1 files changed, 52 insertions, 0 deletions
diff --git a/bsie/extractor/generic/constant.py b/bsie/extractor/generic/constant.py
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+"""The Constant extractor produces pre-specified triples.
+
+Part of the bsie module.
+A copy of the license is provided with the project.
+Author: Matthias Baumgartner, 2022
+"""
+# imports
+import typing
+
+# inner-module imports
+from bsie.base import extractor
+from bsie.utils.bsfs import URI
+from bsie.utils.node import Node
+
+# exports
+__all__: typing.Sequence[str] = (
+    'Constant',
+    )
+
+
+## code ##
+
+class Constant(extractor.Extractor):
+    """Extract information from file's path."""
+
+    CONTENT_READER = None
+
+    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]
+        # 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]]:
+        for pred, value in self._tuples:
+            if pred in predicates:
+                yield subject, pred, value
+
+## EOF ##