graphdb/src/main/java/com/orientechnologies/orient/graph/graphml/OGraphSONUtility.java
public static Edge edgeFromJson(final JSONObject json, final Vertex out, final Vertex in, final ElementFactory factory,
      final GraphSONMode mode, final Set<String> propertyKeys) throws IOException {
    final OGraphSONUtility graphson = new OGraphSONUtility(mode, factory, null, propertyKeys);
    return graphson.edgeFromJson(json, out, in);
  }
public static Edge edgeFromJson(final JSONObject json, final Vertex out, final Vertex in, final ElementFactory factory,
      final GraphSONMode mode, final Set<String> propertyKeys) throws IOException {
    final OGraphSONUtility graphson = new OGraphSONUtility(mode, factory, null, propertyKeys);
    return graphson.edgeFromJson(json, out, in);
  }
Reads an individual Edge from JSON. The edge must match the accepted GraphSON format.

@param json
a single edge in GraphSON format as a Jettison JSONObject
@param factory
the factory responsible for constructing graph elements
@param mode
the mode of the GraphSON
@param propertyKeys
a list of keys to include when reading of element properties