use schema and predicate types in extractors

1 files changed, 10 insertions, 10 deletions

diff --git a/bsie/extractor/generic/constant.py b/bsie/extractor/generic/constant.py
index e243131..795bac6 100644
--- a/bsie/extractor/generic/constant.py
+++ b/bsie/extractor/generic/constant.py
@@ -7,9 +7,9 @@ Author: Matthias Baumgartner, 2022
 # imports
 import typing
 
-# inner-module imports
+# bsie imports
 from bsie.base import extractor
-from bsie.utils.bsfs import URI
+from bsie.utils.bsfs import URI, schema as _schema
 from bsie.utils.node import Node
 
 # exports
@@ -25,26 +25,26 @@ class Constant(extractor.Extractor):
 
     CONTENT_READER = None
 
+    # predicate/value pairs to be produced.
+    _tuples: typing.Tuple[typing.Tuple[_schema.Predicate, typing.Any], ...]
+
     def __init__(
             self,
             schema: str,
             tuples: typing.Iterable[typing.Tuple[URI, typing.Any]],
             ):
-        self._schema = schema
-        self._tuples = tuples
-        # FIXME: use schema instance for predicate checking
-        #self._tuples = [(pred, value) for pred, value in tuples if pred in schema]
+        super().__init__(_schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + schema))
+        # NOTE: Raises a KeyError if the predicate is not part of the schema
+        self._tuples = tuple((self.schema.predicate(p_uri), value) for p_uri, value in tuples)
         # FIXME: use schema instance for value checking
 
-    def schema(self) -> str:
-        return self._schema
 
     def extract(
             self,
             subject: Node,
             content: None,
-            predicates: typing.Iterable[URI],
-            ) -> typing.Iterator[typing.Tuple[Node, URI, typing.Any]]:
+            predicates: typing.Iterable[_schema.Predicate],
+            ) -> typing.Iterator[typing.Tuple[Node, _schema.Predicate, typing.Any]]:
         for pred, value in self._tuples:
             if pred in predicates:
                 yield subject, pred, value