Added system adapter for case when database is empty.

This is a new adapter that is now added by default when a new
bot is created. The adapter is given the highest priority and
will return a confidence value based on if there is data in
the database.

chatterbot/adapters/adaptation.py

@@ -22,6 +22,9 @@ def __init__(self, **kwargs):
         self.logic = MultiLogicAdapter(**kwargs)
         self.logic.set_context(self)
 
+        # Add required system adapter
+        self.add_adapter("chatterbot.adapters.logic.NoKnowledgeAdapter")
+
     def add_adapter(self, adapter, **kwargs):
         NewAdapter = import_module(adapter)
 

chatterbot/adapters/logic/__init__.py

@@ -2,3 +2,4 @@
 from .closest_match import ClosestMatchAdapter
 from .closest_meaning import ClosestMeaningAdapter
 from .multi_adapter import MultiLogicAdapter
+from .no_knowledge_adapter import NoKnowledgeAdapter

chatterbot/adapters/logic/base_match.py

@@ -44,6 +44,14 @@ def get(self, input_statement, statement_list=None):
         """
         raise AdapterNotImplementedError()
 
+    def can_process(self, statement):
+        """
+        Override the can_process method to check if the
+        storage context is available and there is at least
+        one statement in the database.
+        """
+        return self.has_storage_context and self.context.storage.count()
+
     def process(self, input_statement):
 
         # Select the closest match to the input statement

chatterbot/adapters/logic/logic.py

@@ -8,6 +8,15 @@ class LogicAdapter(Adapter):
     that all logic adapters should implement.
     """
 
+    def can_process(self, statement):
+        """
+        A preliminary check that is called to determine if a
+        logic adapter can process a given statement. By default,
+        this method returns true but it can be overridden in
+        child classes as needed.
+        """
+        return True
+
     def process(self, statement):
         """
         Method that takes an input statement and returns

chatterbot/adapters/logic/multi_adapter.py

@@ -17,10 +17,11 @@ def process(self, statement):
         max_confidence = -1
 
         for adapter in self.adapters:
-            confidence, output = adapter.process(statement)
-            if confidence > max_confidence:
-                result = output
-                max_confidence = confidence
+            if adapter.can_process(statement):
+                confidence, output = adapter.process(statement)
+                if confidence > max_confidence:
+                    result = output
+                    max_confidence = confidence
 
         return max_confidence, result
 

chatterbot/adapters/logic/no_knowledge_adapter.py

@@ -0,0 +1,23 @@
+from .logic import LogicAdapter
+
+
+class NoKnowledgeAdapter(LogicAdapter):
+    """
+    This is a system adapter that is automatically added
+    to the list of logic adapters durring initialization.
+    This adapter is placed at the beginning of the list
+    to be given the highest priority.
+    """
+
+    def process(self, statement):
+        """
+        If there are no known responses in the database,
+        then a confidence of 1 should be returned with
+        the input statement.
+        Otherwise, a confidence of 0 should be returned.
+        """
+
+        if self.context.storage.count():
+            return 0, statement
+
+        return 1, statement

chatterbot/chatterbot.py

@@ -71,14 +71,6 @@ def get_response(self, input_text):
         if not plugin_response is False:
             return self.io.process_response(Statement(plugin_response))
 
-        # If no responses exist, return the input statement
-        if not self.storage.count():
-            self.storage.update(input_statement)
-            self.recent_statements.append(input_statement)
-
-            # Process the response output with the IO adapter
-            return self.io.process_response(input_statement)
-
         # Select a response to the input statement
         confidence, response = self.logic.process(input_statement)
 

tests/test_adaptation.py

@@ -14,10 +14,12 @@ def test_add_storage_adapter(self):
         self.assertEqual(len(self.adaptation.storage_adapters), 1)
 
     def test_add_logic_adapter(self):
+        count_before = len(self.adaptation.logic.adapters)
+
         self.adaptation.add_adapter(
             "chatterbot.adapters.logic.ClosestMatchAdapter"
         )
-        self.assertEqual(len(self.adaptation.logic.adapters), 1)
+        self.assertEqual(len(self.adaptation.logic.adapters), count_before + 1)
 
     def test_add_io_adapter(self):
         self.adaptation.add_adapter(