SYNOPSIS
# see documentation of methods
DESCRIPTION
This describes the minimal interface an ontology query engine should provide. It intentionally does not make explicit references to the ontology being a DAG, nor does it mandate that the ontology be a vocabulary. Rather, it tries to generically express what should be accessible (queriable) about an ontology.The idea is to allow for different implementations for different purposes, which may then differ as to which operations are efficient and which are not, and how much richer the functionality is on top of this minimalistic set of methods. Check modules in the Bio::Ontology namespace to find out which implementations exist. At the time of writing, there is a SimpleOntologyEngine (which does not use Graph.pm), and a Graph.pm-based implementation in SimpleGOEngine.
Ontology parsers in Bio::OntologyIO are required to return an implementation of this interface.
FEEDBACK
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AUTHOR - Peter Dimitrov
Email [email protected]APPENDIX
The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _add_term
Title : add_term Usage : add_term(TermI term): TermI Function: Adds TermI object to the ontology engine term store Example : $oe->add_term($term) Returns : its argument. Args : object of class TermI.
add_relationship
Title : add_relationship Usage : add_relationship(RelationshipI relationship): RelationshipI Function: Adds a relationship object to the ontology engine. Example : Returns : Its argument. Args : A RelationshipI object.
add_relationship_type
Title : add_relationship_type
Usage : add_relationship_type(scalar,OntologyI ontology)
Function: Adds a relationshiptype object to the ontology engine.
Example :
Returns : 1 on success, undef on failure
Args : The name(scalar) of the relationshiptype, and the OntologyI
it is to be added to.
get_relationship_type
Title : get_relationship_type Usage : get_relationship_type(scalar): RelationshipTypeI Function: Get a relationshiptype object from the ontology engine. Example : Returns : A RelationshipTypeI object. Args : The name (scalar) of the RelationshipTypeI object desired.
get_relationships
Title : get_relationships
Usage : get_relationships(TermI term): RelationshipI
Function: Retrieves all relationship objects from this ontology engine,
or all relationships of a term if a term is supplied.
Example :
Returns : Array of Bio::Ontology::RelationshipI objects
Args : None, or a Bio::Ontology::TermI compliant object for which
to retrieve the relationships.
get_predicate_terms
Title : get_predicate_terms Usage : get_predicate_terms(): TermI Function: Example : Returns : Args :
get_child_terms
Title : get_child_terms
Usage : get_child_terms(TermI term, TermI predicate_terms): TermI
Function: Retrieves all child terms of a given term, that satisfy a
relationship among those that are specified in the second
argument or undef otherwise. get_child_terms is a special
case of get_descendant_terms, limiting the search to the
direct descendants.
Example :
Returns : Array of TermI objects.
Args : First argument is the term of interest, second is the list
of relationship type terms.
get_descendant_terms
Title : get_descendant_terms
Usage : get_descendant_terms(TermI term, TermI rel_types): TermI
Function: Retrieves all descendant terms of a given term, that
satisfy a relationship among those that are specified in
the second argument or undef otherwise.
Example :
Returns : Array of TermI objects.
Args : First argument is the term of interest, second is the list
of relationship type terms.
get_parent_terms
Title : get_parent_terms
Usage : get_parent_terms(TermI term, TermI predicate_terms): TermI
Function: Retrieves all parent terms of a given term, that satisfy a
relationship among those that are specified in the second
argument or undef otherwise. get_parent_terms is a special
case of get_ancestor_terms, limiting the search to the
direct ancestors.
Example :
Returns : Array of TermI objects.
Args : First argument is the term of interest, second is the list
of relationship type terms.
get_ancestor_terms
Title : get_ancestor_terms
Usage : get_ancestor_terms(TermI term, TermI predicate_terms): TermI
Function: Retrieves all ancestor terms of a given term, that satisfy
a relationship among those that are specified in the second
argument or undef otherwise.
Example :
Returns : Array of TermI objects.
Args : First argument is the term of interest, second is the list
of relationship type terms.
get_leaf_terms
Title : get_leaf_terms
Usage : get_leaf_terms(): TermI
Function: Retrieves all leaf terms from the ontology. Leaf term is a
term w/o descendants.
Example : @leaf_terms = $obj->get_leaf_terms()
Returns : Array of TermI objects.
Args :
get_root_terms
Title : get_root_terms
Usage : get_root_terms(): TermI
Function: Retrieves all root terms from the ontology. Root term is a
term w/o ancestors.
Example : @root_terms = $obj->get_root_terms()
Returns : Array of TermI objects.
Args :
Factory for relationships and terms
relationship_factory
Title : relationship_factory
Usage : $fact = $obj->relationship_factory()
Function: Get (and set, if the implementation supports it) the object
factory to be used when relationship objects are created by
the implementation on-the-fly.
Example :
Returns : value of relationship_factory (a Bio::Factory::ObjectFactory
compliant object)
Args :
term_factory
Title : term_factory
Usage : $fact = $obj->term_factory()
Function: Get (and set, if the implementation supports it) the object
factory to be used when term objects are created by
the implementation on-the-fly.
Example :
Returns : value of term_factory (a Bio::Factory::ObjectFactory
compliant object)
Args :
Decorator Methods
These methods come with a default implementation that uses the abstract methods defined for this interface. This may not be very efficient, and hence implementors are encouraged to override these methods if they can provide more efficient implementations.
get_all_terms
Title : get_all_terms
Usage : get_all_terms: TermI
Function: Retrieves all terms from the ontology.
This is more a decorator method. We provide a default
implementation here that loops over all root terms and gets
all descendants for each root term. The overall union of
terms is then made unique by name and ontology.
We do not mandate an order here in which the terms are
returned. In fact, the default implementation will return
them in unpredictable order.
Engine implementations that can provide a more efficient
method for obtaining all terms should definitely override
this.
Example : @terms = $obj->get_all_terms()
Returns : Array of TermI objects.
Args :
find_terms
Title : find_terms
Usage : ($term) = $oe->find_terms(-identifier => "SO:0000263");
Function: Find term instances matching queries for their attributes.
An implementation may not support querying for arbitrary
attributes, but can generally be expected to accept
-identifier and -name as queries. If both are provided,
they are implicitly intersected.
Example :
Returns : an array of zero or more Bio::Ontology::TermI objects
Args : Named parameters. The following parameters should be recognized
by any implementation:
-identifier query by the given identifier
-name query by the given name
Experimental API method proposals
Ontologies are a very new domain in bioperl, and we are not sure yet what we will want to do on and with ontologies in which situation. The methods from here on downwards are solely API descriptions to solicit comment and feedback; the chance of any of those being actually implemented already is very slim. Disclaimer: As long as an API method stays in this section, it is subject to change, possibly even radical change or complete deletion. If it's not implemented yet (most likely it isn't), implement yourself at your own risk. So far for the disclaimer. The reason the API description is here, however, is to solicit feedback. Please feel encouraged to share your opinion, regardless of what it is (a notable difference of this API method to others is that there is actually no working code behind it - so the defense line is non-existent for practical purposes).
common_ancestor_path
Title : common_ancestor_path
Usage :
Function: Get the paths from two terms A and B to term C, such that
there is no other term D to which A and B would have a shorter
path, provided there is a term C to which both A and B are
connected by a path.
Note that the path to the common ancestor between A and A
exists, has distance zero, and predicate "identity".
The search for the common ancestor C can be further
constrained by supplying a predicate term. If supplied, the
predicates of the two paths (A,C) and (B,C) must have a
common ancestor identical to the predicate, or that has a
path to the predicate.
Example :
Returns : The path of the first term to the common ancestor in scalar
context, and both paths in list context. Paths are
Bio::Ontology::PathI compliant objects.
Args : The two terms (Bio::Ontology::TermI objects), and optionally
a constraining common predicate (Bio::Ontology::TermI object).
The latter may also be given as a scalar, in which case it
is treated as a boolean that, if TRUE, means that the two paths
must have identical predicates in order to be returned.