bundles/org.simantics.charts/src/org/simantics/charts/internal/JsonUtils.java

   1 package org.simantics.charts.internal;
   2
   3 import java.io.IOException;
   4 import java.util.Optional;
   5
   6 import org.simantics.db.ReadGraph;
   7 import org.simantics.db.RequestProcessor;
   8 import org.simantics.db.common.request.UniqueRead;
   9 import org.simantics.db.exception.DatabaseException;
  10 import org.simantics.db.layer0.variable.Variable;
  11 import org.simantics.db.layer0.variable.Variables;
  12
  13 import com.fasterxml.jackson.core.JsonFactory;
  14 import com.fasterxml.jackson.core.JsonParser;
  15 import com.fasterxml.jackson.core.JsonToken;
  16
  17 /**
  18  * @author Tuukka Lehtonen
  19  *
  20  */
  21 public class JsonUtils {
  22
  23     public static Optional<Variable> tryParseJsonPropertyVariable(RequestProcessor processor, String json) throws DatabaseException {
  24         return processor.syncRequest(new UniqueRead<Optional<Variable>>() {
  25             @Override
  26             public Optional<Variable> perform(ReadGraph graph) throws DatabaseException {
  27                 return tryParseJsonPropertyVariable(graph, json);
  28             }
  29         });
  30     }
  31
  32     public static Optional<Variable> tryParseJsonPropertyVariable(ReadGraph graph, String json) throws DatabaseException {
  33         try (JsonParser jp = new JsonFactory().createParser(json)) {
  34             return JsonUtils.readPossibleVariable(graph, jp);
  35         } catch (IOException e) {
  36             throw new DatabaseException(e);
  37         }
  38     }
  39
  40     public static Optional<Variable> readPossibleVariable(ReadGraph graph, JsonParser jp) throws IOException, DatabaseException {
  41         Optional<String> uri = readPossibleVariableUri(jp);
  42         return uri.isPresent() ? Optional.ofNullable(Variables.getPossibleVariable(graph, uri.get())) : Optional.empty();
  43     }
  44
  45     public static Optional<String> readPossibleVariableUri(JsonParser jp) throws IOException {
  46         // Sanity check: verify that we got "Json Object":
  47         if (jp.nextToken() != JsonToken.START_OBJECT)
  48             throw new IOException("Expected data to start with an Object");
  49
  50         String uri = null;
  51         String type = null;
  52         String defaultPropertyUri = null;
  53
  54         while (jp.nextToken() != JsonToken.END_OBJECT) {
  55             String fieldName = jp.getCurrentName();
  56             jp.nextToken();
  57             if (fieldName.equals("uri")) {
  58                 uri = jp.getValueAsString();
  59             } else if (fieldName.equals("type")) {
  60                 type = jp.getValueAsString();
  61             } else if (fieldName.equals("defaultPropertyUri")) {
  62                 defaultPropertyUri = jp.getValueAsString();
  63             }
  64         }
  65
  66         return Optional.ofNullable("Variable".equals(type) ?
  67                 defaultPropertyUri != null ? defaultPropertyUri : uri
  68                         : null);
  69     }
  70
  71 }