private SemanticTypeMapping addSemanticTypeStruct(
      ColumnNode sourceColumn, SemanticType semanticType, Set<Node> addedNodes) {

    logger.debug("adding semantic type to the graph ... ");

    if (addedNodes == null) addedNodes = new HashSet<Node>();

    if (semanticType == null) {
      logger.error("semantic type is null.");
      return null;
    }
    if (semanticType.getDomain() == null) {
      logger.error("semantic type does not have any domain");
      return null;
    }

    if (semanticType.getType() == null) {
      logger.error("semantic type does not have any link");
      return null;
    }

    String domainUri = semanticType.getDomain().getUri();
    String propertyUri = semanticType.getType().getUri();
    Double confidence = semanticType.getConfidenceScore();
    Origin origin = semanticType.getOrigin();

    if (domainUri == null || domainUri.isEmpty()) {
      logger.error("semantic type does not have any domain");
      return null;
    }

    if (propertyUri == null || propertyUri.isEmpty()) {
      logger.error("semantic type does not have any link");
      return null;
    }

    logger.debug(
        "semantic type: " + domainUri + "|" + propertyUri + "|" + confidence + "|" + origin);

    InternalNode source = null;
    String nodeId;

    nodeId = nodeIdFactory.getNodeId(domainUri);
    source = new InternalNode(nodeId, new Label(domainUri));
    if (!this.graphBuilder.addNodeAndUpdate(source, addedNodes)) return null;

    nodeId = new RandomGUID().toString();
    ColumnNode target = new ColumnNode(nodeId, nodeId, sourceColumn.getColumnName(), null);
    if (!this.graphBuilder.addNode(target)) return null;
    addedNodes.add(target);

    String linkId = LinkIdFactory.getLinkId(propertyUri, source.getId(), target.getId());
    LabeledLink link;
    if (propertyUri.equalsIgnoreCase(ClassInstanceLink.getFixedLabel().getUri()))
      link = new ClassInstanceLink(linkId);
    else {
      Label label = this.ontologyManager.getUriLabel(propertyUri);
      link = new DataPropertyLink(linkId, label);
    }
    if (!this.graphBuilder.addLink(source, target, link)) return null;

    SemanticTypeMapping mappingStruct =
        new SemanticTypeMapping(sourceColumn, semanticType, source, link, target);

    return mappingStruct;
  }
  @Override
  public void generateJson(String prefix, PrintWriter pw, VWorkspace vWorkspace) {
    Workspace workspace = vWorkspace.getWorkspace();
    alignment = AlignmentManager.Instance().getAlignment(workspace.getId(), worksheetId);
    SemanticTypes types = worksheet.getSemanticTypes();
    Map<String, ColumnNode> hNodeIdTocolumnNodeMap = createColumnNodeMap();
    Map<String, SemanticTypeNode> hNodeIdToDomainNodeMap = createDomainNodeMap();

    JSONStringer jsonStr = new JSONStringer();
    try {
      JSONWriter writer = jsonStr.object();
      writer.key("worksheetId").value(worksheetId).key("updateType").value("SemanticTypesUpdate");

      writer.key(JsonKeys.Types.name());
      writer.array();
      // Iterate through all the columns
      for (HNodePath path : worksheet.getHeaders().getAllPaths()) {
        HNode node = path.getLeaf();
        String nodeId = node.getId();

        writer.object();

        // Check if a semantic type exists for the HNode
        SemanticType type = types.getSemanticTypeForHNodeId(nodeId);
        if (type != null && type.getConfidenceLevel() != SemanticType.ConfidenceLevel.Low) {
          writer
              .key(JsonKeys.HNodeId.name())
              .value(type.getHNodeId())
              .key(JsonKeys.SemanticTypesArray.name())
              .array();

          ColumnNode alignmentColumnNode = hNodeIdTocolumnNodeMap.get(type.getHNodeId());
          SemanticTypeNode domainNode = hNodeIdToDomainNodeMap.get(type.getHNodeId());

          if (alignmentColumnNode == null || domainNode == null) {
            logger.error(
                "Column node or domain node not found in alignment."
                    + " (This should not happen conceptually!):"
                    + type);
            continue;
          }

          // Add the primary semantic type
          writer
              .object()
              .key(JsonKeys.Origin.name())
              .value(type.getOrigin().name())
              .key(JsonKeys.ConfidenceLevel.name())
              .value(type.getConfidenceLevel().name())
              .key(JsonKeys.isPrimary.name())
              .value(true);

          // Add the RDF literal type to show in the text box
          String rdfLiteralType =
              alignmentColumnNode.getRdfLiteralType() == null
                  ? ""
                  : alignmentColumnNode.getRdfLiteralType().getDisplayName();
          String language =
              alignmentColumnNode.getLanguage() == null ? "" : alignmentColumnNode.getLanguage();
          writer.key(JsonKeys.rdfLiteralType.name()).value(rdfLiteralType);
          writer.key(JsonKeys.language.name()).value(language);

          //					String domainDisplayLabel = (domainNode.getLabel().getPrefix() != null &&
          // (!domainNode.getLabel().getPrefix().equals(""))) ?
          //							(domainNode.getLabel().getPrefix() + ":" + domainNode.getLocalId()) :
          // domainNode.getLocalId();
          if (!type.isClass()) {
            writer
                .key(JsonKeys.FullType.name())
                .value(type.getType().getUri())
                .key(JsonKeys.DisplayLabel.name())
                .value(type.getType().getDisplayName())
                .key(JsonKeys.DisplayRDFSLabel.name())
                .value(type.getType().getRdfsLabel())
                .key(JsonKeys.DisplayRDFSComment.name())
                .value(type.getType().getRdfsComment())
                .key(JsonKeys.DomainId.name())
                .value(domainNode.getId())
                .key(JsonKeys.DomainUri.name())
                .value(domainNode.getUri())
                .key(JsonKeys.DisplayDomainLabel.name())
                .value(domainNode.getDisplayId())
                .key(JsonKeys.DomainRDFSLabel.name())
                .value(domainNode.getRdfsLabel())
                .key(JsonKeys.DomainRDFSComment.name())
                .value(domainNode.getRdfsComment());
          } else {
            writer
                .key(JsonKeys.FullType.name())
                .value(domainNode.getId())
                .key(JsonKeys.DisplayLabel.name())
                .value(domainNode.getDisplayId())
                .key(JsonKeys.DisplayRDFSLabel.name())
                .value(domainNode.getRdfsLabel())
                .key(JsonKeys.DisplayRDFSComment.name())
                .value(domainNode.getRdfsComment())
                .key(JsonKeys.DomainId.name())
                .value("")
                .key(JsonKeys.DomainUri.name())
                .value("")
                .key(JsonKeys.DisplayDomainLabel.name())
                .value("")
                .key(JsonKeys.DomainRDFSLabel.name())
                .value("")
                .key(JsonKeys.DomainRDFSComment.name())
                .value("");
          }

          // Mark the special properties
          writer
              .key(JsonKeys.isMetaProperty.name())
              .value(isMetaProperty(type.getType(), alignmentColumnNode));

          writer.endObject();

          // Iterate through the synonym semantic types
          SynonymSemanticTypes synTypes = types.getSynonymTypesForHNodeId(nodeId);

          if (synTypes != null) {
            for (SemanticType synType : synTypes.getSynonyms()) {
              writer
                  .object()
                  .key(JsonKeys.HNodeId.name())
                  .value(synType.getHNodeId())
                  .key(JsonKeys.FullType.name())
                  .value(synType.getType().getUri())
                  .key(JsonKeys.Origin.name())
                  .value(synType.getOrigin().name())
                  .key(JsonKeys.ConfidenceLevel.name())
                  .value(synType.getConfidenceLevel().name())
                  .key(JsonKeys.DisplayLabel.name())
                  .value(synType.getType().getDisplayName())
                  .key(JsonKeys.DisplayRDFSLabel.name())
                  .value(synType.getType().getRdfsLabel())
                  .key(JsonKeys.DisplayRDFSComment.name())
                  .value(synType.getType().getRdfsComment())
                  .key(JsonKeys.isPrimary.name())
                  .value(false);
              if (!synType.isClass()) {
                writer
                    .key(JsonKeys.DomainUri.name())
                    .value(synType.getDomain().getUri())
                    .key(JsonKeys.DomainId.name())
                    .value("")
                    .key(JsonKeys.DisplayDomainLabel.name())
                    .value(synType.getDomain().getDisplayName())
                    .key(JsonKeys.DomainRDFSLabel.name())
                    .value(synType.getDomain().getRdfsLabel())
                    .key(JsonKeys.DomainRDFSComment.name())
                    .value(synType.getDomain().getRdfsComment());
              } else {
                writer
                    .key(JsonKeys.DomainId.name())
                    .value("")
                    .key(JsonKeys.DomainUri.name())
                    .value("")
                    .key(JsonKeys.DisplayDomainLabel.name())
                    .value("")
                    .key(JsonKeys.DomainRDFSLabel.name())
                    .value("")
                    .key(JsonKeys.DomainRDFSComment.name())
                    .value("");
              }
              writer.endObject();
            }
          }
          writer.endArray();
        } else {
          writer.key(JsonKeys.HNodeId.name()).value(nodeId);
          writer.key(JsonKeys.SemanticTypesArray.name()).array().endArray();
        }

        writer.endObject();
      }
      writer.endArray();
      writer.endObject();

      pw.print(writer.toString());
    } catch (JSONException e) {
      logger.error("Error occured while writing to JSON!", e);
    }
  }
  private Set<SemanticTypeMapping> findSemanticTypeInGraph(
      ColumnNode sourceColumn,
      SemanticType semanticType,
      HashMap<String, Integer> semanticTypesCount,
      Set<Node> addedNodes) {

    logger.debug("finding matches for semantic type in the graph ... ");

    if (addedNodes == null) addedNodes = new HashSet<Node>();

    Set<SemanticTypeMapping> mappings = new HashSet<SemanticTypeMapping>();

    if (semanticType == null) {
      logger.error("semantic type is null.");
      return mappings;
    }
    if (semanticType.getDomain() == null) {
      logger.error("semantic type does not have any domain");
      return mappings;
    }

    if (semanticType.getType() == null) {
      logger.error("semantic type does not have any link");
      return mappings;
    }

    String domainUri = semanticType.getDomain().getUri();
    String propertyUri = semanticType.getType().getUri();
    Double confidence = semanticType.getConfidenceScore();
    Origin origin = semanticType.getOrigin();

    Integer countOfSemanticType = semanticTypesCount.get(domainUri + propertyUri);
    if (countOfSemanticType == null) {
      logger.error("count of semantic type should not be null or zero");
      return mappings;
    }

    if (domainUri == null || domainUri.isEmpty()) {
      logger.error("semantic type does not have any domain");
      return mappings;
    }

    if (propertyUri == null || propertyUri.isEmpty()) {
      logger.error("semantic type does not have any link");
      return mappings;
    }

    logger.debug(
        "semantic type: " + domainUri + "|" + propertyUri + "|" + confidence + "|" + origin);

    // add dataproperty to existing classes if sl is a data node mapping
    //		Set<Node> foundInternalNodes = new HashSet<Node>();
    Set<SemanticTypeMapping> semanticTypeMatches =
        this.graphBuilder.getSemanticTypeMatches().get(domainUri + propertyUri);
    if (semanticTypeMatches != null) {
      for (SemanticTypeMapping stm : semanticTypeMatches) {

        SemanticTypeMapping mp =
            new SemanticTypeMapping(
                sourceColumn, semanticType, stm.getSource(), stm.getLink(), stm.getTarget());
        mappings.add(mp);
        //				foundInternalNodes.add(stm.getSource());
      }
    }

    logger.debug("adding data property to the found internal nodes ...");

    Integer count;
    boolean allowMultipleSamePropertiesPerNode =
        ModelingConfigurationRegistry.getInstance()
            .getModelingConfiguration(
                ContextParametersRegistry.getInstance()
                    .getContextParameters(ontologyManager.getContextId())
                    .getKarmaHome())
            .isMultipleSamePropertyPerNode();
    Set<Node> nodesWithSameUriOfDomain = this.graphBuilder.getUriToNodesMap().get(domainUri);
    if (nodesWithSameUriOfDomain != null) {
      for (Node source : nodesWithSameUriOfDomain) {
        count = this.graphBuilder.getNodeDataPropertyCount().get(source.getId() + propertyUri);

        if (count != null) {
          if (allowMultipleSamePropertiesPerNode) {
            if (count >= countOfSemanticType.intValue()) continue;
          } else {
            if (count >= 1) continue;
          }
        }

        String nodeId = new RandomGUID().toString();
        ColumnNode target = new ColumnNode(nodeId, nodeId, sourceColumn.getColumnName(), null);
        if (!this.graphBuilder.addNode(target)) continue;
        ;
        addedNodes.add(target);

        String linkId = LinkIdFactory.getLinkId(propertyUri, source.getId(), target.getId());
        LabeledLink link = new DataPropertyLink(linkId, new Label(propertyUri));
        if (!this.graphBuilder.addLink(source, target, link)) continue;
        ;

        SemanticTypeMapping mp =
            new SemanticTypeMapping(
                sourceColumn, semanticType, (InternalNode) source, link, target);
        mappings.add(mp);
      }
    }

    return mappings;
  }