1 files changed, 19 insertions, 19 deletions

diff --git a/bsie/extractor/generic/stat.py b/bsie/extractor/generic/stat.py
index d74369c..7088c0a 100644
--- a/bsie/extractor/generic/stat.py
+++ b/bsie/extractor/generic/stat.py
@@ -5,14 +5,13 @@ A copy of the license is provided with the project.
 Author: Matthias Baumgartner, 2022
 """
 # imports
+import os
 import typing
 
-# inner-module imports
+# bsie imports
 from bsie.base import extractor
 from bsie.utils import node, ns
-from bsie.utils.bsfs import URI
-import bsie.reader.stat
-
+from bsie.utils.bsfs import schema as _schema
 
 # exports
 __all__: typing.Sequence[str] = (
@@ -25,32 +24,33 @@ __all__: typing.Sequence[str] = (
 class Stat(extractor.Extractor):
     """Extract information from the file system."""
 
-    CONTENT_READER = bsie.reader.stat.Stat
+    CONTENT_READER = 'bsie.reader.stat.Stat'
 
-    def __init__(self):
-        self.__callmap = {
-            ns.bse.filesize:    self.__filesize,
-            }
+    # mapping from predicate to handler function.
+    _callmap: typing.Dict[_schema.Predicate, typing.Callable[[os.stat_result], typing.Any]]
 
-    def schema(self) -> str:
-        return '''
-            bse:filesize a bsfs:Predicate ;
+    def __init__(self):
+        super().__init__(_schema.Schema.from_string(extractor.SCHEMA_PREAMBLE + '''
+            bse:filesize rdfs:subClassOf bsfs:Predicate ;
                 rdfs:domain bsfs:Entity ;
                 rdfs:range xsd:integer ;
-                rdf:label "File size"^^xsd:string ;
+                rdfs:label "File size"^^xsd:string ;
                 schema:description "File size of entity in some filesystem."^^xsd:string ;
                 owl:maxCardinality "INF"^^xsd:number .
-            '''
+            '''))
+        self._callmap = {
+            self.schema.predicate(ns.bse.filesize): self.__filesize,
+            }
 
     def extract(
             self,
             subject: node.Node,
-            content: CONTENT_READER.CONTENT_TYPE,
-            predicates: typing.Iterable[URI],
-            ) -> typing.Iterator[typing.Tuple[node.Node, URI, typing.Any]]:
+            content: os.stat_result,
+            predicates: typing.Iterable[_schema.Predicate],
+            ) -> typing.Iterator[typing.Tuple[node.Node, _schema.Predicate, typing.Any]]:
         for pred in predicates:
             # find callback
-            clbk = self.__callmap.get(pred)
+            clbk = self._callmap.get(pred)
             if clbk is None:
                 continue
             # get value
@@ -60,7 +60,7 @@ class Stat(extractor.Extractor):
             # produce triple
             yield subject, pred, value
 
-    def __filesize(self, content: CONTENT_READER.CONTENT_TYPE) -> int:
+    def __filesize(self, content: os.stat_result) -> typing.Optional[int]:
         """Return the file size."""
         try:
             return content.st_size