org.simantics.g3d.vtk/src/org/simantics/g3d/vtk/common/AbstractVTKNodeMap.java

   1 /*******************************************************************************
   2  * Copyright (c) 2012, 2013 Association for Decentralized Information Management in
   3  * Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.g3d.vtk.common;
  13
  14 import java.lang.reflect.InvocationTargetException;
  15 import java.util.ArrayDeque;
  16 import java.util.ArrayList;
  17 import java.util.Collection;
  18 import java.util.Collections;
  19 import java.util.Deque;
  20 import java.util.HashMap;
  21 import java.util.HashSet;
  22 import java.util.List;
  23 import java.util.Map;
  24 import java.util.Set;
  25 import java.util.Stack;
  26
  27 import org.eclipse.ui.PlatformUI;
  28 import org.eclipse.ui.progress.IProgressService;
  29 import org.simantics.db.ReadGraph;
  30 import org.simantics.db.Session;
  31 import org.simantics.db.UndoContext;
  32 import org.simantics.db.WriteGraph;
  33 import org.simantics.db.common.request.ReadRequest;
  34 import org.simantics.db.common.request.WriteRequest;
  35 import org.simantics.db.exception.DatabaseException;
  36 import org.simantics.db.layer0.util.Layer0Utils;
  37 import org.simantics.db.service.UndoRedoSupport;
  38 import org.simantics.g3d.ontology.G3D;
  39 import org.simantics.g3d.scenegraph.RenderListener;
  40 import org.simantics.g3d.scenegraph.base.INode;
  41 import org.simantics.g3d.scenegraph.base.NodeListener;
  42 import org.simantics.g3d.scenegraph.base.ParentNode;
  43 import org.simantics.objmap.exceptions.MappingException;
  44 import org.simantics.objmap.graph.IMapping;
  45 import org.simantics.objmap.graph.IMappingListener;
  46 import org.simantics.utils.datastructures.MapList;
  47 import org.simantics.utils.datastructures.MapSet;
  48 import org.simantics.utils.datastructures.Pair;
  49 import org.simantics.utils.ui.ExceptionUtils;
  50 import org.slf4j.Logger;
  51 import org.slf4j.LoggerFactory;
  52
  53 import vtk.vtkProp;
  54
  55 public abstract class AbstractVTKNodeMap<DBObject,E extends INode> implements VTKNodeMap<DBObject,E>, IMappingListener, RenderListener, NodeListener, UndoRedoSupport.ChangeListener{
  56
  57         private static final boolean DEBUG = true;
  58
  59         private static final Logger LOGGER = LoggerFactory.getLogger(AbstractVTKNodeMap.class);
  60
  61         protected Session session;
  62         protected IMapping<DBObject, INode> mapping;
  63         protected VtkView view;
  64
  65         private MapList<E, vtkProp> nodeToActor = new MapList<E, vtkProp>();
  66         private Map<vtkProp,E> actorToNode = new HashMap<vtkProp, E>();
  67
  68         protected ParentNode<E> rootNode;
  69
  70         protected UndoRedoSupport undoRedoSupport;
  71         protected int undoOpCount = 0;
  72         protected int redoOpCount = 0;
  73         protected boolean runUndo = false;
  74         protected boolean runRedo = false;
  75         public AbstractVTKNodeMap(Session session, IMapping<DBObject,INode> mapping, VtkView view, ParentNode<E> rootNode) {
  76                 this.session = session;
  77                 this.mapping = mapping;
  78                 this.view = view;
  79                 this.rootNode = rootNode;
  80                 view.addListener(this);
  81                 mapping.addMappingListener(this);
  82                 rootNode.addListener(this);
  83
  84                 undoRedoSupport = session.getService(UndoRedoSupport.class);
  85                 undoRedoSupport.subscribe(this);
  86                 try {
  87                         UndoContext undoContext = undoRedoSupport.getUndoContext(session);
  88                         undoOpCount = undoContext.getAll().size();
  89                         redoOpCount = undoContext.getRedoList().size();
  90                 } catch(DatabaseException e) {
  91                         e.printStackTrace();
  92                 }
  93         }
  94
  95         protected abstract void addActor(E node);
  96         protected abstract void removeActor(E node);
  97         protected abstract void updateActor(E node,Set<String> ids);
  98
  99         public void repaint() {
 100                 view.refresh();
 101         }
 102
 103         public void populate() {
 104                 for (E node : rootNode.getNodes()) {
 105                         receiveAdd(node, node.getParentRel(),true);
 106                 }
 107                 repaint();
 108         }
 109
 110         @Override
 111         public E getNode(vtkProp prop) {
 112                 return actorToNode.get(prop);
 113         }
 114
 115         @SuppressWarnings("unchecked")
 116         @Override
 117         public Collection<vtkProp> getRenderObjects(INode node) {
 118                 return nodeToActor.getValues((E) node);
 119         }
 120
 121         protected <T extends vtkProp> void map(E node, Collection<T> props) {
 122             for (vtkProp p : props) {
 123                 nodeToActor.add(node, p);
 124                 actorToNode.put(p, node);
 125             }
 126         }
 127
 128         protected void removeMap(E node) {
 129             Collection<vtkProp> coll = nodeToActor.getValuesUnsafe(node);
 130             if (coll.size() > 0) {
 131                 view.lock();
 132             for (vtkProp p : coll) {
 133                 actorToNode.remove(p);
 134                 if (p.GetVTKId() != 0) {
 135                     view.getRenderer().RemoveActor(p);
 136                     p.Delete();
 137                 }
 138             }
 139             view.unlock();
 140             }
 141             nodeToActor.remove(node);
 142         }
 143
 144         @Override
 145         public ParentNode<E> getRootNode() {
 146                 return (ParentNode<E>)rootNode;
 147         }
 148
 149
 150
 151         @Override
 152         public boolean isChangeTracking() {
 153                 return changeTracking;
 154         }
 155
 156         @Override
 157         public void setChangeTracking(boolean enabled) {
 158                 changeTracking = enabled;
 159         }
 160
 161         private boolean changeTracking = true;
 162
 163         protected Object syncMutex = new Object();
 164
 165
 166         private List<Pair<E,String>> added = new ArrayList<Pair<E,String>>();
 167         private List<Pair<E,String>> removed = new ArrayList<Pair<E,String>>();
 168         private MapSet<E, String> updated = new MapSet.Hash<E, String>();
 169
 170         private boolean rangeModified = false;
 171
 172         public boolean isRangeModified() {
 173         return rangeModified;
 174     }
 175
 176         @Override
 177         public void onChanged() {
 178                 try {
 179                         UndoContext undoContext = undoRedoSupport.getUndoContext(session);
 180                         int ucount = undoContext.getAll().size();
 181                         int rcount = undoContext.getRedoList().size();
 182                         if (DEBUG) System.out.println("Previous U:" + undoOpCount +" R:" + redoOpCount +" Current U:"+ucount+" R:"+rcount);
 183                         if (ucount < undoOpCount) {
 184                                 runUndo = true;
 185                         } else {
 186                                 runUndo = false;
 187                         }
 188                         if (!runUndo && rcount > 0)
 189                                 runRedo = true;
 190                         else
 191                                 runRedo = false;
 192                         undoOpCount = ucount;
 193                         redoOpCount = rcount;
 194
 195                         if (DEBUG) System.out.println("Undo " + runUndo + " Redo " + runRedo);
 196                 } catch (DatabaseException e) {
 197                         // TODO Auto-generated catch block
 198                         e.printStackTrace();
 199                 }
 200
 201
 202         }
 203
 204         @Override
 205         public void updateRenderObjectsFor(E node) {
 206                 List<vtkProp> toDelete = new ArrayList<vtkProp>();
 207                 view.lock();
 208                 for (vtkProp prop : nodeToActor.getValues(node)) {
 209                         if (prop.GetVTKId() != 0) {
 210                                 view.getRenderer().RemoveActor(prop);
 211                                 //prop.Delete();
 212                                 toDelete.add(prop);
 213                         }
 214                         actorToNode.remove(prop);
 215                 }
 216                 view.unlock();
 217                 nodeToActor.remove(node);
 218                 Collection<vtkProp> coll = getActors(node);
 219                 if (coll != null) {
 220                         for (vtkProp prop : coll) {
 221                                 nodeToActor.add(node,prop);
 222                                 actorToNode.put(prop, node);
 223                                 toDelete.remove(prop);
 224                         }
 225                 }
 226                 for (vtkProp p : toDelete)
 227                         p.Delete();
 228         }
 229
 230         protected abstract  Collection<vtkProp> getActors(E node);
 231
 232         @SuppressWarnings("unchecked")
 233         private void receiveAdd(E node, String id, boolean db) {
 234                 if (DEBUG) System.out.println("receiveAdd " + debugString(node)  + " " + id + " " + db);
 235                 synchronized (syncMutex) {
 236                         for (Pair<E, String> n : added) {
 237                                 if (n.first.equals(node))
 238                                         return;
 239                         }
 240                         if (changeTracking) {
 241                                 mapping.rangeModified((E)node.getParent());
 242                                 mapping.rangeModified((E)node);
 243                         }
 244                         added.add(new Pair<E, String>(node, id));
 245                         rangeModified = true;
 246                 }
 247                 repaint();
 248         }
 249
 250         @SuppressWarnings("unchecked")
 251         private void receiveRemove(E node, String id, boolean db) {
 252                 if (DEBUG) System.out.println("receiveRemove " + debugString(node)  + " " + id + " " + db);
 253                 synchronized (syncMutex) {
 254                         for (Pair<E, String> n : removed) {
 255                                 if (n.first.equals(node))
 256                                         return;
 257                         }
 258                         if (changeTracking && !db) {
 259                             mapping.rangeModified((E)node);
 260                                 mapping.rangeModified((E)node.getParent());
 261                         }
 262                         removed.add(new Pair<E, String>(node, id));
 263                         rangeModified = true;
 264                 }
 265                 repaint();
 266         }
 267
 268         private void receiveUpdate(E node, String id, boolean db) {
 269                 if (DEBUG) System.out.println("receiveUpdate " + debugString(node)  + " " + id + " " + db);
 270                 synchronized (syncMutex) {
 271 //          for (Pair<E, String> n : updated) {
 272 //              if (n.first.equals(node))
 273 //                  return;
 274 //          }
 275                         if (changeTracking && !db)
 276                                 mapping.rangeModified(node);
 277                         //updated.add(new Pair<E, String>(node, id));
 278                         updated.add(node, id);
 279                         rangeModified = true;
 280                 }
 281                 repaint();
 282         }
 283
 284         private boolean graphUpdates = false;
 285         private Set<E> graphModified = new HashSet<E>();
 286
 287         private boolean requestCommit = false;
 288         private String commitMessage = null;
 289
 290         @Override
 291         public void commit(String message) {
 292                 requestCommit = true;
 293                 commitMessage = message;
 294         }
 295
 296         protected void doCommit() {
 297                 IProgressService service = PlatformUI.getWorkbench().getProgressService();
 298                 try {
 299                         service.busyCursorWhile(monitor -> {
 300                                 try {
 301                                         session.syncRequest(new WriteRequest() {
 302                                                 @Override
 303                                                 public void perform(WriteGraph graph) throws DatabaseException {
 304                                                         if (DEBUG) System.out.println("Commit " + commitMessage);
 305                                                         if (commitMessage != null) {
 306                                                                 Layer0Utils.addCommentMetadata(graph, commitMessage);
 307                                                                 graph.markUndoPoint();
 308                                                                 commitMessage = null;
 309                                                         }
 310                                                         commit(graph);
 311                                                 }
 312                                         });
 313                                 } catch (DatabaseException e) {
 314                                         ExceptionUtils.logAndShowError("Cannot commit editor changes", e);
 315                                 }
 316                         });
 317                 } catch (InvocationTargetException | InterruptedException e) {
 318                         LOGGER.error("Unexpected exception", e);
 319                 }
 320         }
 321
 322         protected void commit(WriteGraph graph) throws DatabaseException {
 323                 synchronized(syncMutex) {
 324                         if (DEBUG) System.out.println("Commit");
 325                         graphUpdates = true;
 326                         mapping.updateDomain(graph);
 327                         graphUpdates = false;
 328                         clearDeletes();
 329                         if (DEBUG) System.out.println("Commit done");
 330                 }
 331         }
 332
 333
 334
 335         @Override
 336         public void domainModified() {
 337                 if (graphUpdates)
 338                         return;
 339                 if (DEBUG)System.out.println("domainModified");
 340                 session.asyncRequest(new ReadRequest() {
 341
 342                         @Override
 343                         public void run(ReadGraph graph) throws DatabaseException {
 344                                 update(graph);
 345                         }
 346                 });
 347
 348         }
 349
 350         protected void reset(ReadGraph graph) throws MappingException {
 351                 if (DEBUG) System.out.println("Reset");
 352
 353                 graphUpdates = true;
 354                 mapping.getRangeModified().clear();
 355                 for (DBObject o : mapping.getDomain())
 356                         mapping.domainModified(o);
 357                 mapping.updateRange(graph);
 358                 graphModified.clear();
 359                 graphUpdates = false;
 360         }
 361
 362         private boolean useFullSyncWithUndo = false;
 363
 364         protected void update(ReadGraph graph) throws DatabaseException {
 365                 synchronized (syncMutex) {
 366                         if (DEBUG) System.out.println("Graph update start");
 367
 368                         if (runUndo && useFullSyncWithUndo) {
 369                                 reset(graph);
 370                         } else {
 371                                 graphUpdates = true;
 372                                 for (DBObject domainObject : mapping.getDomainModified()) {
 373                                         @SuppressWarnings("unchecked")
 374                                         E rangeObject = (E) mapping.get(domainObject);
 375                                         if (rangeObject != null)
 376                                                 graphModified.add(rangeObject);
 377                                 }
 378                                 mapping.updateRange(graph);
 379                                 graphModified.clear();
 380                                 syncDeletes();
 381                                 clearDeletes();
 382                                 graphUpdates = false;
 383                 }
 384
 385                         if (mapping.isRangeModified() && !runUndo && !runRedo)
 386                                 commit((String)null);
 387
 388                         if (DEBUG) System.out.println("Graph update done");
 389                 }
 390         }
 391
 392         @Override
 393         public void rangeModified() {
 394                 //System.out.println("rangeModified");
 395
 396         }
 397
 398         @Override
 399         public void postRender() {
 400                 // Commit changes if
 401                 // 1. Commit has been requested
 402                 // 2. There are no pending changes that should be processed in preRender()
 403                 if (requestCommit && !rangeModified) { // FIXME : not thread safe.
 404                         requestCommit = false;
 405                         doCommit();
 406                 }
 407         }
 408
 409         // Reusable containers for data synchronisation
 410         List<Pair<E, String>> rem = new ArrayList<Pair<E,String>>();  // Removed objects
 411         List<Pair<E, String>> add = new ArrayList<Pair<E,String>>();  // Added objects
 412         MapSet<E, String> mod = new MapSet.Hash<E, String>();         // Modified objects
 413         Set<E> propagation = new HashSet<E>();                        // Objects with propagated changes
 414         Stack<E> stack = new Stack<E>();                              // Stack for handling propagation
 415         Set<E> delete = Collections.synchronizedSet(new HashSet<E>()); // Objects to be completely deleted
 416         Set<E> deleteUC = new HashSet<E>();
 417
 418         @Override
 419         public synchronized void preRender() {
 420                 updateCycle();
 421         }
 422
 423
 424         /**
 425          * When objects are removed (either from Java or Graph), after remove processing the Java objects remain in mapping cache.
 426          * This causes problems with Undo and Redo, which cause re-using the removed objects from mapping cache.
 427          *
 428          * This code here synchronizes removed and added objects to collect deletable objects. (a deletable object is one which is removed but not added).
 429          *
 430          */
 431         @SuppressWarnings("unused")
 432         protected void syncDeletes() {
 433                 deleteUC.clear();
 434                 for (Pair<E, String> n : removed) {
 435                         deleteUC.add(n.first);
 436                 }
 437                 for (Pair<E, String> n : added) {
 438                         deleteUC.remove(n.first);
 439                 }
 440                 if (DEBUG && deleteUC.size() > 0) {
 441                         System.out.println("Delete sync");
 442                         for (E n : delete) {
 443                                 System.out.println(debugString(n));
 444                         }
 445                 }
 446                 delete.addAll(deleteUC);
 447                 deleteUC.clear();
 448         }
 449
 450         /**
 451          * Clears deletable objects from mapping cache.
 452          */
 453         @SuppressWarnings("unused")
 454         protected void clearDeletes() {
 455                 if (DEBUG && delete.size() > 0) System.out.println("Delete");
 456                 for (E n : delete) {
 457                         if (DEBUG) System.out.println(debugString(n));
 458                         mapping.getRange().remove(n);
 459                         stopListening(n);
 460                 }
 461                 delete.clear();
 462         }
 463
 464         protected String debugString(E n) {
 465                 return n + "@" + Integer.toHexString(n.hashCode());
 466         }
 467
 468         protected boolean filterChange(List<Pair<E,String>> list,E n) {
 469             for (int i = list.size()-1; i >= 0; i--) {
 470             if (list.get(i).first == n) {
 471                 list.remove(i);
 472                 return true;
 473             }
 474         }
 475             return false;
 476         }
 477
 478         @SuppressWarnings("unchecked")
 479         protected void updateCycle() {
 480                 rem.clear();
 481                 add.clear();
 482                 mod.clear();
 483                 propagation.clear();
 484
 485
 486                 synchronized (syncMutex) {
 487                     // Check for overlapping additions and deletions, prevent deleting objects that are also added and vice versa.
 488                     Deque<E> stack = new ArrayDeque<E>();
 489                 for (Pair<E, String> n : added) {
 490                     stack.add(n.first);
 491                 }
 492                 while (!stack.isEmpty()) {
 493                     E n = stack.pop();
 494                     boolean conflict = filterChange(removed, n);
 495                     if (conflict) {
 496                         if (DEBUG) System.out.println("Prevent removing " + n);
 497                         //filterChange(added, n)
 498                         if (filterChange(added, n))
 499                            if (DEBUG) System.out.println("Prevent adding " + n);
 500                     }
 501                     if (n instanceof ParentNode) {
 502                         ParentNode<INode> pn = (ParentNode<INode>)n;
 503                         for (INode cn : pn.getNodes()) {
 504                             stack.push((E)cn);
 505                         }
 506                     }
 507                 }
 508                 // Do not process updates for removed nodes.
 509                 for (Pair<E, String> r : removed) {
 510                     updated.removeValues(r.first);
 511                 }
 512                         rem.addAll(removed);
 513                         add.addAll(added);
 514                         for (E e : updated.getKeys()) {
 515                                 for (String s : updated.getValues(e)) {
 516                                         mod.add(e, s);
 517                                 }
 518                         }
 519                         syncDeletes();
 520                         removed.clear();
 521                         added.clear();
 522                         updated.clear();
 523                 }
 524
 525
 526                 for (Pair<E, String> n : rem) {
 527                         stopListening(n.first);
 528                         removeActor(n.first);
 529                         n.first.remove();
 530                 }
 531
 532             for (Pair<E, String> n : add) {
 533                 addActor(n.first);
 534                 listen(n.first);
 535             }
 536
 537                 for (E e : mod.getKeys()) {
 538                         Set<String> ids = mod.getValues(e);
 539                         if (ids.contains(G3D.URIs.hasPosition) || ids.contains(G3D.URIs.hasOrientation)) {
 540                                 if (!propagation.contains(e))
 541                                         propagation.add(e);
 542                         }
 543                 }
 544
 545                 if (propagation.size() > 0) {
 546                         stack.clear();
 547                         stack.addAll(propagation);
 548                         propagation.clear();
 549                         while (!stack.isEmpty()) {
 550                                 E node = stack.pop();
 551                                 if (propagation.contains(node))
 552                                         continue;
 553                                 propagation.add(node);
 554                                 for (NodeListener l : node.getListeners()) {
 555                                         if (l == this) {
 556                                                 //changeTracking = false;
 557                                                 //l.propertyChanged(node, G3D.URIs.hasPosition);
 558                                                 //changeTracking = true;
 559                                         } else {
 560                                                 l.propertyChanged(node, G3D.URIs.hasWorldPosition);
 561                                         }
 562                                 }
 563                                 if (node instanceof ParentNode) {
 564                                         stack.addAll(((ParentNode<E>)node).getNodes());
 565                                 }
 566                         }
 567                 }
 568
 569                 for (E e : mod.getKeys()) {
 570                         Set<String> ids = mod.getValues(e);
 571                         updateActor(e,ids);
 572                 }
 573
 574                 for (Pair<E, String> n : rem) {
 575                         for (NodeListener l : nodeListeners)
 576                                 l.nodeRemoved(null, n.first, n.second);
 577                 }
 578                 for (Pair<E, String> n : add) {
 579                         for (NodeListener l : nodeListeners)
 580                                 l.nodeAdded(n.first.getParent(), n.first, n.second);
 581                 }
 582 //      for (Pair<E, String> n : mod) {
 583 //          for (NodeListener l : nodeListeners)
 584 //              l.propertyChanged(n.first, n.second);
 585 //      }
 586                 for (E e : mod.getKeys()) {
 587                         for (NodeListener l : nodeListeners)
 588                                 for (String s : mod.getValues(e))
 589                                         l.propertyChanged(e, s);
 590                 }
 591
 592                 synchronized (syncMutex) {
 593                         if (added.isEmpty() && removed.isEmpty() && updated.getKeys().size() == 0)
 594                                 rangeModified = false;
 595                 }
 596         }
 597
 598         @SuppressWarnings("unchecked")
 599         private void listen(INode node) {
 600                 node.addListener(this);
 601                 if (node instanceof ParentNode<?>) {
 602                         ParentNode<INode> parentNode = (ParentNode<INode>)node;
 603                         for (INode n : parentNode.getNodes())
 604                                 listen(n);
 605                 }
 606         }
 607
 608         private void stopListening(INode node) {
 609                 node.removeListener(this);
 610                 if (node instanceof ParentNode<?>) {
 611                         @SuppressWarnings("unchecked")
 612                         ParentNode<INode> parentNode = (ParentNode<INode>)node;
 613                         for (INode n : parentNode.getNodes())
 614                                 stopListening(n);
 615                 }
 616         }
 617
 618         @SuppressWarnings("unchecked")
 619         @Override
 620         public void propertyChanged(INode node, String id) {
 621                 //receiveUpdate((E)node, id, graphUpdates);
 622                 receiveUpdate((E)node, id, graphModified.contains(node));
 623
 624         }
 625
 626         @SuppressWarnings("unchecked")
 627         @Override
 628         public <T extends INode> void nodeAdded(ParentNode<T> node, INode child,
 629                         String rel) {
 630                 if (DEBUG) System.out.println("Node added " + child + " parent " + node);
 631                 //receiveAdd((E)child, rel ,graphUpdates);
 632                 receiveAdd((E)child, rel ,graphModified.contains(node));
 633         }
 634
 635         @SuppressWarnings("unchecked")
 636         @Override
 637         public <T extends INode> void nodeRemoved(ParentNode<T> node, INode child,
 638                         String rel) {
 639                 if (DEBUG) System.out.println("Node removed " + child + " parent " + node);
 640                 //receiveRemove((E)child, rel, graphUpdates);
 641                 receiveRemove((E)child, rel, graphModified.contains(node));
 642
 643                 //FIXME : 1. sometimes removed structural models cause ObjMap to add their children again.
 644                 //           removing the listener here prevents corruption of visual model, but better fix is needed.
 645                 //        2. detach causes nodeRemoved event, which then causes other critical events to be missed. Took out call:
 646                 //stopListening(child);
 647         }
 648
 649         @Override
 650         public void delete() {
 651                 if (undoRedoSupport != null)
 652                         undoRedoSupport.cancel(this);
 653
 654                 changeTracking = false;
 655                 view.removeListener(this);
 656                 mapping.removeMappingListener(this);
 657
 658                 List<E> nodes = new ArrayList<E>(nodeToActor.getKeySize());
 659                 nodes.addAll(nodeToActor.getKeys());
 660                 for (E node : nodes) {
 661                         node.removeListener(this);
 662                         removeActor(node);
 663                         node.cleanup();
 664                 }
 665                 for (vtkProp prop : actorToNode.keySet()) {
 666                         if (prop.GetVTKId() != 0)
 667                                 prop.Delete();
 668                 }
 669                 actorToNode.clear();
 670                 nodeToActor.clear();
 671
 672         }
 673
 674
 675         private List<NodeListener> nodeListeners = new ArrayList<NodeListener>();
 676         @Override
 677         public void addListener(NodeListener listener) {
 678                 nodeListeners.add(listener);
 679
 680         }
 681
 682         @Override
 683         public void removeListener(NodeListener listener) {
 684                 nodeListeners.remove(listener);
 685
 686         }
 687
 688         public IMapping<DBObject,INode> getMapping() {
 689                 return mapping;
 690         }
 691
 692
 693 }