Class CSVImporter<V,​E>

Type Parameters:
V - the graph vertex type
E - the graph edge type
All Implemented Interfaces:

public class CSVImporter<V,​E>
extends BaseEventDrivenImporter<V,​E>
implements GraphImporter<V,​E>
Imports a graph from a CSV Format or any other Delimiter-separated value format.

The importer supports various different formats which can be adjusted using the setFormat method. The supported formats are the same CSV formats used by Gephi . For some of the formats, the behavior of the importer can be adjusted using the setParameter method. See CSVFormat for a description of the formats.

The importer respects rfc4180. The caller can also adjust the separator to something like semicolon or pipe instead of comma. In such a case, all fields are unescaped using the new separator. See Delimiter- separated values for more information.

This importer does not distinguish between CSVFormat.EDGE_LIST and CSVFormat.ADJACENCY_LIST. In both cases it assumes the format is CSVFormat.ADJACENCY_LIST.

The graph vertices and edges are build using the corresponding graph suppliers. The id of the vertices in the original file are reported as a vertex attribute named "ID".

The default behavior of the importer is to use the graph vertex supplier in order to create vertices. The user can also bypass vertex creation by providing a custom vertex factory method using setVertexFactory(Function). The factory method is responsible to create a new graph vertex given the vertex identifier read from file.

Dimitrios Michail
See Also:
  • Constructor Details

    • CSVImporter

      public CSVImporter()
      Constructs a new importer using the CSVFormat.ADJACENCY_LIST format as default.
    • CSVImporter

      public CSVImporter​(CSVFormat format)
      Constructs a new importer.
      format - format to use out of the supported ones
    • CSVImporter

      public CSVImporter​(CSVFormat format, char delimiter)
      Constructs a new importer.
      format - format to use out of the supported ones
      delimiter - delimiter to use (comma, semicolon, pipe, etc.)
  • Method Details

    • getFormat

      public CSVFormat getFormat()
      Get the format that the importer is using.
      the input format
    • setFormat

      public void setFormat​(CSVFormat format)
      Set the format of the importer
      format - the format to use
    • getDelimiter

      public char getDelimiter()
      Get the delimiter (comma, semicolon, pipe, etc).
      the delimiter
    • setDelimiter

      public void setDelimiter​(char delimiter)
      Set the delimiter (comma, semicolon, pipe, etc).
      delimiter - the delimiter to use
    • isParameter

      public boolean isParameter​(CSVFormat.Parameter p)
      Return if a particular parameter of the exporter is enabled
      p - the parameter
      true if the parameter is set, false otherwise
    • setParameter

      public void setParameter​(CSVFormat.Parameter p, boolean value)
      Set the value of a parameter of the exporter
      p - the parameter
      value - the value to set
    • getVertexFactory

      public java.util.function.Function<java.lang.String,​V> getVertexFactory()
      Get the user custom vertex factory. This is null by default and the graph supplier is used instead.
      the user custom vertex factory
    • setVertexFactory

      public void setVertexFactory​(java.util.function.Function<java.lang.String,​V> vertexFactory)
      Set the user custom vertex factory. The default behavior is being null in which case the graph vertex supplier is used. If supplied the vertex factory is called every time a new vertex is encountered in the file. The method is called with parameter the vertex identifier from the file and should return the actual graph vertex to add to the graph.
      vertexFactory - a vertex factory
    • importGraph

      public void importGraph​(Graph<V,​E> graph, 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 input 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.

      Specified by:
      importGraph in interface GraphImporter<V,​E>
      graph - the graph
      input - the input reader
      ImportException - in case an error occurs, such as I/O or parse error