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--- how_do_i_code_recursive_system_operations_in_dci [2014/01/20 00:29]
gazoot created
+++ how_do_i_code_recursive_system_operations_in_dci [2014/12/05 14:04] (current)
jcoplien
@@ Line 1: / Line 1: @@
 ====== How do I code recursive system operations in DCI? ======
-There is nothing special about recursion in DCI; it can be done where it's deemed useful.
+There is nothing special about recursion in general in DCI, it can be done where it's deemed useful. It's important to remember however, that [[can_a_role_be_played_by_several_different_objects_in_a_given_context_instantiation|Roles cannot be rebound during a System operation]] and its following Interaction.
+If you do a recursion on a whole System operation though, it's common that you want to rebind Roles at the recursion point. There are a few ways of doing that:
+  - Instantiate another Context at the recursion point, and call its System Operation
+  - Call the atomic "Bind Roles" method right before calling the System Operation again.
+The choice is implementation- and convention-based. If you bind Roles only in the constructor, the first option could be more convenient.
+Multiple calls to the "Bind Roles" method may not be a good idea. See: [[Can I rebind roles to objects multiple times over the lifetime of a Context object?|Can I rebind roles to objects multiple times over the lifetime of a Context object?]]

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