Package org.jgrapht.nio.graphml

Class GraphMLImporter<V,​E>

  • Type Parameters:
    V - the graph vertex type
    E - the graph edge type
    All Implemented Interfaces:
    GraphImporter<V,​E>
    public class GraphMLImporter<V,​E>
extends BaseEventDrivenImporter<V,​E>
implements GraphImporter<V,​E>
    Imports a graph from a GraphML data source.

    For a description of the format see http://en.wikipedia.org/wiki/ GraphML or the GraphML Primer.

    Below is small example of a graph in GraphML format. 

     
 <?xml version="1.0" encoding="UTF-8"?>
 <graphml xmlns="http://graphml.graphdrawing.org/xmlns"  
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://graphml.graphdrawing.org/xmlns 
     http://graphml.graphdrawing.org/xmlns/1.0/graphml.xsd">
   <key id="d0" for="node" attr.name="color" attr.type="string">
     <default>yellow</default>
   </key>
   <key id="d1" for="edge" attr.name="weight" attr.type="double"/>
   <graph id="G" edgedefault="undirected">
     <node id="n0">
       <data key="d0">green</data>
     </node>
     <node id="n1"/>
     <node id="n2">
       <data key="d0">blue</data>
     </node>
     <node id="n3">
       <data key="d0">red</data>
     </node>
     <node id="n4"/>
     <node id="n5">
       <data key="d0">turquoise</data>
     </node>
     <edge id="e0" source="n0" target="n2">
       <data key="d1">1.0</data>
     </edge>
     <edge id="e1" source="n0" target="n1">
       <data key="d1">1.0</data>
     </edge>
     <edge id="e2" source="n1" target="n3">
       <data key="d1">2.0</data>
     </edge>
     <edge id="e3" source="n3" target="n2"/>
     <edge id="e4" source="n2" target="n4"/>
     <edge id="e5" source="n3" target="n5"/>
     <edge id="e6" source="n5" target="n4">
       <data key="d1">1.1</data>
     </edge>
   </graph>
 </graphml>

    The importer reads the input into a graph which is provided by the user. In case the graph is weighted and the corresponding edge key with attr.name="weight" is defined, the importer also reads edge weights. Otherwise edge weights are ignored. To test whether the graph is weighted, method Graph.getType() can be used.

    GraphML-Attributes Values are read as string key-value pairs and passed on to the vertex or edge attribute consumers respectively.

    The provided graph object, where the imported graph will be stored, must be able to support the features of the graph that is read. For example if the GraphML file contains self-loops then the graph provided must also support self-loops. The same for multiple edges. Moreover, the parser completely ignores the attribute "edgedefault" which denotes whether an edge is directed or not. Whether edges are directed or not depends on the underlying implementation of the user provided graph object.

    The importer by default validates the input using the 1.0 GraphML Schema. The user can (not recommended) disable the validation by calling setSchemaValidation(boolean).

    Author:
    Dimitrios Michail

    • Constructor Detail

      • GraphMLImporter

        public GraphMLImporter()
        Constructs a new importer.

    • Method Detail

      • getEdgeWeightAttributeName

        public String getEdgeWeightAttributeName()
        Get the attribute name for edge weights
        Returns:
        the attribute name

      • setEdgeWeightAttributeName

        public void setEdgeWeightAttributeName​(String edgeWeightAttributeName)
        Set the attribute name to use for edge weights.
        Parameters:
        edgeWeightAttributeName - the attribute name

      • isSchemaValidation

        public boolean isSchemaValidation()
        Whether the importer validates the input
        Returns:
        true if the importer validates the input

      • setSchemaValidation

        public void setSchemaValidation​(boolean schemaValidation)
        Set whether the importer should validate the input
        Parameters:
        schemaValidation - value for schema validation

      • 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 GraphML 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.

        GraphML-Attributes Values are read as string key-value pairs and propagated to the user as events.

        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