RDFClosure.Closure.Core

Package RDFClosure :: Module Closure :: Class Core |
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# Class Core

source code

Known Subclasses:
  - RDFSClosure.RDFS_Semantics
  - , OWLRL.OWLRL_Semantics

Core of the semantics management, dealing with the RDFS and other Semantic triples. The only reason to have it in a separate class is for an easier maintainability.

This is a common superclass only. In the present module, it is subclassed by a RDFS Closure class and a OWL RL Closure classes. There are some methods that are implemented in the subclasses only, ie, this class cannot be used by itself!

Instance Methods | [hide private]
__init__(self, graph, axioms, daxioms, rdfs=False) | source code
add_error(self, message) Add an error message | source code
pre_process(self) Do some pre-processing step. | source code
post_process(self) Do some post-processing step. | source code
rules(self, t, cycle_num) The core processing cycles through every tuple in the graph and dispatches it to the various methods implementing a specific group of rules. | source code
add_axioms(self) Add axioms. | source code
add_d_axioms(self) Add d axioms. | source code
one_time_rules(self) This is only a placeholder; subclasses should fill this with real content. | source code
get_literal_value(self, node) Return the literal value corresponding to a Literal node. | source code
empty_stored_triples(self) Empty the internal store for triples | source code
flush_stored_triples(self) Send the stored triples to the graph, and empty the container | source code
store_triple(self, t) In contrast to its name, this does not yet add anything to the graph itself, it just stores the tuple in an internal set. | source code
closure(self) Generate the closure the graph. | source code

Instance Variables | [hide private]
| IMaxNum maximal index of `rdf:_i` occurrence in the graph
set of triples | added_triples triples added to the graph, conceptually, during one processing cycle
boolean | axioms whether axioms should be added or not
boolean | daxioms whether datatype axioms should be added or not
array of strings | error_messages error messages (typically inconsistency messages in OWL RL) found during processing.
rdflib.Graph | graph the real graph
LiteralProxies | literal_proxies Literal Proxies with BNodes for the graph
boolean | rdfs whether RDFS inference is also done (used in subclassed only)

Method Details | [hide private]

### __init__(self, graph, axioms, daxioms, rdfs=False) (Constructor) | source code
Parameters: `graph` (rdflib.Graph) - the RDF graph to be extended `axioms` (boolean) - whether axioms should be added or not `daxioms` (boolean) - whether datatype axioms should be added or not `rdfs` (boolean) - whether RDFS inference is also done (used in subclassed only)

### add_error(self, message) | source code
Add an error message Parameters: `message` (string) - error message

### pre_process(self) | source code
Do some pre-processing step. This method before anything else in the closure. By default, this method is empty, subclasses can add content to it by overriding it.

### post_process(self) | source code
Do some post-processing step. This method when all processing is done, but before handling possible errors (ie, the method can add its own error messages). By default, this method is empty, subclasses can add content to it by overriding it.

### rules(self, t, cycle_num) | source code
The core processing cycles through every tuple in the graph and dispatches it to the various methods implementing a specific group of rules. By default, this method raises an exception; indeed, subclasses must add content to by overriding it. Parameters: `t` (tuple) - one triple on which to apply the rules `cycle_num` - which cycle are we in, starting with 1. This value is forwarded to all local rules; it is also used locally to collect the bnodes in the graph.

### add_axioms(self) | source code
Add axioms. This is only a placeholder and raises an exception by default; subclasses must fill this with real content

### add_d_axioms(self) | source code
Add d axioms. This is only a placeholder and raises an exception by default; subclasses must fill this with real content

### one_time_rules(self) | source code
This is only a placeholder; subclasses should fill this with real content. By default, it is just an empty call. This set of rules is invoked only once and not in a cycle.

### get_literal_value(self, node) | source code
Return the literal value corresponding to a Literal node. Used in error messages. Parameters: `node` - literal node Returns: the literal value itself

### store_triple(self, t) | source code
In contrast to its name, this does not yet add anything to the graph itself, it just stores the tuple in an internal set. (It is important for this to be a set: some of the rules in the various closures may generate the same tuples several times.) Before adding the tuple to the set, the method checks whether the tuple is in the final graph already (if yes, it is not added to the set). The set itself is emptied at the start of every processing cycle; the triples are then effectively added to the graph at the end of such a cycle. If the set is actually empty at that point, this means that the cycle has not added any new triple, and the full processing can stop. Parameters: `t` (a 3-element tuple of (s,p,o)) - the triple to be added to the graph, unless it is already there

### closure(self) | source code
Generate the closure the graph. This is the real 'core'. The processing rules store new triples via the separate method which stores them in the added_triples array. If that array is emtpy at the end of a cycle, it means that the whole process can be stopped. If required, the relevant axiomatic triples are added to the graph before processing in cycles. Similarly the exchange of literals against bnodes is also done in this step (and restored after all cycles are over).

Instance Variable Details | [hide private]

### error_messages error messages (typically inconsistency messages in OWL RL) found during processing. These are added to the final graph at the very end as separate BNodes with error messages Type: array of strings