org.jgrapht.io

Class JSONImporter<V,E>

java.lang.Object

org.jgrapht.io.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 Object
implements GraphImporter<V,E>

Imports a graph from a JSON file. Below is a small example of a graph in GML 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

Field Summary

Fields

Modifier and Type	Field and Description
protected EdgeProvider<V,E>	edgeProvider Constructs new edges
protected ComponentUpdater<Graph<V,E>>	graphUpdater Updates graph properties
protected VertexProvider<V>	vertexProvider Constructs new vertices
protected ComponentUpdater<V>	vertexUpdater Updates already constructed vertices

Constructor Summary

Constructors

Constructor and Description
JSONImporter(VertexProvider<V> vertexProvider, EdgeProvider<V,E> edgeProvider) Constructs a new importer.

Method Summary

Modifier and Type	Method and Description
EdgeProvider<V,E>	getEdgeProvider() Get the edge provider
ComponentUpdater<Graph<V,E>>	getGraphUpdater() Get the graph updater.
VertexProvider<V>	getVertexProvider() Get the vertex provider
ComponentUpdater<V>	getVertexUpdater() Get the vertex updater
void	importGraph(Graph<V,E> graph, Reader input) Import a graph.
void	setEdgeProvider(EdgeProvider<V,E> edgeProvider) Set the edge provider.
void	setGraphUpdater(ComponentUpdater<Graph<V,E>> graphUpdater) Set the graph updater.
void	setVertexProvider(VertexProvider<V> vertexProvider) Set the vertex provider
void	setVertexUpdater(ComponentUpdater<V> vertexUpdater) Set the vertex updater.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jgrapht.io.GraphImporter

importGraph, importGraph

Field Detail

vertexProvider

protected VertexProvider<V> vertexProvider

Constructs new vertices

edgeProvider

protected EdgeProvider<V,E> edgeProvider

Constructs new edges

vertexUpdater

protected ComponentUpdater<V> vertexUpdater

Updates already constructed vertices

graphUpdater

protected ComponentUpdater<Graph<V,E>> graphUpdater

Updates graph properties

Constructor Detail

JSONImporter

public JSONImporter(VertexProvider<V> vertexProvider,
                    EdgeProvider<V,E> edgeProvider)

Constructs a new importer.

Parameters:

vertexProvider - provider for the generation of vertices. Must not be null.

edgeProvider - provider for the generation of edges. Must not be null.

Method Detail

importGraph

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

Import a graph.

The provided graph must be able to support the features of the graph that is read. For example if the JSON 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

getVertexProvider

public VertexProvider<V> getVertexProvider()

Get the vertex provider

Returns:

the vertex provider

setVertexProvider

public void setVertexProvider(VertexProvider<V> vertexProvider)

Set the vertex provider

Parameters:

vertexProvider - the new vertex provider. Must not be null.

getEdgeProvider

public EdgeProvider<V,E> getEdgeProvider()

Get the edge provider

Returns:

The edge provider

setEdgeProvider

public void setEdgeProvider(EdgeProvider<V,E> edgeProvider)

Set the edge provider.

Parameters:

edgeProvider - the new edge provider. Must not be null.

getVertexUpdater

public ComponentUpdater<V> getVertexUpdater()

Get the vertex updater

Returns:

the vertex updater

setVertexUpdater

public void setVertexUpdater(ComponentUpdater<V> vertexUpdater)

Set the vertex updater.

Parameters:

vertexUpdater - the new vertex updater. Must not be null.

getGraphUpdater

public ComponentUpdater<Graph<V,E>> getGraphUpdater()

Get the graph updater.

Returns:

the graph updater

setGraphUpdater

public void setGraphUpdater(ComponentUpdater<Graph<V,E>> graphUpdater)

Set the graph updater.

Parameters:

graphUpdater - the new graph updater. Must not be null.