Package org.jgrapht.nio.gml

Class GmlImporter<V,E>

java.lang.Object

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

org.jgrapht.nio.gml.GmlImporter<V,E>

Type Parameters:

V - the vertex type

E - the edge type

All Implemented Interfaces:

GraphImporter<V,E>

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

Imports a graph from a GML file (Graph Modeling Language).

For a description of the format see http://www.infosun.fmi.uni-passau.de/Graphlet/GML/.

Below is small example of a graph in GML format.

 graph [
   node [ 
     id 1
   ]
   node [
     id 2
     label "Node 2 has an optional label"
   ]
   node [
     id 3
   ]
   edge [
     source 1
     target 2 
     weight 2.0
     label "Edge between 1 and 2"
   ]
   edge [
     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. String attributes are unescaped as if they are Java strings.

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

 graph [
   node [ 
     id 1
   ]
   node [ 
     id 2
   ]
   edge [
     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 ]".

Author:

Dimitrios Michail

Field Summary

Fields

Modifier and Type	Field	Description
static String	DEFAULT_VERTEX_ID_KEY	Default key used for vertex ID.

Constructor Summary

Constructors

Constructor	Description
GmlImporter()	Constructs 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

Field Detail

DEFAULT_VERTEX_ID_KEY

public static final String DEFAULT_VERTEX_ID_KEY

Default key used for vertex ID.

See Also:

Constant Field Values

Constructor Detail

GmlImporter

public GmlImporter()

Constructs 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 GML 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