refactor: add is_index_empty API (docarray#1801)

Joan Fontanals · web-flow · commit 3718a747c806 · 2023-09-20T22:25:57.000+02:00
Signed-off-by: Joan Fontanals Martinez &lt;joan.martinez@jina.ai&gt;
diff --git a/docarray/index/abstract.py b/docarray/index/abstract.py
@@ -193,6 +193,14 @@ def num_docs(self) -> int:
         """Return the number of indexed documents"""
         ...
 
+    @property
+    def _is_index_empty(self) -> bool:
+        """
+        Check if index is empty by comparing the number of documents to zero.
+        :return: True if the index is empty, False otherwise.
+        """
+        return self.num_docs() == 0
+
     @abstractmethod
     def _del_items(self, doc_ids: Sequence[str]):
         """Delete Documents from the index.
@@ -1212,7 +1220,7 @@ def subindex_contains(self, item: BaseDoc) -> bool:
         :param item: the given BaseDoc
         :return: if the given BaseDoc item is contained in the index/subindices
         """
-        if self.num_docs() == 0:
+        if self._is_index_empty:
             return False
 
         if safe_issubclass(type(item), BaseDoc):
diff --git a/docarray/index/backends/in_memory.py b/docarray/index/backends/in_memory.py
@@ -195,7 +195,7 @@ def _rebuild_embedding(self):
 
         Note: '_embedding_map' is a dictionary mapping fields to their corresponding embeddings.
         """
-        if self.num_docs() == 0:
+        if self._is_index_empty:
             self._embedding_map = dict()
         else:
             for field_, embedding in self._embedding_map.items():
@@ -361,7 +361,7 @@ def find(
         self._logger.debug(f'Executing `find` for search field {search_field}')
         self._validate_search_field(search_field)
 
-        if self.num_docs() == 0:
+        if self._is_index_empty:
             return FindResult(documents=[], scores=[])  # type: ignore
 
         config = self._column_infos[search_field].config
@@ -414,7 +414,7 @@ def find_batched(
         self._logger.debug(f'Executing `find_batched` for search field {search_field}')
         self._validate_search_field(search_field)
 
-        if self.num_docs() == 0:
+        if self._is_index_empty:
             return FindResultBatched(documents=[], scores=[])  # type: ignore
 
         config = self._column_infos[search_field].config
