14.3 Integration of Components with Architecture

Many current technologies, including CORBA, DCOM (Distributed Component Object Model), and Java RMI (Remote Method Invocation), can provide a de facto standard for local and distributed object communication (Baker 1998; Mowbray and Ruh 1997; OMG 1999; Rine and Retnadhas 1980; Rine and Ahmed 1997; Trevor et al. 1994). For these tools to be useful, the component implementations must be prepared to conform to the de facto standard imposed by the environment. These technologies provide client/server communications. However, each of these uses different incompatible styles. This simple requirement may make functionally useful commercial products impossible to use in some chosen environment.

Because interaction code for a given environment is part of the component's implementation, moving it to a different environment involves making changes to source code; changing the source code for a commercial product is generally not an option. In addition, as software components move to new environments, the underlying network often changes. Different networks offer different types of reliability and quality of service (QoS), and are managed and controlled in different ways. This heterogeneity is a source of complexity for software architects and designers of distributed applications, especially as the variety of network types and QoS options increases.

Integration can be difficult when even considering a single runtime environment and a de facto standard interaction style such as client/server (Beach 1992; Meyer 1992; White and Purtilo 1992; White 1995), particularly in the context of reuse and maintenance (Rine and Chen 1996, 1998; Rine 1997, 1998). Many problems can arise: differences in parameter ordering, differences in data types, differences in the expected interaction mechanism, and differences in the meaning or semantics of the interfaces themselves. These differences can sometimes be fixed by adapting the component source code; however, this usually leads to multiple different versions of the same component and means that the new version of the component should be retested, negating one of the benefits of reuse.

In general solving the interface problems of software components involves the study of three dimensions:

The problems addressed in this research include the varying mismatches between the interfaces of different software components.

Network performance is characterized by various QoS parameters, such as bandwidth, reliability, and end-to-end delivery delay. Different networks offer different QoS service levels, such as best effort, controlled, and guaranteed (Zhang 1996). Best-effort service networks do not provide applications assurance that a particular QoS request will be satisfied, but rather are engineered to deliver the best possible performance. An example of a best-effort network is the current Internet, which at times experiences significant levels of congestion and poor performance. Controlled and guaranteed service networks provide assured performance levels through combinations of admission control tests, traffic-policing mechanisms and packet-scheduling policies. Examples of these types of networks include the future-generation Internet proposals (Bradshaw 1997) and some types of ATM networks (ATM 1996).

Distributed applications must use different service networks in different ways. In a best-effort network, an application simply sends data using network send primitives. In controlled and guaranteed architectures, the application must specify a variety of desired QoS parameters before data are sent (Bradshaw 1997; Zhang 1996). Further, because of admission control and QoS restrictions, the network itself may reject or seek to modify the request. In order for applications to take advantage of these options, the networks' semantic differences must be reflected back through to the distributed application (Ahlgren et al. 1998; Clark and Tennenhouse 1990). By moving this management complexity into interface adapters, components can take advantage of entirely different network architectures without needing to have their code modified.

An example of the need for this type of control arises from a distributed educational software and course presentation system (Pullen 1998). An instructor uses distributed instructional software for slide presentations and real-time annotations. A possible scenario is to connect to a remote classroom by a high-bandwidth guaranteed service network capable of transporting two-way audio and video. At the same time, a student may be participating from home over a slow modem connection and a student may have a wireless mobile laptop. These two students have sufficient network connectivity for audio and slide only presentations. Further, the underlying network architectures supporting the remote classroom, the at-home student, and the student with the wireless unit are completely different from each other. It is desirable to support all three types of network connectivity without having to change the instructional software. This is possible by placing communication control in the appropriate adapters. This technical approach is being used at George Mason University, using the NEW distance education tools kit invented by Pullen, to teach distributed/distance education information technology and engineering courses.

Top Title TOC Preface P.1 What Is XML? P.2 XML Concepts P.3 XML-Related Technologies P.4 XML Data Management P.5 How This Book Is Organized P.6 Who Should Read This Book P.7 Resources Acknowledgments Chapter 8 Chapter 12 Chapter 13 Chapter 14 Chapter 19 Part I: What Is XML? Chapter 1. Information Modeling with XML 1.1 Introduction 1.2 XML as an Information Domain 1.3 How XML Expresses Information 1.4 Patterns in XML 1.5 Common XML Information-Modeling Pitfalls 1.6 A Very Simple Way to Design XML 1.7 Conclusion Part II: Native XML Databases Chapter 2. Tamino-Software AG's Native XML Server 2.1 Introduction 2.2 Tamino Architecture and APIs 2.3 XML Storage 2.4 Querying XML 2.5 Tools 2.6 Full Database Functionality 2.7 Conclusion Chapter 3. eXist Native XML Database 3.1 Introduction 3.2 Features 3.3 System Architecture Overview 3.4 Getting Started 3.5 Query Language Extensions 3.6 Application Development 3.7 Technical Background 3.8 Conclusion Chapter 4. Embedded XML Databases 4.1 Introduction 4.2 A Primer on Embedded Databases 4.3 Embedded XML Databases 4.4 Building Applications for Embedded XML Databases 4.5 Conclusion Part III: XML and Relational Databases Chapter 5. IBM XML-Enabled Data Management Product Architecture & Technology 5.1 Introduction 5.2 Product and Technology Offering Summaries 5.3 Current Architecture and Technology 5.4 Future Architecture and Technology 5.5 Conclusion Notices Chapter 6. Supporting XML in Oracle9i 6.1 Introduction 6.2 Storing XML as CLOB 6.3 XMLType 6.4 Using XSU for Fine-Grained Storage 6.5 Building XML Documents from Relational Data 6.6 Web Access to the Database 6.7 Special Oracle Features 6.8 Conclusion Chapter 7. XML Support in Microsoft SQL Server 2000 7.1 Introduction 7.2 XML and Relational Data 7.3 XML Access to SQL Server 7.4 Serializing SQL Query Results into XML 7.5 Providing Relational Views over XML 7.6 SQLXML Templates 7.7 Providing XML Views over Relational Data 7.8 Conclusion Chapter 8. A Generic Architecture for Storing XML Documents in a Relational Database 8.1 Introduction 8.2 System Architecture 8.3 The Data Model 8.4 Creating the Database 8.5 Connecting to the Repository 8.6 Uploading XML Documents 8.7 Querying the Repository 8.8 Further Enhancements 8.9 Conclusion Chapter 9. An Object-Relational Approach to Building a High-Performance XML Repository 9.1 Introduction 9.2 Overview of XML Use-Case Scenario 9.3 High-Level System Architecture 9.4 Detailed Design Descriptions 9.5 Conclusion Part IV: Applications of XML Chapter 10. Knowledge Management in Bioinformatics 10.1 Introduction 10.2 A Brief Molecular Biology Background 10.3 Life Sciences Are Turning to XML to Model Their Information 10.4 A Genetic Information Model 10.5 NeoCore XMS* 10.6 Integration of BLAST into NeoCore XMS Conclusion Chapter 11. Case Studies of XML Used with IBM DB2 Universal Database 11.1 Introduction 11.2 Case Study 1: "Our Most Valued Customers Come First" 11.3 Case Study 2: "Improve Cash Flow" 11.4 Conclusion Notices Chapter 12. The Design and Implementation of an Engineering Data Management System Using XML and J2EE 12.1 Introduction 12.2 Background and Requirements 12.3 Overview 12.4 Design Choices 12.5 Future Directions 12.6 Conclusion Chapter 13. Geographical Data Interchange Using XML-Enabled Technology within the GIDB System 13.1 Introduction 13.2 GIDB METOC Data Integration 13.3 GIDB Web Map Service Implementation 13.4 GIDB GML Import and Export 13.5 Conclusion Chapter 14. Space Wide Web by Adapters in Distributed Systems Configuration from Reusable Components 14.1 Introduction 14.2 Advanced Concept Description: The Research Problem 14.3 Integration of Components with Architecture 14.4 Example 14.5 Future Generation NASA Institute for Advanced Concepts, Space Wide Web Research, and Boundaries 14.6 Advanced Concept Development 14.7 Conclusion Chapter 15. XML as a Unifying Framework for Inductive Databases 15.1 Introduction 15.2 Past Work 15.3 The Proposed Data Model: XDM 15.4 Benefits of XDM 15.5 Toward Flexible and Open Systems 15.6 Related Work 15.7 Conclusion Chapter 16. Designing and Managing an XML Warehouse 16.1 Introduction 16.2 Architecture 16.3 Data Warehouse Specification 16.4 Managing the Metadata 16.5 Storage and Management of the Data Warehouse 16.6 DAWAX: A Graphic Tool for the Specification and Management of a Data Warehouse 16.7 Related Work 16.8 Conclusion Part V: Performance and Benchmarks Chapter 17. XML Management System Benchmarks 17.1 Introduction 17.2 Benchmark Specification 17.3 Benchmark Data Set 17.4 Existing Benchmarks for XML 17.5 Conclusion Chapter 18. The Michigan Benchmark: A Micro-Benchmark for XML Query Performance Diagnostics 18.1 Introduction 18.2 Related Work 18.3 Benchmark Data Set 18.4 Benchmark Queries 18.5 Using the Benchmark 18.6 Conclusion Chapter 19. A Comparison of Database Approaches for Storing XML Documents 19.1 Introduction 19.2 Data Models for XML Documents 19.3 Databases for Storing XML Documents 19.4 Benchmarking Specification 19.5 Test Results 19.6 Related Work 19.7 Summary Chapter 20. Performance Analysis between an XML-Enabled Database and a Native XML Database 20.1 Introduction 20.2 Related Work 20.3 Methodology 20.4 Database Design 20.5 Discussion 20.6 Experiment Result 20.7 Conclusion Chapter 21. Conclusion References Contributors Editors Chapter 1: Information Modeling with XML Chapter 2: Tamino-Software AG's Native XML Server Chapter 3: eXist Native XML Database Chapter 4: Embedded XML Databases Chapter 5: IBM XML-Enabled Data Management Product Architecture and Technology Chapter 6: Supporting XML in Oracle9i Chapter 7: XML Support in Microsoft SQL Server 2000 Chapter 8: A Generic Architecture for Storing XML Documents in a Relational Database Chapter 9: An Object-Relational Approach to Building a High-Performance XML Repository Chapter 10: Knowledge Management in Bioinformatics Chapter 11: Case Studies of XML Used with IBM DB2 Universal Database Chapter 12: The Design and Implementation of an Engineering Data Management System Using XML and J2EE Chapter 13: Geographical Data Interchange Using XML-Enabled Technology within the GIDB System Chapter 14: Space Wide Web by Adapters in Distributed Systems Configuration from Reusable Components Chapter 15: XML as a Unifying Framework for Inductive Databases Chapter 16: Designing and Managing an XML Warehouse Chapter 17: XML Management System Benchmarks Chapter 18: The Michigan Benchmark: A Micro-Benchmark for XML Query Performance Diagnostics Chapter 19: A Comparison of Database Approaches for Storing XML Documents Chapter 20: Performance Analysis between an XML-Enabled Database and a Native XML Database Remember the name: eTutorials.org Copyright eTutorials.org 2008-2023. 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