Chapter 17 -- Using Server Components

Chapter 17

In this section of the book, we'll be covering how to develop n-tier architectures using Microsoft Visual InterDev 6.0 and other products in the Microsoft Visual Studio 6.0 and Microsoft BackOffice Server 4.0 product suite. Over the next six chapters, we'll take a look at:

  • The prebuilt, server-side components available in the Visual InterDev Toolbox
  • How to use Microsoft Visual Basic 6.0 to construct your own server-side components
  • How to work with transactional Active Server Pages (ASP) Web pages
  • How to use Visual Basic 6.0 to construct transactional server-side components
  • How to use Microsoft Message Queue (MSMQ) within your Web applications

Of course, we'll also be taking a look at how to use Microsoft Transaction Server (MTS) for managing the transactional components that we create with Visual Basic 6.0.

We'll start off this section by covering some of the basics regarding Microsoft's framework for the development of n-tier applications. When we say "building n-tier applications," we really mean creating distributed, component-based applications that extend the scalability, performance, security, reliability, manageability, and maintainability of personal computer_based client/server and Internet applications. As Microsoft Windows NT makes significant advances into enterprise computing and is used as a strategic platform for business-critical applications, these types of architecture become increasingly important. This distributed computing architecture also enables Microsoft technologies to compete effectively. Of course, in the rapidly moving business and technology landscape, the products that deliver the simplest approach, the fastest results, the best interoperability and integration, and the lowest total cost of ownership often win. It's far more productive for developers to be able to concentrate on the business specifics of their applications than to have to become systems integrators and learn the complexities of object models and the like. Microsoft development tools and products do an excellent job of shielding developers from these types of complexities so that they can concentrate on what's important—delivering timely and highly functional applications to support their organizations' business objectives.

One advantage of an n-tier architecture is that the business logic is separated from the presentation layer. This simplifies application maintenance because business rules can be changed more easily without having to rework the presentation layer. It also means that business rules are encapsulated within server-side components instead of being scattered (often redundantly) throughout the presentation layer. By moving the business rules to a middle tier, they can also be reused across multiple applications and often across multiple delivery channels, including browser, personal computer, hand-held PC, WebTV, kiosk, and others.

Windows DNA

Windows Distributed interNet Applications Architecture (Windows DNA) is Microsoft's framework for building a new generation of computing solutions that brings together personal computing and the Internet. This framework is the basis for Microsoft's Web architecture for the next three to five years. Microsoft is delivering on this framework in three phases over this time frame. The first phase is available now in products such as Visual Studio 6.0, Windows NT 4.0 Server and Workstation, Microsoft Internet Information Server (IIS) 4.0, and Microsoft Internet Explorer 4.0. Windows NT 5.0 and then COM+ will take developers and end users into the next generation of Windows DNA by making it even easier to create and manage distributed applications.

These guiding principles outline the goal of Windows DNA:

  • Web computing without compromise
  • Interoperability
  • True integration
  • Lower cost of ownership
  • Faster time to market

Once again, these principles make sound business sense. Developers are empowered to focus their efforts on delivering applications without worrying about the system integration aspects.

Windows DNA is comprised of a standard set of Microsoft Windows-based services that support user interface and navigation, business processes, and data storage. These services are distributed application services, distributed infrastructure services, and common interfaces. Table 17-1 shows the services supported by Windows DNA and the product mappings.

Table 17-1. Windows DNA services and product mappings.

Service Interface Product Mapping
Application services
Web server HTML Internet Information Server (IIS)
Web browser HTML Internet Explorer
Scripting VBScript, JScript™ "Denali," Dynamic HTML
Transaction service OLE Transactions MTS
Message queuing service "Falcon" API MMQS
Database ODBC, OLE DB Microsoft SQL Server
Mail and collaboration Server MAPI, POP3 Microsoft Outlook, Microsoft Exchange
Java virtual machine Java Microsoft Java virtual machine
Universal data access ADO, OLE DB, ODBC Various
Infrastructure services
Directory ADSI Active Directory, Windows NT Server
Security SSL Windows NT Server, Internet Explorer
Network TCP/IP, pipes, WinSock, etc. Windows family
Remote file and print CIFS, SMB Windows family
Components COM, DCOM, Microsoft ActiveX Windows family

Figure 17-1 shows the Windows DNA services and how they fit in with COM.

click to view at full size.

Figure 17-1. Windows DNA services.

Windows DNA's support for legacy integration allows organizations to leverage existing infrastructure investments. Microsoft's Cedar technology allows bidirectional access to transaction systems such as CICS, as well as legacy data sources, including DB2/MVS, IMS, and VSAM. Cedar also enables legacy applications to be Web-enabled via IIS. Visual InterDev developers can therefore create Web applications that can truly reach into the organization and pull out data wherever it may reside.

COM+

COM+ will arrive in the third phase of the Windows DNA evolution. COM+ makes it even easier for developers to build and reuse components. It preserves the investments in code and skill sets that organizations have made in COM, and places more of the infrastructure into the system. Thus developers can concentrate on higher-level business functionality rather than the low-level services to support that functionality.

COM+ defines a simpler and more robust model for registering, installing, and versioning components than its predecessor. It also introduces a new extensibility mechanism called "interception." Interceptors can receive and process events related to instance creation, calls and returns, errors, and instance deletion.

You can expect to hear a lot more about COM+ in the coming months as Windows DNA evolves.



Programming Microsoft Visual InterDev 6. 0
Programming Microsoft Visual InterDev 6.0
ISBN: 1572318147
EAN: 2147483647
Year: 2005
Pages: 143

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