RdfDataset class final

Represents an immutable RDF dataset containing a default graph and named graphs

An RDF dataset is formally defined as a collection consisting of:

• Exactly one default graph (which may be empty)
• Zero or more named graphs, each identified by an IRI

This class provides functionality for:

• Creating datasets from graphs
• Accessing graphs by name or as collections
• Checking for graph existence
• Iterating over named graphs

The class follows immutability principles - all instances are read-only and operations that would modify the dataset return new instances.

Implementation Notes

• Named graphs are stored in a Map for O(1) lookup by IRI
• The default graph is always present (empty graph if not specified)
• Graph names must be IRIs as per RDF 1.1 specification
• Duplicate graph names are not allowed (Map ensures uniqueness)

Example:

// Create a dataset with both default and named graphs
final dataset = RdfDataset(
  defaultGraph: myDefaultGraph,
  namedGraphs: {
    IriTerm('http://example.org/graph1'): graph1,
    IriTerm('http://example.org/graph2'): graph2,
  },
);

// Access graphs
final graph1 = dataset.graph(IriTerm('http://example.org/graph1'));
final allGraphNames = dataset.graphNames;