Trait GraphRead 

pub trait GraphRead {
    // Required methods
    fn matching_quads<'a>(
        &'a self,
        subject: Option<NamedOrBlankNodeRef<'_>>,
        predicate: Option<NamedNodeRef<'_>>,
        object: Option<TermRef<'_>>,
        graph: Option<GraphNameRef<'_>>,
    ) -> impl Iterator<Item = Result<Quad>> + use<'a, Self>;
    fn named_graphs(
        &self,
    ) -> impl Iterator<Item = Result<NamedOrBlankNode>> + '_;
    fn contains_named_graph(&self, graph: &NamedOrBlankNode) -> Result<bool>;
}

A fallible stream of stored quads, with explicit graph matching.

None matches every graph; Some(DefaultGraph) matches only the default graph. Implementations preserve stored RDF terms and graph contexts. This interface neither constructs a graph union nor copies the base dataset. Storage owners remain responsible for exact-term encoding: a reader cannot recover lexical forms already normalized by its storage backend. During a consistent read, identical patterns must yield the same first quad; no lexical sorting is required. Borrowed views use this stable representative to deduplicate graph contexts without retaining all previously visited triples.

Required Methods

fn matching_quads<'a>( &'a self, subject: Option<NamedOrBlankNodeRef<'_>>, predicate: Option<NamedNodeRef<'_>>, object: Option<TermRef<'_>>, graph: Option<GraphNameRef<'_>>, ) -> impl Iterator<Item = Result<Quad>> + use<'a, Self>

Stream matching quads. Read failures must remain errors, never omissions. Retain the source borrow, not the caller’s temporary pattern references.

fn named_graphs(&self) -> impl Iterator<Item = Result<NamedOrBlankNode>> + '_

Stream each named graph exactly once, including empty backend graphs. Iteration must not materialize the set of graph names.

fn contains_named_graph(&self, graph: &NamedOrBlankNode) -> Result<bool>

Test graph existence, including empty graphs in capable storage backends.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl GraphRead for Dataset

fn matching_quads<'a>( &'a self, subject: Option<NamedOrBlankNodeRef<'_>>, predicate: Option<NamedNodeRef<'_>>, object: Option<TermRef<'_>>, graph: Option<GraphNameRef<'_>>, ) -> impl Iterator<Item = Result<Quad>> + use<'a>

fn named_graphs(&self) -> impl Iterator<Item = Result<NamedOrBlankNode>> + '_

fn contains_named_graph(&self, graph: &NamedOrBlankNode) -> Result<bool>

impl<'tx> GraphRead for Transaction<'tx>

fn matching_quads<'a>( &'a self, subject: Option<NamedOrBlankNodeRef<'_>>, predicate: Option<NamedNodeRef<'_>>, object: Option<TermRef<'_>>, graph: Option<GraphNameRef<'_>>, ) -> impl Iterator<Item = Result<Quad>> + use<'a, 'tx>

fn named_graphs(&self) -> impl Iterator<Item = Result<NamedOrBlankNode>> + '_

fn contains_named_graph(&self, graph: &NamedOrBlankNode) -> Result<bool>

Implementors

impl<'source, G: GraphRead + ?Sized, S: GraphRead + ?Sized> GraphRead for OverlayGraph<'source, G, S>

impl<'source, G: GraphRead + ?Sized> GraphRead for UnionGraph<'source, G>