
 371     /**
 372      * Re-position nodes in circular layout
 373      */
 374     private void repositionTopology(String containerName) {
 375         Graph<String, String> graph = new SparseMultigraph<String, String>();
 376
 377         metaCache.get(containerName).clear();
 378         metaCache.get(containerName).putAll(stagedNodes);
 379         metaCache.get(containerName).putAll(newNodes);
 380
 381         for (Map<String, Object> on : metaCache.get(containerName).values()) {
 382             graph.addVertex(on.toString());
 383
 384             List<Map<String, Object>> adjacencies = (List<Map<String, Object>>) on.get("adjacencies");
 385
 386             for (Map<String, Object> adj : adjacencies) {
 387                 graph.addEdge(
 388                         adj.toString(), adj.get("nodeFrom").toString(),
 389                         adj.get("nodeTo").toString()
 390                 );
 391             }
 392         }
 393
 394         CircleLayout<String, String> layout = new CircleLayout<String, String>(graph);
 395         layout.setSize(new Dimension(1200, 365));
 396         for (Map.Entry<String, Map<String, Object>> v : newNodes.entrySet()) {
 397             Double x = layout.transform(v.getKey()).getX();
 398             Double y = layout.transform(v.getKey()).getY();
 399
 400             Map<String, String> nodeData = (HashMap<String, String>) v.getValue().get("data");
 401             nodeData.put("$x", (x - 600) + "");
 402             nodeData.put("$y", (y - 225) + "");
 403
 404             newNodes.get(v.getKey()).put("data", nodeData);
 405         }
 406     }
 407
 408     /**
 409      * Update node position
 410      *
 411      * This method is mainly used by the visual topology
 412      *
 413      * @param nodeId - The node to update
 414      * @return The node object
 415      */
 416     @RequestMapping(value = "/node/{nodeId}", method = RequestMethod.POST)
 417     @ResponseBody
 418     public Map<String, Object> post(@PathVariable String nodeId, @RequestParam(required = true) String x,
 419                 @RequestParam(required = true) String y, @RequestParam(required = false) String container,
 420                 HttpServletRequest request) {
 421         String containerName = (container == null) ? GlobalConstants.DEFAULT.toString() : container;
 422
 423         // Derive the privilege this user has on the current container
 424         String userName = request.getUserPrincipal().getName();
 425         Privilege privilege = DaylightWebUtil.getContainerPrivilege(userName, containerName, this);
 426
 427         if (privilege != Privilege.WRITE) {
 428             return new HashMap<String, Object>(); // silently disregard new node position
 429         }
 430
 431         String id = new String(nodeId);
 432
 433         if (!metaCache.get(containerName).containsKey(id)) {
 434             return null;
 435         }
 436
 437         Map<String, Object> node = metaCache.get(containerName).get(id);
 438         Map<String, String> data = (Map<String, String>) node.get("data");
 439
 440         data.put("$x", x);
 441         data.put("$y", y);
 442
 443         node.put("data", data);
 444
 445         return node;
 446     }
 447
 448     /**
 449      * Node object for visual topology
 450      */
 451     protected class NodeBean {
 452         protected String id;
 453         protected String name;
 454         protected Map<String, String> data;
 455         protected List<Map<String, Object>> links;
 456
 457         public NodeBean() {
 458                 data = new HashMap<String, String>();
 459                 links = new ArrayList<Map<String, Object>>();
 460         }
 461
 462         public NodeBean(String id, String name, String type) {
 463                 this();
 464                 this.id = id;
 465                 this.name = name;
 466                 data.put("$desc", name);
 467                 data.put("$type", type);
 468         }
 469
 470         public void setLinks(List<Map<String, Object>> links) {
 471                 this.links = links;
 472         }
 473
 474         public Map<String, Object> out() {
 475                 Map<String, Object> node = new HashMap<String, Object>();
 476                 node.put("id", this.id);
 477                 node.put("name", this.name);
 478                 node.put("data", this.data);
 479                 node.put("adjacencies", this.links);
 480
 481                 return node;
 482         }
 483
 484         public String name() {
 485                 return this.name;
 486         }
 487
 488         public String id() {
 489                 return this.id;
 490         }
 491     }
 492
 493     /**
 494      * Edge object for visual topology
 495      */
 496     protected class EdgeBean {
 497         protected NodeConnector source;
 498         protected NodeConnector destination;
 499         protected Map<String, String> data;
 500         protected Long hostId;
 501
 502         public EdgeBean() {
 503                 data = new HashMap<String, String>();
 504         }
 505
 506         /**
 507          * EdgeBean object that includes complete node description
 508          *
 509          * @param link
 510          * @param bandwidth
 511          * @param headDescription
 512          * @param tailDescription
 513          */
 514         public EdgeBean(Edge link, Bandwidth bandwidth, String headDescription,
 515                 String tailDescription, String headPortDescription, String tailPortDescription) {
 516             this();
 517             this.source = link.getHeadNodeConnector();
 518             this.destination = link.getTailNodeConnector();
 519
 520             // data
 521             data.put("$bandwidth", bandwidth.toString());
 522             data.put("$color", bandwidthColor(bandwidth));
 523             data.put("$nodeToPort", destination.getID().toString());
 524             data.put("$nodeFromPort", source.getID().toString());
 525             data.put("$descFrom", headDescription);
 526             data.put("$descTo", tailDescription);
 527             data.put("$nodeFromPortName", source.toString());
 528             data.put("$nodeToPortName", destination.toString());
 529             data.put("$nodeFromPortDescription", headPortDescription);
 530             data.put("$nodeToPortDescription", tailPortDescription);
 531         }
 532
 533         public EdgeBean(NodeConnector connector, Long hostId) {
 534             this();
 535             this.source = null;
 536             this.destination = connector;
 537             this.hostId = hostId;
 538
 539             data.put("$bandwidth", "N/A");
 540             data.put("$color", bandwidthColor(new Bandwidth(0)));
 541             data.put("$nodeToPort", connector.getNodeConnectorIDString());
 542             data.put("$nodeFromPort", connector.getNodeConnectorIDString());
 543             data.put("$descTo", "");
 544             data.put("$descFrom", "");
 545             data.put("$nodeToPortName", "");
 546             data.put("$nodeFromPortName", "");
 547         }
 548
 549         public Map<String, Object> out() {
 550                 Map<String, Object> edge = new HashMap<String, Object>();
 551
 552                 edge.put("data", data);
 553                 if (source == null) {
 554                         edge.put("nodeFrom", String.valueOf(this.hostId));
 555                 } else {
 556                         edge.put("nodeFrom", source.getNode().toString());
 557                 }
 558                 edge.put("nodeTo", destination.getNode().toString());
 559
 560
 561                 return edge;
 562         }
 563
 564         private String bandwidthColor(Bandwidth bandwidth) {
 565                 String color = null;
 566                 long bandwidthValue = bandwidth.getValue();
 567
 568                 if (bandwidthValue == 0) {
 569                 color = "#000";
 570             } else if (bandwidthValue < Bandwidth.BW1Kbps) {
 571                 color = "#148AC6";
 572             } else if (bandwidthValue < Bandwidth.BW1Mbps) {
 573                 color = "#2858A0";
 574             } else if (bandwidthValue < Bandwidth.BW1Gbps) {
 575                 color = "#009393";
 576             } else if (bandwidthValue < Bandwidth.BW1Tbps) {
 577                 color = "#C6C014";
 578             } else if (bandwidthValue < Bandwidth.BW1Pbps) {
 579                 color = "#F9F464";
 580             }
 581
 582                 return color;
 583         }
 584     }
 585
 586     protected class NodeType {
 587         public static final String NODE = "swtch";
 588         public static final String HOST = "host";
 589     }
 590
 591     @SuppressWarnings("unchecked")
 592         private void loadConfiguration() {
 593         ObjectReader objReader = new ObjectReader();
 594         metaCache = (Map<String, Map<String, Map<String, Object>>>) objReader.read(this, topologyWebFileName);
 595         if (metaCache == null) {
 596             metaCache = new HashMap<String, Map<String, Map<String, Object>>>();
 597         }
 598     }
 599
 600     @Override
 601     public Status saveConfiguration() {
 602         ObjectWriter objWriter = new ObjectWriter();
 603         objWriter.write(metaCache, topologyWebFileName);
 604         return new Status(StatusCode.SUCCESS, null);
 605     }
 606
 607     @Override
 608     public Object readObject(ObjectInputStream ois)
 609             throws FileNotFoundException, IOException, ClassNotFoundException {
 610         // Perform the class deserialization locally, from inside the package where the class is defined
 611         return ois.readObject();
 612     }
 613
 614     private String getNodeDesc(Node node, ISwitchManager switchManager) {
 615         Description desc = (Description) switchManager.getNodeProp(node, Description.propertyName);
 616         return (desc == null) ? "" : desc.getValue();
 617     }
 618
 619 }