bundles/org.simantics.selectionview/src/org/simantics/selectionview/function/All.java

   1 package org.simantics.selectionview.function;
   2
   3 import java.io.IOException;
   4 import java.util.ArrayList;
   5 import java.util.Collections;
   6 import java.util.Map;
   7 import java.util.function.Consumer;
   8
   9 import org.eclipse.swt.graphics.FontData;
  10 import org.eclipse.swt.graphics.RGB;
  11 import org.eclipse.swt.widgets.ColorDialog;
  12 import org.eclipse.swt.widgets.Control;
  13 import org.eclipse.swt.widgets.FontDialog;
  14 import org.simantics.Simantics;
  15 import org.simantics.browsing.ui.NodeContext;
  16 import org.simantics.browsing.ui.content.Labeler.DialogModifier;
  17 import org.simantics.browsing.ui.graph.impl.GetEnumerationValue;
  18 import org.simantics.common.format.Formatter;
  19 import org.simantics.databoard.Bindings;
  20 import org.simantics.databoard.Datatypes;
  21 import org.simantics.databoard.adapter.AdaptException;
  22 import org.simantics.databoard.binding.Binding;
  23 import org.simantics.databoard.binding.NumberBinding;
  24 import org.simantics.databoard.binding.StringBinding;
  25 import org.simantics.databoard.binding.error.BindingConstructionException;
  26 import org.simantics.databoard.binding.error.BindingException;
  27 import org.simantics.databoard.binding.mutable.MutableStringBinding;
  28 import org.simantics.databoard.binding.mutable.Variant;
  29 import org.simantics.databoard.parser.DataValuePrinter;
  30 import org.simantics.databoard.parser.repository.DataTypeSyntaxError;
  31 import org.simantics.databoard.parser.repository.DataValueRepository;
  32 import org.simantics.databoard.primitives.MutableString;
  33 import org.simantics.databoard.type.Datatype;
  34 import org.simantics.databoard.util.ObjectUtils;
  35 import org.simantics.datatypes.literal.Font;
  36 import org.simantics.db.ReadGraph;
  37 import org.simantics.db.Resource;
  38 import org.simantics.db.Statement;
  39 import org.simantics.db.WriteGraph;
  40 import org.simantics.db.common.CommentMetadata;
  41 import org.simantics.db.common.request.EnumerationMap;
  42 import org.simantics.db.common.request.InstanceEnumerationMap;
  43 import org.simantics.db.common.request.IsEnumeratedValue;
  44 import org.simantics.db.common.request.UniqueRead;
  45 import org.simantics.db.common.request.WriteRequest;
  46 import org.simantics.db.common.utils.NameUtils;
  47 import org.simantics.db.exception.DatabaseException;
  48 import org.simantics.db.layer0.util.Layer0Utils;
  49 import org.simantics.db.layer0.variable.ValueAccessor;
  50 import org.simantics.db.layer0.variable.Variable;
  51 import org.simantics.db.layer0.variable.Variables;
  52 import org.simantics.layer0.Layer0;
  53 import org.simantics.modeling.ModelingResources;
  54 import org.simantics.scl.compiler.types.TVar;
  55 import org.simantics.scl.compiler.types.Type;
  56 import org.simantics.scl.compiler.types.Types;
  57 import org.simantics.scl.reflection.annotations.SCLValue;
  58 import org.simantics.scl.runtime.function.Function1;
  59 import org.simantics.selectionview.SelectionInput;
  60 import org.simantics.selectionview.SelectionViewResources;
  61 import org.simantics.selectionview.StandardSelectionInput;
  62 import org.simantics.ui.colors.Colors;
  63 import org.simantics.ui.fonts.Fonts;
  64 import org.simantics.ui.selection.WorkbenchSelectionElement;
  65 import org.simantics.ui.selection.WorkbenchSelectionUtils;
  66 import org.simantics.utils.datastructures.collections.CollectionUtils;
  67 import org.simantics.utils.strings.AlphanumComparator;
  68 import org.simantics.utils.ui.AdaptionUtils;
  69 import org.simantics.utils.ui.ErrorLogger;
  70 import org.simantics.utils.ui.ISelectionUtils;
  71
  72 public class All {
  73
  74         final private static Binding datatype_binging = Bindings.getBindingUnchecked(Datatype.class);
  75
  76         @SCLValue(type = "ReadGraph -> Resource -> Variable -> b")
  77         public static Object colorModifier(ReadGraph graph, Resource resource, final Variable context) throws DatabaseException {
  78                 return new DialogModifier() {
  79
  80                         @Override
  81                         public String getValue() {
  82                                 return null;
  83                         }
  84
  85                         @Override
  86                         public String isValid(String label) {
  87                                 return null;
  88                         }
  89
  90                         @Override
  91                         public void modify(final String label) {
  92                                 Simantics.getSession().async(new WriteRequest() {
  93
  94                                         @Override
  95                                         public void perform(WriteGraph graph) throws DatabaseException {
  96                                                 Variable displayValue = context.getParent(graph);
  97                                                 displayValue.setValue(graph, label, org.simantics.datatypes.literal.RGB.Integer.BINDING);
  98                                         }
  99
 100                                 });
 101                         }
 102
 103                         public String query(Object parentControl, Object controlItem, int columnIndex, NodeContext context, Consumer<String> applyCallback) {
 104                                 Control ctrl = (Control) parentControl;
 105
 106                                 RGB initialValue = null;
 107                                 final Variable v = AdaptionUtils.adaptToSingle(context, Variable.class);
 108                                 if (v != null) {
 109                                         try {
 110                                                 org.simantics.datatypes.literal.RGB.Integer rgb = Simantics.getSession().syncRequest(new UniqueRead<org.simantics.datatypes.literal.RGB.Integer>() {
 111                                                         @Override
 112                                                         public org.simantics.datatypes.literal.RGB.Integer perform(ReadGraph graph) throws DatabaseException {
 113                                                                 return v.getPossibleValue(graph, org.simantics.datatypes.literal.RGB.Integer.BINDING);
 114                                                         }
 115                                                 });
 116                                                 if (rgb != null) {
 117                                                         initialValue = Colors.rgb(rgb);
 118                                                 }
 119                                         } catch (DatabaseException e) {
 120                                                 ErrorLogger.defaultLogError(e);
 121                                         }
 122                                 }
 123
 124                                 ColorDialog dialog = new ColorDialog(ctrl.getShell());
 125                                 if (initialValue != null)
 126                                         dialog.setRGB(initialValue);
 127                                 RGB rgb = dialog.open();
 128                                 if (rgb != null)
 129                                         applyCallback.accept("(" + rgb.red + "," + rgb.green + "," + rgb.blue + ")");
 130                                 return null;
 131                         }
 132
 133                 };
 134         }
 135
 136         @SCLValue(type = "ReadGraph -> Resource -> Variable -> b")
 137         public static Object fontModifier(ReadGraph graph, Resource resource, final Variable context) throws DatabaseException {
 138                 return new DialogModifier() {
 139
 140                         @Override
 141                         public String getValue() {
 142                                 return null;
 143                         }
 144
 145                         @Override
 146                         public String isValid(String label) {
 147                                 return null;
 148                         }
 149
 150                         @Override
 151                         public void modify(final String label) {
 152                                 Simantics.getSession().async(new WriteRequest() {
 153
 154                                         @Override
 155                                         public void perform(WriteGraph graph) throws DatabaseException {
 156                                                 Variable displayValue = context.getParent(graph);
 157                                                 displayValue.setValue(graph, label, Font.BINDING);
 158                                         }
 159
 160                                 });
 161                         }
 162
 163                         public String query(Object parentControl, Object controlItem, int columnIndex, NodeContext context, Consumer<String> applyCallback) {
 164                                 Control ctrl = (Control) parentControl;
 165
 166                                 FontData[] initialValue = null;
 167                                 final Variable v = AdaptionUtils.adaptToSingle(context, Variable.class);
 168                                 if (v != null) {
 169                                         try {
 170                                                 Font font = Simantics.getSession().syncRequest(new UniqueRead<Font>() {
 171                                                         @Override
 172                                                         public Font perform(ReadGraph graph) throws DatabaseException {
 173                                                                 return v.getPossibleValue(graph, Font.BINDING);
 174                                                         }
 175                                                 });
 176                                                 if (font != null) {
 177                                                         initialValue = new FontData[] { Fonts.swtFontData(font) };
 178                                                 }
 179                                         } catch (DatabaseException e) {
 180                                                 ErrorLogger.defaultLogError(e);
 181                                         }
 182                                 }
 183
 184                                 FontDialog dialog = new FontDialog(ctrl.getShell());
 185                                 if (initialValue != null)
 186                                         dialog.setFontList(initialValue);
 187                                 FontData font = dialog.open();
 188                                 if (font != null)
 189                                         applyCallback.accept("(\"" + font.getName() + "\"," + font.getHeight() + ",\"" + Fonts.fromSwtStyle(font.getStyle()) + "\")");
 190                                 return null;
 191                         }
 192
 193                 };
 194         }
 195
 196         @SCLValue(type = "ReadGraph -> Resource -> a -> b")
 197         public static Object getEnumerationValues(ReadGraph graph, Resource resource, Object context) throws DatabaseException {
 198                 if(context instanceof Variable) {
 199                         Layer0 L0 = Layer0.getInstance(graph);
 200                         Variable parameter = ((Variable)context).browse(graph, "..");
 201                         Resource parameterResource = parameter.getRepresents(graph);
 202                         if(graph.sync(new IsEnumeratedValue(parameterResource))) {
 203                                 Map<String, Resource> map = graph.sync(new InstanceEnumerationMap(parameterResource));
 204                                 ArrayList<String> values = new ArrayList<>(map.keySet());
 205                                 Collections.sort(values, AlphanumComparator.COMPARATOR);
 206                                 return values;
 207                         } else if(graph.isInstanceOf(parameterResource, L0.Boolean)) {
 208                                 return CollectionUtils.toList("true", "false");
 209                         }
 210                 }
 211                 return null;
 212         }
 213
 214         @SCLValue(type = "ReadGraph -> Resource -> a -> b")
 215         public static Object getPropertyChildName(ReadGraph graph, Resource resource, Object context) throws DatabaseException {
 216                 if(context instanceof Variable) {
 217                         Variable variable = (Variable)context;
 218                         String label = variable.getParent(graph).getPossiblePropertyValue(graph, "HasLabel", Bindings.STRING);
 219                         if(label != null)
 220                                 return label;
 221                         return variable.getParent(graph).getName(graph);
 222                 }
 223                 throw new DatabaseException("Unknown context " + context);
 224         }
 225
 226         @SCLValue(type = "WriteGraph -> Variable -> a -> b -> String")
 227         public static String inputModifier(WriteGraph graph, Variable variable, Object value, Object _binding) throws DatabaseException {
 228
 229                 //      System.err.println("inputModifier " + variable.getURI(graph));
 230                 Layer0 L0 = Layer0.getInstance(graph);
 231
 232                 Variable parent = variable.getParent(graph);
 233                 Resource property = variable.getPredicateResource(graph);
 234
 235                 Resource container = parent.getRepresents(graph);
 236                 if(container == null) return null;
 237                 if(property == null) return null;
 238
 239                 Statement object = graph.getPossibleStatement(container, property);
 240                 if(object == null) return null;
 241
 242                 Resource objectResource = object.getObject();
 243                 if(graph.sync(new IsEnumeratedValue(objectResource))) {
 244
 245                         Resource type = graph.getSingleObject(objectResource, L0.PartOf);
 246
 247                         Map<String, Resource> enumMap = graph.syncRequest(new EnumerationMap(type));
 248                         Resource newLiteral = enumMap.get(value);
 249                         graph.deny(container, property, objectResource);
 250                         graph.claim(container, property, newLiteral);
 251
 252                         return null;
 253
 254                 }
 255
 256                 Resource newType = Layer0Utils.getPossibleLiteralType(graph, variable);
 257                 if(newType == null) {
 258                         Type type = Layer0Utils.getSCLType(graph, variable);
 259                         // This means that type is a wildcard e.g. "a"
 260                         if(Types.canonical(type) instanceof TVar) {
 261                                 newType = Layer0Utils.inferLiteralTypeFromString(graph, value.toString());
 262                         } else {
 263                                 throw new DatabaseException("Failed to find type for property " + NameUtils.getSafeName(graph, property));
 264                         }
 265                 }
 266
 267                 boolean correctType = graph.getPossibleType(objectResource, newType) != null;
 268                 boolean asserted = object.isAsserted(container);
 269                 if(asserted || !correctType) {
 270
 271                         if(correctType) {
 272
 273                                 Statement dt = graph.getPossibleStatement(objectResource, L0.HasDataType);
 274                                 Datatype custom = dt.isAsserted(objectResource) ? null : (Datatype)graph.getValue(dt.getObject(), datatype_binging);
 275
 276                                 objectResource = graph.newResource();
 277                                 graph.claim(objectResource, L0.InstanceOf, null, newType);
 278                                 graph.claim(container, property, objectResource);
 279                                 if(custom != null) {
 280                                         // Only set HasValueType if the calculated new SCL type differs from the asserted value type
 281                                         String newValueType = Layer0Utils.getSCLType(custom);
 282                                         String currentValueType = graph.getPossibleRelatedValue(objectResource, L0.HasValueType, Bindings.STRING);
 283                                         if (!newValueType.equals(currentValueType)) {
 284                                                 graph.addLiteral(objectResource, L0.HasValueType, L0.HasValueType_Inverse, L0.String, newValueType, Bindings.STRING);
 285                                         }
 286                                         graph.addLiteral(objectResource, L0.HasDataType, L0.HasDataType_Inverse, L0.DataType, custom, datatype_binging);
 287                                 }
 288
 289                         } else {
 290
 291                                 if(newType != null) {
 292
 293                                         if(!correctType && !asserted) // if not correct type and not asserted, remove the old value
 294                                                 graph.deny(container, property, objectResource);
 295
 296                                         objectResource = graph.newResource();
 297                                         graph.claim(objectResource, L0.InstanceOf, newType);
 298                                         graph.claim(container, property, objectResource);
 299
 300                                 }
 301
 302                         }
 303
 304                 }
 305
 306                 Datatype datatype = variable.getDatatype(graph);
 307                 Binding binding = (Binding)_binding;
 308                 Layer0Utils.claimAdaptedValue(graph, objectResource, value, binding, datatype);
 309
 310                 return null;
 311
 312         }
 313
 314         @SCLValue(type = "ReadGraph -> a -> Resource")
 315         public static Resource singleResourceTransformation(ReadGraph graph, Object input) throws DatabaseException {
 316                 return WorkbenchSelectionUtils.getPossibleResource(graph, input);
 317         }
 318
 319
 320         @SCLValue(type = "ReadGraph -> a -> Variable")
 321         public static Variable singleVariableTransformation(ReadGraph graph, Object input) throws DatabaseException {
 322                 Variable single = WorkbenchSelectionUtils.getPossibleVariable(graph, input);
 323                 if(single != null) return single;
 324                 return ISelectionUtils.filterSingleSelection(input, Variable.class);
 325         }
 326
 327         @SCLValue(type = "ReadGraph -> a -> Variable")
 328         public static Variable singleResourceToVariableTransformation(ReadGraph graph, Object input) throws DatabaseException {
 329                 Resource r = WorkbenchSelectionUtils.getPossibleResource(graph, input);
 330                 if (r == null)
 331                         return null;
 332                 return Variables.getPossibleVariable(graph, r);
 333         }
 334
 335         @SCLValue(type = "ReadGraph -> a -> SelectionInput")
 336         public static SelectionInput standardSelectionInputTransformation(ReadGraph graph, Object input) throws DatabaseException {
 337                 WorkbenchSelectionElement wse = WorkbenchSelectionUtils.getPossibleSelectionElement(input);
 338                 if (wse == null)
 339                         return null;
 340                 return new StandardSelectionInput(wse);
 341         }
 342
 343         @SCLValue(type = "ValueAccessor")
 344         public static ValueAccessor displayUnitValueAccessor = new ValueAccessor() {
 345
 346                 @Override
 347                 public Object getValue(ReadGraph graph, Variable context) throws DatabaseException {
 348                         return Variables.getPossibleUnit(graph, context.getParent(graph));
 349                 }
 350
 351                 @Override
 352                 public Object getValue(ReadGraph graph, Variable context, Binding binding) throws DatabaseException {
 353                         try {
 354                                 Object value = Variables.getPossibleUnit(graph, context.getParent(graph));
 355                                 if(value == null) return null;
 356                                 Binding srcBinding = Bindings.OBJECT.getContentBinding(value);
 357                                 return Bindings.adapt(value, srcBinding, binding);
 358                         } catch (AdaptException e) {
 359                                 throw new DatabaseException(e);
 360                         } catch (BindingException e) {
 361                                 throw new DatabaseException(e);
 362                         }
 363                 }
 364
 365                 @Override
 366                 public void setValue(WriteGraph graph, Variable context, Object value) throws DatabaseException {
 367                         throw new UnsupportedOperationException();
 368                 }
 369
 370                 @Override
 371                 public void setValue(WriteGraph graph, Variable context, Object value, Binding binding) throws DatabaseException {
 372                         throw new UnsupportedOperationException();
 373                 }
 374
 375                 @Override
 376                 public Datatype getDatatype(ReadGraph graph, Variable context) throws DatabaseException {
 377                         return org.simantics.db.layer0.function.All.getDatatypeFromValue(graph, context);
 378                 }
 379
 380         };
 381
 382         @SCLValue(type = "ValueAccessor")
 383         public static ValueAccessor displayPropertyValueAccessor = new ValueAccessor() {
 384
 385                 @Override
 386                 public Object getValue(ReadGraph graph, Variable context) throws DatabaseException {
 387                         return getValue(graph, context, Bindings.STRING);
 388                 }
 389
 390                 @Override
 391                 public Object getValue(ReadGraph graph, Variable context, Binding binding) throws DatabaseException {
 392                         Layer0 L0 = Layer0.getInstance(graph);
 393                         Variable property = context.getParent(graph);
 394                         Resource predicate = property.getPossiblePredicateResource(graph);
 395                         if(predicate == null) return property.getName(graph);
 396                         String value = graph.getPossibleRelatedValue2(predicate, L0.HasLabel, Bindings.STRING);
 397                         if(value == null)
 398                             value = graph.getRelatedValue(predicate, L0.HasName, Bindings.STRING);
 399                         try {
 400                                 return Bindings.adapt(value, binding, Bindings.STRING);
 401                         } catch (AdaptException e) {
 402                                 throw new DatabaseException(e);
 403                         }
 404                 }
 405
 406                 @Override
 407                 public void setValue(WriteGraph graph, Variable context, Object value) throws DatabaseException {
 408                         throw new UnsupportedOperationException();
 409                 }
 410
 411                 @Override
 412                 public void setValue(WriteGraph graph, Variable context, Object value, Binding binding) throws DatabaseException {
 413                         throw new UnsupportedOperationException();
 414                 }
 415
 416                 @Override
 417                 public Datatype getDatatype(ReadGraph graph, Variable context)
 418                                 throws DatabaseException {
 419                         return Datatypes.STRING;
 420                 }
 421
 422         };
 423
 424         @SCLValue(type = "ValueAccessor")
 425         public static ValueAccessor displayValueValueAccessor = new ValueAccessor() {
 426
 427                 @Override
 428                 public Object getValue(ReadGraph graph, Variable context) throws DatabaseException {
 429                         return getValue(graph, context, Bindings.STRING);
 430                 }
 431
 432                 public boolean isPrimitive(Datatype dt) {
 433                         if(Datatypes.STRING.equals(dt)) return true;
 434                         else return false;
 435                 }
 436
 437                 private String possibleExpression(ReadGraph graph, Variable variable) throws DatabaseException {
 438
 439                         Layer0 L0 = Layer0.getInstance(graph);
 440                         Resource object = variable.getPossibleRepresents(graph);
 441                         if(object != null && graph.isInstanceOf(object, L0.SCLValue)) {
 442                                 String expression = graph.getPossibleRelatedValue(object, L0.SCLValue_expression);
 443                                 if (expression != null)
 444                                         return "=" + expression;
 445                         }
 446                         return null;
 447
 448                 }
 449
 450                 @Override
 451                 public Object getValue(ReadGraph graph, Variable context, Binding _binding) throws DatabaseException {
 452
 453                         Variable property = context.getParent(graph);
 454
 455                         String expression = possibleExpression(graph, property);
 456                         if(expression != null) return expression;
 457
 458                         Object value = null;
 459                         Resource formatter = property.getPossiblePropertyValue(graph, Variables.FORMATTER);
 460                         if(formatter != null) {
 461                                 Formatter fmt = graph.adaptContextual(formatter, property, Variable.class, Formatter.class);
 462                                 value = fmt.format(property.getValue(graph));
 463                         }
 464                         if(value == null) {
 465                                 SelectionViewResources SEL = SelectionViewResources.getInstance(graph);
 466                                 Function1<Object,String> formatterFunction = property.getPossiblePropertyValue(graph, SEL.formatter);
 467                                 if(formatterFunction != null) {
 468                                         value = formatterFunction.apply(property.getValue(graph));
 469                                 }
 470                         }
 471
 472                         Resource possibleValue = context.getParent(graph).getPossibleRepresents(graph);
 473                         if(possibleValue != null) {
 474                                 if(graph.syncRequest(new IsEnumeratedValue(possibleValue))) {
 475                                         return GetEnumerationValue.getEnumerationValueName(graph, possibleValue);
 476                                 }
 477                         }
 478
 479                         if(value == null) {
 480
 481                                 Variant variant = property.getVariantValue(graph);
 482                                 value = variant.getValue();
 483                                 Binding binding = variant.getBinding();
 484                                 if(binding != null) {
 485                                         Datatype dt = binding.type();
 486                                         if(dt != null) {
 487                                                 if(!isPrimitive(dt)) {
 488                                                         try {
 489                                                                 value = DataValuePrinter.writeValueSingleLine(binding, value);
 490                                                         } catch (IOException e) {
 491                                                                 e.printStackTrace();
 492                                                         } catch (BindingException e) {
 493                                                                 e.printStackTrace();
 494                                                         }
 495                                                 }
 496                                         }
 497                                 }
 498
 499                         }
 500
 501                         try {
 502                                 return Bindings.adapt(value != null ? value.toString() : "null", _binding, Bindings.STRING);
 503                         } catch (AdaptException e) {
 504                                 throw new DatabaseException(e);
 505                         }
 506                 }
 507
 508                 @Override
 509                 public void setValue(WriteGraph graph, Variable context, Object value) throws DatabaseException {
 510                         try {
 511                                 Binding binding = Bindings.getBinding(value.getClass());
 512                                 setValue(graph, context, value, binding);
 513                         } catch (BindingConstructionException e) {
 514                                 throw new DatabaseException(e);
 515                         }
 516                 }
 517
 518                 @Override
 519                 public void setValue(WriteGraph graph, Variable context, Object _value, Binding _binding) throws DatabaseException {
 520                         try {
 521
 522                                 if(!(_value instanceof String)) throw new DatabaseException("setValue for HasDisplayValue only accepts String (got " + _value.getClass().getSimpleName() + ")");
 523
 524                                 String text = (String)_value;
 525                                 if(text.startsWith("=")) {
 526                                         Variable property = context.getParent(graph);
 527                                         Layer0Utils.setExpression(graph, property, text, ModelingResources.getInstance(graph).SCLValue);
 528                                         return;
 529                                 }
 530
 531                                 String parsedLabel = (String)_value;
 532                                 Object value = parsedLabel;
 533
 534                                 boolean isEnumeration = false;
 535                                 Resource possibleValue = context.getParent(graph).getPossibleRepresents(graph);
 536                                 if(possibleValue != null) {
 537                                         isEnumeration = graph.syncRequest(new IsEnumeratedValue(possibleValue));
 538                                 }
 539
 540                                 Datatype type = context.getParent(graph).getPossibleDatatype(graph);
 541                                 if (type != null && !isEnumeration) {
 542
 543                                         Binding binding = Bindings.getBinding(type);
 544
 545                                         if (binding instanceof StringBinding) {
 546
 547                                                 if (binding instanceof MutableStringBinding)
 548                                                         value = new MutableString(parsedLabel);
 549                                                 else
 550                                                         value = parsedLabel;
 551
 552                                         } else {
 553
 554                                                 if (binding instanceof NumberBinding) {
 555                                                         parsedLabel = parsedLabel.replace(",", ".");
 556                                                 }
 557
 558                                                 value = binding.parseValue(parsedLabel, new DataValueRepository());
 559                                         }
 560
 561                                         //System.out.println("VariableWrite " + ObjectUtils.toString(value));
 562                                         context.getParent(graph).setValue(graph, value, binding);
 563
 564                                 } else {
 565
 566                                         context.getParent(graph).setValue(graph, value);
 567
 568                                 }
 569
 570
 571                                 // Add a comment to metadata.
 572                                 CommentMetadata cm = graph.getMetadata(CommentMetadata.class);
 573                                 graph.addMetadata(cm.add("Set value " + ObjectUtils.toString(value)));
 574
 575                         } catch (DataTypeSyntaxError e) {
 576                                 throw new DatabaseException(e);
 577                         } catch (BindingException e) {
 578                                 throw new DatabaseException(e);
 579                         }
 580                 }
 581
 582                 @Override
 583                 public Datatype getDatatype(ReadGraph graph, Variable context)
 584                                 throws DatabaseException {
 585                         return Datatypes.STRING;
 586                 }
 587
 588         };
 589 }