Struct Graph

pub struct Graph { /* private fields */ }

An in-memory RDF graph.

It can accommodate a fairly large number of triples (in the few millions).

It interns the string and does not do any garbage collection yet: if you insert and remove a lot of different terms, memory will grow without any reduction.

Usage example:

use oxrdf::*;

let mut graph = Graph::default();

// insertion
let ex = NamedNodeRef::new("http://example.com")?;
let triple = TripleRef::new(ex, ex, ex);
graph.insert(triple);

// simple filter
let results: Vec<_> = graph.triples_for_subject(ex).collect();
assert_eq!(vec![triple], results);

Implementations

impl Graph

pub fn new() -> Graph

Creates a new graph.

pub fn iter(&self) -> Iter<'_>

Returns all the triples contained by the graph.

pub fn triples_for_subject<'a, 'b>( &'a self, subject: impl Into<SubjectRef<'b>>, ) -> impl Iterator<Item = TripleRef<'a>> + 'a

pub fn objects_for_subject_predicate<'a, 'b>( &'a self, subject: impl Into<SubjectRef<'b>>, predicate: impl Into<NamedNodeRef<'b>>, ) -> impl Iterator<Item = TermRef<'a>> + 'a

pub fn object_for_subject_predicate<'a, 'b>( &'a self, subject: impl Into<SubjectRef<'b>>, predicate: impl Into<NamedNodeRef<'b>>, ) -> Option<TermRef<'a>>

pub fn predicates_for_subject_object<'a, 'b>( &'a self, subject: impl Into<SubjectRef<'b>>, object: impl Into<TermRef<'b>>, ) -> impl Iterator<Item = NamedNodeRef<'a>> + 'a

pub fn triples_for_predicate<'a, 'b>( &'a self, predicate: impl Into<NamedNodeRef<'b>>, ) -> impl Iterator<Item = TripleRef<'a>> + 'a

pub fn subjects_for_predicate_object<'a, 'b>( &'a self, predicate: impl Into<NamedNodeRef<'b>>, object: impl Into<TermRef<'b>>, ) -> impl Iterator<Item = SubjectRef<'a>> + 'a

pub fn subject_for_predicate_object<'a, 'b>( &'a self, predicate: impl Into<NamedNodeRef<'b>>, object: impl Into<TermRef<'b>>, ) -> Option<SubjectRef<'a>>

pub fn triples_for_object<'a, 'b>( &'a self, object: impl Into<TermRef<'b>>, ) -> impl Iterator<Item = TripleRef<'a>> + 'a

pub fn contains<'a>(&self, triple: impl Into<TripleRef<'a>>) -> bool

Checks if the graph contains the given triple.

pub fn len(&self) -> usize

Returns the number of triples in this graph.

pub fn is_empty(&self) -> bool

Checks if this graph contains a triple.

pub fn insert<'a>(&mut self, triple: impl Into<TripleRef<'a>>) -> bool

Adds a triple to the graph.

pub fn remove<'a>(&mut self, triple: impl Into<TripleRef<'a>>) -> bool

Removes a concrete triple from the graph.

pub fn clear(&mut self)

Clears the graph.

pub fn canonicalize(&mut self, algorithm: CanonicalizationAlgorithm)

Canonicalizes the dataset by renaming blank nodes.

Usage example (Graph isomorphism):

use oxrdf::graph::CanonicalizationAlgorithm;
use oxrdf::*;

let iri = NamedNodeRef::new("http://example.com")?;

let mut graph1 = Graph::new();
let bnode1 = BlankNode::default();
graph1.insert(TripleRef::new(iri, iri, &bnode1));
graph1.insert(TripleRef::new(&bnode1, iri, iri));

let mut graph2 = Graph::new();
let bnode2 = BlankNode::default();
graph2.insert(TripleRef::new(iri, iri, &bnode2));
graph2.insert(TripleRef::new(&bnode2, iri, iri));

assert_ne!(graph1, graph2);
graph1.canonicalize(CanonicalizationAlgorithm::Unstable);
graph2.canonicalize(CanonicalizationAlgorithm::Unstable);
assert_eq!(graph1, graph2);

Blank node ids depends on the current shape of the graph. Adding a new quad might change the ids of a lot of blank nodes. Hence, this canonization might not be suitable for diffs.

This implementation worst-case complexity is in *O(b!)* with *b* the number of blank nodes in the input dataset.

Trait Implementations

impl Clone for Graph

fn clone(&self) -> Graph

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Graph

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl Default for Graph

fn default() -> Graph

Returns the “default value” for a type.

impl Display for Graph

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'a, T> Extend<T> for Graph

where T: Into<TripleRef<'a>>,

fn extend<I>(&mut self, iter: I)

where I: IntoIterator<Item = T>,

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Extend<Triple> for Graph

fn extend<I>(&mut self, iter: I)

where I: IntoIterator<Item = Triple>,

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<'a, T> FromIterator<T> for Graph

where T: Into<TripleRef<'a>>,

fn from_iter<I>(iter: I) -> Graph

where I: IntoIterator<Item = T>,

Creates a value from an iterator.

impl FromIterator<Triple> for Graph

fn from_iter<I>(iter: I) -> Graph

where I: IntoIterator<Item = Triple>,

Creates a value from an iterator.

impl<'a> IntoIterator for &'a Graph

type Item = TripleRef<'a>

The type of the elements being iterated over.

type IntoIter = Iter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> <&'a Graph as IntoIterator>::IntoIter

Creates an iterator from a value.

impl PartialEq for Graph

fn eq(&self, other: &Graph) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Graph