Package org.jgrapht.nio.json

Class JSONImporter<V,E>

java.lang.Object

org.jgrapht.nio.BaseEventDrivenImporter<V,E>

org.jgrapht.nio.json.JSONImporter<V,E>

Type Parameters:

V - the vertex type

E - the edge type

All Implemented Interfaces:

GraphImporter<V,E>

public class JSONImporter<V,E>
extends BaseEventDrivenImporter<V,E>
implements GraphImporter<V,E>

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 edge weights are ignored. 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

Constructor Summary

Constructors

Constructor	Description
JSONImporter()	Construct a new importer

Method Summary

Modifier and Type	Method	Description
void	importGraph(Graph<V,E> graph, Reader input)	Import a graph.

Methods inherited from class org.jgrapht.nio.BaseEventDrivenImporter

addEdgeAttributeConsumer, addEdgeConsumer, addEdgeCountConsumer, addGraphAttributeConsumer, addImportEventConsumer, addVertexAttributeConsumer, addVertexConsumer, addVertexCountConsumer, notifyEdge, notifyEdgeAttribute, notifyEdgeCount, notifyGraphAttribute, notifyImportEvent, notifyVertex, notifyVertexAttribute, notifyVertexCount, removeEdgeAttributeConsumer, removeEdgeConsumer, removeEdgeCountConsumer, removeGraphAttributeConsumer, removeImportEventConsumer, removeVertexAttributeConsumer, removeVertexConsumer, removeVertexCountConsumer

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.jgrapht.nio.GraphImporter

importGraph, importGraph

Constructor Detail

JSONImporter

public JSONImporter()

Construct a new importer

Method Detail

importGraph

public void importGraph(Graph<V,E> graph,
                        Reader input)

Import a graph.

The provided graph must be able to support the features of the graph that is read. For example if the file contains self-loops then the graph provided must also support self-loops. The same for multiple edges.

If the provided graph is a weighted graph, the importer also reads edge weights. Otherwise edge weights are ignored.

Specified by:

importGraph in interface GraphImporter<V,E>

Parameters:

graph - the output graph

input - the input reader

Throws:

ImportException - in case an error occurs, such as I/O or parse error