Added on_registered() callback to CommandSet

3 files changed, 15 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5c65bb8a..a22bfdf8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 1.3.9 (September 01, 2020)
+* Enhancements
+    * Added `on_registered()` callback to `CommandSet` class. This is called by `cmd2.Cmd` after a
+    `CommandSet` is registered and all its commands have been added to the CLI.
+
 ## 1.3.8 (August 28, 2020)
 * Bug Fixes
     * Fixed issue where subcommand added with `@as_subcommand_to` decorator did not display help
diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index d768085a..8fd3d243 100644
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -503,6 +503,7 @@ class Cmd(cmd.Cmd):
             self._installed_command_sets.append(cmdset)
 
             self._register_subcommands(cmdset)
+            cmdset.on_registered()
         except Exception:
             for attrib in installed_attributes:
                 delattr(self, attrib)
diff --git a/cmd2/command_definition.py b/cmd2/command_definition.py
index 27a044bc..3c663054 100644
--- a/cmd2/command_definition.py
+++ b/cmd2/command_definition.py
@@ -53,7 +53,7 @@ class CommandSet(object):
     def __init__(self):
         self._cmd = None  # type: Optional[cmd2.Cmd]
 
-    def on_register(self, cmd):
+    def on_register(self, cmd) -> None:
         """
         Called by cmd2.Cmd when a CommandSet is registered. Subclasses can override this
         to perform an initialization requiring access to the Cmd object.
@@ -66,7 +66,14 @@ class CommandSet(object):
         else:
             raise CommandSetRegistrationError('This CommandSet has already been registered')
 
-    def on_unregister(self):
+    def on_registered(self) -> None:
+        """
+        Called by cmd2.Cmd after a CommandSet is registered and all its commands have been added
+        to the CLI. Subclasses can override this to perform custom steps.
+        """
+        pass
+
+    def on_unregister(self) -> None:
         """
         Called by ``cmd2.Cmd`` when a CommandSet is unregistered and removed.