Outside-In vs Inside-Out (Proxies vs Adapters)

Question

Hi all,
can anybody tell me about outside-in and inside-out development approach?
What meaning have "outside" and "in" by outside-in? and "inside" and "out" by inside-out? I have read, that the first one are used by proxies, the second -  by adapters.
But I don't really know, how I should understand this "outside" and "inside"?

Answer 1

Hi,
just have a look at this quote:
You can use the following approaches when developing interfaces:
+·        Outside-In: You can develop new, platform-independent message interfaces by using the Integration Builder. Message interfaces are based on the WSDL standard Web Services Description Language), an XML schema for describing network services. Using this description, you can generate platform-specific proxies in Java or ABAP that you can then use to implement the actual message exchange.
·        Inside-Out: You can connect interfaces from SAP and non-SAP systems to SAP Exchange Infrastructure by using adapters. The Integration Builder can import interface descriptions in XML format for BAPI, RFC, and IDoc interfaces from SAP systems Release 4.0 or higher.+
from:
http://help.sap.com/saphelp_nw04/helpdata/en/ba/d4c23b95c8466ce10000000a114084/content.htm
basically it's all about where you start developing
your interfaces either in XI (and later one in the
system - by proxies ) or in system first and then you try to match
to this interface in XI (by importing IDOCs, RFC, external definitions etc.)
Regards,
michal
XI / PI FAQ - Frequently Asked Questions