[−][src]Trait terminus_store::layer::layer::Layer

pub trait Layer: Send + Sync {
    fn name(&self) -> [u32; 5];
    fn parent(&self) -> Option<Arc<dyn Layer>>;
    fn node_and_value_count(&self) -> usize;
    fn predicate_count(&self) -> usize;
    fn subject_id(&self, subject: &str) -> Option<u64>;
    fn predicate_id(&self, predicate: &str) -> Option<u64>;
    fn object_node_id(&self, object: &str) -> Option<u64>;
    fn object_value_id(&self, object: &str) -> Option<u64>;
    fn id_subject(&self, id: u64) -> Option<String>;
    fn id_predicate(&self, id: u64) -> Option<String>;
    fn id_object(&self, id: u64) -> Option<ObjectType>;
    fn subjects(&self) -> Box<dyn Iterator<Item = Box<dyn SubjectLookup>>>;
    fn lookup_subject(&self, subject: u64) -> Option<Box<dyn SubjectLookup>>;
    fn objects(&self) -> Box<dyn Iterator<Item = Box<dyn ObjectLookup>>>;
    fn lookup_object(&self, object: u64) -> Option<Box<dyn ObjectLookup>>;

    fn triple_exists(&self, subject: u64, predicate: u64, object: u64) -> bool { ... }
    fn id_triple_exists(&self, triple: IdTriple) -> bool { ... }
    fn string_triple_exists(&self, triple: &StringTriple) -> bool { ... }
    fn triples(&self) -> Box<dyn Iterator<Item = IdTriple>> { ... }
    fn string_triple_to_id(&self, triple: &StringTriple) -> Option<IdTriple> { ... }
    fn string_triple_to_partially_resolved(
        &self, 
        triple: &StringTriple
    ) -> PartiallyResolvedTriple { ... }
    fn id_triple_to_string(&self, triple: &IdTriple) -> Option<StringTriple> { ... }
    fn is_ancestor_of(&self, other: &dyn Layer) -> bool { ... }
}

A layer containing dictionary entries and triples

A layer can be queried. To answer queries, layers will check their own data structures, and if they have a parent, the parent is queried as well.

Required methods

`fn name(&self) -> [u32; 5]`

The name of this layer

`fn parent(&self) -> Option<Arc<dyn Layer>>`

The parent of this layer, or None if this is a base layer

`fn node_and_value_count(&self) -> usize`

The amount of nodes and values known to this layer This also counts entries in the parent.

`fn predicate_count(&self) -> usize`

The amount of predicates known to this layer This also counts entries in the parent.

`fn subject_id(&self, subject: &str) -> Option<u64>`

The numerical id of a subject, or None if the subject cannot be found

`fn predicate_id(&self, predicate: &str) -> Option<u64>`

The numerical id of a predicate, or None if the predicate cannot be found

`fn object_node_id(&self, object: &str) -> Option<u64>`

The numerical id of a node object, or None if the node object cannot be found

`fn object_value_id(&self, object: &str) -> Option<u64>`

The numerical id of a value object, or None if the value object cannot be found

`fn id_subject(&self, id: u64) -> Option<String>`

The subject corresponding to a numerical id, or None if it cannot be found

`fn id_predicate(&self, id: u64) -> Option<String>`

The predicate corresponding to a numerical id, or None if it cannot be found

`fn id_object(&self, id: u64) -> Option<ObjectType>`

The object corresponding to a numerical id, or None if it cannot be found

`fn subjects(&self) -> Box<dyn Iterator<Item = Box<dyn SubjectLookup>>>`

Returns an iterator over all triple data known to this layer

This data is returned by SubjectLookup. Each such object stores a subject id, and knows how to retrieve any linked predicate-object pair.

`fn lookup_subject(&self, subject: u64) -> Option<Box<dyn SubjectLookup>>`

Returns a SubjectLookup object for the given subject, or None if it cannot be constructed

Note that even if a value is returned here, that doesn't necessarily mean that there will be triples for the given subject. All it means is that this layer or a parent layer has registered an addition involving this subject. However, later layers may have then removed every triple involving this subject.

`fn objects(&self) -> Box<dyn Iterator<Item = Box<dyn ObjectLookup>>>`

Returns an iterator over all objects known to this layer.

Objects are returned as an ObjectLookup, an object that can then be queried for subject-predicate pairs pointing to that object.

`fn lookup_object(&self, object: u64) -> Option<Box<dyn ObjectLookup>>`

Returns an ObjectLookup for the given object, or None if it could not be constructed

Note that even if a value is returned here, that doesn't necessarily mean that there will be triples for the given object. All it means is that this layer or a parent layer has registered an addition involving this object. However, later layers may have then removed every triple involving this object.

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