D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....besides OORTSF and SESAG, there is practically no other work on enterprise application frameworks devoted to real time application development. As far as middleware integration frameworks for real time applications are concerned, there has been a TAO Real Time ORB proposed by Schmidt recently [18]. As far as software components are concerned, Stewart has recently proposed port based object models, framework process models, state variable table for inter process communication, and code generation for both Real Time Operating System (RTOS) and real time executive environments [19] All of ....

D. Schmidt, "Applying design patterns and frameworks to develop object-oriented communication software," Handbook of Programming Languages, Vol. I, 1997.

....to achieve reuse. Patterns aid the development of reusable software components and frameworks by expressing the structure and collaboration of participants in a software architecture at a level higher than source code or object oriented design models that focus on individual objects and classes [31]. Patterns also are particularly useful for documenting software architectures and design abstractions. They provide a common and concise vocabulary which is useful in conveying the purpose of a given software design. The Onyx simulation environment is designed to be both multi tiered and ....

SCHMIDT, D. C., "Applying Design Patterns and Frameworks to Develop Object-Oriented Communications Software," Handbook of Programming Languages, Volume I, P. Salus, ed., MacMillian Computer Publishing, 1997.

....static and dynamic configurations according to environmental factors, such as workload characteristics, support for kernel level threading and asynchronous I O in the operating system, and number of CPUs. The JAWS structure is implemented using components of the ACE [3] framework. Many patterns [4, 5] have been used to establish collaborations between JAWS and ACE components. JAWS components implement the following adaptive strategies: 1) Concurrency Strategy defines a concurrency policy for executing the JAWS HTTP protocol. Two models are present in the current version: thread per request ....

D. Schmidt. "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software", in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....can be classified by their position in the software development process. Infrastructure frameworks. These frameworks aim to simplify the software development process. Examples include frameworks for operating systems [CampbellIslam 1993] debuggers [Bruegge et al. 1993] communication tasks [Schmidt, 1997], and user interface design [Weinand et al. 1988] System infrastructure frameworks are used internally within a software project and are usually not delivered to a client. Middleware frameworks. These frameworks are used to integrate existing distributed applications and components. Common ....

D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," Handbook of Programming Languages, Volume I, edited by Peter Object Design Page 299 Tuesday, July 13, 1999 12:21 PM 300 Chapter 7 . Object Design Salus, MacMillan Computer Publishing, 1997.

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D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

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D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....event dispatching strategies to be customized in accordance with key environmental factors. These factors include traffic patterns, workload characteristics, support for kernel level threading and or asynchronous I O in the OS, and the number of available CPUs. JAWS is structured as a framework [18] that contains the following components: an Event Dispatcher, Concurrency Strategy, I O Strategy, Protocol Pipeline, Protocol Handlers, and Cached Virtual Filesystem. Each component is structured as a set of collaborating objects implemented with the ACE C communication framework [16] Each ....

Douglas C. Schmidt. Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software. In Peter Salus, editor, Handbook of Programming Languages. MacMillan Computer Publishing, 1997.

....realtime and embedded (DRE) applications using standards based COTS middleware. The optimizations and framework extensions described in this paper will be integrated first into the TAO Event Service [7] and the Kokyu source code will be available as a distinct framework provided with the ACE [27] and TAO distributions. Our future work will focus on (1) a more thorough analysis of the space of scheduling heuristics enabled by this approach, combining aprioriobservations and empirical measurements to offer specific patterns and overall design guidance to developers of DRE systems and (2) ....

D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997. 12

....error prone, and non portable aspects of developing and maintaining distributed applications via low level network programming mechanisms, such as sockets. Widelyused examples of infrastructure middleware include Java virtual machines (JVMs) and the ADAPTIVE Communication Environment (ACE) [2]. # Distribution middleware: This layer builds upon lower level infrastructure middleware and allows clients to invoke operations on distributed objects without concern for object location, programming language, OS platform, communication protocols and interconnects, and hardware [3] At the ....

....and mechanisms should be placed in the proper strategic context within a broader software architecture. 2. Effective reuse: They amortize software life cycle effort by leveraging previous development expertise and reifying implementations of key patterns [4, 5] into reusable middleware frameworks [2]. Most distributed applications in the future will be built by integrating and scripting domain specific and common pluggable middleware service components, rather than being programmed entirely from scratch. 3. Open standards: They provide a standard [3] set of software components that help to ....

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D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....buffering optimization to avoid data copying across endsystem layers. In addition, TAO runs on conventional real time interconnects, such as VME backplanes and multi processor shared memory environments, as well as TCP IP. TAO internals: TAO is developed using lower level middleware called ACE [28], which implements core concurrency and distribution patterns [8] for communication software. ACE provides reusable C wrapper facades and framework components that support the QoS requirements of highperformance, real time applications and higher level middleware like TAO. ACE and TAO run on a ....

....and middleware architectures. The primary reason is that many conventional ORBs are configured statically at compile time and link time by ORB developers, rather than dynamically at installation time or run time by application developers. Statically configured ORBs have the following drawbacks [28]: Inflexibility: Statically configured ORBs tightly couple each component s implementation with the configuration of internal ORB components, i.e. which components work together and how they work together. As a result, extending statically configured ORBs requires modifications to existing ....

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D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....processing the event, a leader thread can select any follower thread to wait on the leader s event source. A drawback with this variant, however, is that the number of participating thread must always be greater than the number of event sources. 11 Known Uses ACE Thread Pool Reactor framework [18]. The ACE framework provides an object oriented framework implementation of the Leader Followers pattern called the thread pool reactor (ACE TP Reactor) to demultiplex events to event handlers within a pool of threads. When using a thread pool reactor, an application pre spawns a fixed number of ....

D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....in a configuration script. Adding a new parameter to represent the list of protocols is straightforward, i.e. the default registry simply examines this list and links the services into the address space of the application, using the Component Configurator pattern implementation provided by ACE [29]. 5 Figure 8 depicts the Connector Registry and its relation to the ACE Component Configurator implementation. 4.3 Profile Creation Context: The contents of a profile must be parsed to determine an object s location. In general, the format and semantics 5 ACE provides a rich set of reusable ....

....run on platforms that do not support native C exceptions, however. Therefore, it is already necessary to check return values, so there is no additional burden on TAO developers. 4. 6 Adapting TAO to the ACE Framework Context: TAO is built largely using the reusable and portable ACE framework [29] components, particularly Reactors, Acceptors, Connectors, Service Handlers, and ACE IPC wrapper facades [29] TAO s pluggable protocols framework uses inheritance and dynamic binding to configure these ACE components to create new protocols. Problem: Using the lower level ACE IPC wrapper facade ....

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D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....implements these patterns. Recognizing the patterns that commonly occur in many communication software systems helped shape the development of reusable framework components. The gateway systems this paper is based upon were implemented using the ADAPTIVE Communication Environment (ACE) framework [9], which provides integrated reusable C wrapper facades and components that perform common communication software tasks. These tasks include event demultiplexing, event handler dispatching, connection establishment, routing, dynamic configuration of application services, and concurrency control. ....

....formats and the gateway s routing protocol. The behavior of the application independent components in the gateway is outlined below: Interprocess communication (IPC) components: The SOCK Stream, SOCK Connector,andSOCK Acceptor components encapsulate the socket network programming interface [9]. These components are implemented using the Wrapper Facade pattern [1] which simplifies the development of portable communication software by shielding developers from low level, tedious, and error prone socket level programming. In addition, they form the foundation for higher level patterns ....

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D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....pieces together. This paper focuses on the patterns and framework components used to develop a high performance Web server called JAWS [1, 3] JAWS is both a Web server and a framework from which other types of servers can be built. The JAWS framework itself was developed using the ACE framework [6, 7]. The ACE framework reifies key patterns [5] in the domain of communication software. The framework and patterns in JAWS and ACE are representative of solutions that have been applied successfully to communication systems ranging from telecommunication system management [8] to enterprise medical ....

D. C. Schmidt, "Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software," in Handbook of Programming Languages (P. Salus, ed.), MacMillan Computer Publishing, 1997.

....to allow these Web server strategies to be customized according to key environmental factors. These factors include traffic patterns, workload characteristics, support for kernel level threading and or asynchronous I O in the OS, and the number of available CPUs. JAWS is structured as a framework [22] that contains the following components: an Event Dispatcher, Concurrency Strategy, I O Strategy, Protocol Pipeline, Protocol Handlers, Cached Virtual Filesystem, and Tilde Expander. Each component is structured as a set of collaborating objects implemented with the ADAPTIVE Communication ....

Douglas C. Schmidt. Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software. In Peter Salus, editor, Handbook of Programming Languages. MacMillan Computer Publishing, 1997.

....to allow these Web server strategies to be customized according to key environmental factors. These factors include traffic patterns, workload characteristics, support for kernel level threading and or asynchronous I O in the OS, and the number of available CPUs. JAWS is structured as a framework [16] that contains the following components: an Event Dispatcher, Concurrency Strategy, I O Strategy, Protocol Pipeline, Protocol Handlers, Cached Virtual Filesystem, and Tilde Expander. Each component is structured as a set of collaborating objects implemented with the ADAPTIVE Communication ....

Douglas C. Schmidt. Applying Design Patterns and Frameworks to Develop Object-Oriented Communication Software. In Peter Salus, editor, Handbook of Programming Languages. MacMillan Computer Publishing, 1997.

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