Context Object Pattern

Short Description
A Design Pattern for Efficient Information Sharing across Multiple System Layers. Arvind S. Krishna, Douglas C. Schmidt …

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Content
Context Object
A Design Pattern for Efficient Information Sharing across Multiple System Layers
Arvind S. Krishna, Douglas C. Schmidt
Electrical Engineering & Computer Science
Vanderbilt University, Nashville, TN
{arvindk, schmidt}@dre.vanderbilt.edu
Michael Stal
Siemens AG Corporate Technology
Munich, Germany
michael.stal@siemens.com
Abstract
Software systems with a layered architecture, such as mid-dleware, need to propagate/share information across the different system layers. In middleware for example, effi-cient information sharing across different middleware lay-ers enables timely processing of client requests; a critical middleware functionality This paper presents the Context Object pattern that allows efficient processing of requests by propagating context information between different mid-dleware layers. Using this pattern, a layer/session propa-gates per-request information required by the next layer/session in a context object, which eliminates the need for (1) per-request state within each layer and (2) lock-ing/synchronization to access per-request information across different layers. This pattern is used in CORBA Object Request Brokers (ORBs) for request processing.
1 Intent
This pattern provides an efficient, and application-transparent way of sharing information between different layers in a software system.
2 Example
Many applications use…