Module org.jgrapht.io
Package org.jgrapht.nio.json

Class JSONEventDrivenImporter

java.lang.Object
org.jgrapht.nio.BaseEventDrivenImporter<String,Triple<String,String,Double>>
org.jgrapht.nio.json.JSONEventDrivenImporter
All Implemented Interfaces:
EventDrivenImporter<String,Triple<String,String,Double>>
public class JSONEventDrivenImporter extends BaseEventDrivenImporter<String,Triple<String,String,Double>> implements EventDrivenImporter<String,Triple<String,String,Double>>
Imports a graph from a JSON file. Below is a small example of a graph in JSON format. 
 {
   "nodes": [
     { "id": "1" },
     { "id": "2", "label": "Node 2 label" },
     { "id": "3" }
   ],
   "edges": [
     { "source": "1", "target": "2", "weight": 2.0, "label": "Edge between 1 and 2" },
     { "source": "2", "target": "3", "weight": 3.0, "label": "Edge between 2 and 3" }
   ]
 }

In case the graph is weighted then the importer also reads edge weights. Otherwise the default edge weight is returned. The importer also supports reading additional string attributes such as label or custom user attributes.

The parser completely ignores elements from the input that are not related to vertices or edges of the graph. Moreover, complicated nested structures which are inside vertices or edges are simply returned as a whole. For example, in the following graph 

 {
   "nodes": [
     { "id": "1" },
     { "id": "2" }
   ],
   "edges": [
     { "source": "1", "target": "2", "points": { "x": 1.0, "y": 2.0 } }
   ]
 }
the points attribute of the edge is returned as a string containing {"x":1.0,"y":2.0}. The same is done for arrays or any other arbitrary nested structure.
Author:
Dimitrios Michail

  • Field Details

    • DEFAULT_VERTICES_COLLECTION_NAME

      public static final String DEFAULT_VERTICES_COLLECTION_NAME
      Default name for the vertices collection
      See Also:

    • DEFAULT_EDGES_COLLECTION_NAME

      public static final String DEFAULT_EDGES_COLLECTION_NAME
      Default name for the edges collection
      See Also:

  • Constructor Details

    • JSONEventDrivenImporter

      public JSONEventDrivenImporter()
      Constructs a new importer.

    • JSONEventDrivenImporter

      public JSONEventDrivenImporter(boolean notifyVertexAttributesOutOfOrder, boolean notifyEdgeAttributesOutOfOrder)
      Constructs a new importer.
      Parameters:
      notifyVertexAttributesOutOfOrder - whether to notify for vertex attributes out-of-order even if they appear together in the input
      notifyEdgeAttributesOutOfOrder - whether to notify for edge attributes out-of-order even if they appear together in the input

  • Method Details

    • getVerticesCollectionName

      public String getVerticesCollectionName()
      Get the name used for the vertices collection in the file.
      Returns:
      the name used for the vertices collection in the file.

    • setVerticesCollectionName

      public void setVerticesCollectionName(String verticesCollectionName)
      Set the name used for the vertices collection in the file.
      Parameters:
      verticesCollectionName - the name

    • getEdgesCollectionName

      public String getEdgesCollectionName()
      Get the name used for the edges collection in the file.
      Returns:
      the name used for the edges collection in the file.

    • setEdgesCollectionName

      public void setEdgesCollectionName(String edgesCollectionName)
      Set the name used for the edges collection in the file.
      Parameters:
      edgesCollectionName - the name

    • importInput

      public void importInput(Reader input)
      Description copied from interface: EventDrivenImporter
      Import a graph
      Specified by:
      importInput in interface EventDrivenImporter<String,Triple<String,String,Double>>
      Parameters:
      input - the input reader