add adapter interface and memory adapter

rltk/io/__init__.py

@@ -1,3 +1,5 @@
 from rltk.io.reader import Reader
 from rltk.io.csv_reader import CSVReader
 from rltk.io.jsonlines_reader import JsonLinesReader
+from rltk.io.adapter import Adapter
+from rltk.io.memory_adapter import MemoryAdapter

rltk/io/adapter.py

@@ -0,0 +1,22 @@
+from rltk.record import Record
+
+
+class Adapter(object):
+    def __init__(self):
+        pass
+
+    def __del__(self):
+        pass
+
+    def get(self, record_id) -> Record:
+        raise NotImplementedError
+
+    def set(self, record_id, record: Record):
+        raise NotImplementedError
+
+    def __iter__(self):
+        return self.__next__()
+
+    def __next__(self):
+        """iterator is not required in adapter"""
+        pass

rltk/io/csv_reader.py

@@ -7,26 +7,15 @@
 class CSVReader(Reader):
 
     def __init__(self, filename, **kwargs):
-        self._filename = filename
-        self._kwargs = kwargs
-        self._loop_count = 0
-
         self._file_handler = codecs.open(filename)
         self._csv_reader = csv.DictReader(self._file_handler, **kwargs)
 
     def __next__(self):
         for obj in self._csv_reader:
-            self._loop_count += 1
             yield {t[0]: t[1] for t in obj.items()}
 
     def __del__(self):
         try:
             self._file_handler.close()
         except:
             pass
-
-    def __copy__(self):
-        new_reader = CSVReader(self._filename, **self._kwargs)
-        while new_reader._loop_count < self._loop_count:
-            new_reader.__next__()
-        return new_reader

rltk/io/memory_adapter.py

@@ -11,3 +11,7 @@ def get(self, record_id):
 
     def set(self, record_id, record: Record):
         self._records[record_id] = record
+
+    def __next__(self):
+        for r in self._records.values():
+            yield r