Understanding COM+ and its Features: Transactions, Object Pooling, Queued Components, Slides of Computer Networks

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Windows 2000 Web and

Application Services

Presentation Overview

Introduction

Internet information services (IIS)

The component object model and COM+

Transaction service

Message queuing with MSMQ

Data access technology

Conclusion

Internet information services

(IIS)

HTTP 1.

Secure Sockets Layer

Common Gateway Interface (CGI)

Web Distributed Authoring Versioning

(WebDAV)

HTTP 1.1(Hypertext Transfer Protocol)

HTTP 1.1, that promises to bring Web pages a little

faster to your browser and reduce some of the Web's

enormous traffic. Developed by a committee of the

Internet Engineering Task Force (IETF) that includes the

Web's chief creator Tim Berners-Lee, HTTP 1.1 exists as

a "proposal," but in fact, most major Web servers and

browser clients are at some stage of supporting it.

Common Gateway Interface (CGI)

The common gateway interface (CGI) is a standard way

for a Web server to pass a Web user's request to an

application program and to receive data back to forward

to the user. When the user requests a Web page (for

example, by clicking on a highlighted word or entering a

Web site address), the server sends back the requested

page. However, when a user fills out a form on a Web

page and sends it in, it usually needs to be processed by

an application program. The Web server typically passes

the form information to a small application program that

processes the data and may send back a confirmation

message. This method or convention for passing data

back and forth between the server and the application is

called the common gateway interface (CGI). It is part of

the Web's Hypertext Transfer Protocol (HTTP).

Web Distributed Authoring Versioning WebDAV (World Wide Web Distributed Authoring and Versioning) is the Internet Engineering Task Force (IETF) standard for collaborative authoring on the Web: a set of extensions to the Hypertext Transfer Protocol (HTTP) that facilitates collaborative editing and file management between users located remotely from each other on the Internet. WebDAV is expected to have an impact on the development of virtual enterprises, by enabling remote groups to work together in new ways. For example, WebDAV- conforming tools could be used by a virtual organization to develop business plans, create software, or write libraries of information. The WebDAV work group is part of the applications section of the World Wide Web Consortium (W3C); their charter states its goal as to "define the HTTP extensions necessary to enable distributed Web authoring tools to be broadly interoperable, while supporting user needs." WebDAV is expected to fulfill early expectations of the Web's collaborative potential, by adding write access to the read access afforded by HTTP. WebDAV will enable users to collaborate over the Web in the same way as they might over a corporate intranet.

How COM work?

Customer Information Product Information Credit Information Shipping Information

The major features COM+

introduces are:

• integrated Transactions
• Object Pooling
• Queued Components
• COM+ Events

Object pooling

Object pooling is an automatic service provided by COM+ that lets application developers configure a component so that instances of it are kept active in a pool, ready to be used by any client that requests the component. Developers can administratively configure and monitor the pool maintained for a given component, specifying characteristics such as pool size and creation request timeout values. Once the application is running, COM+ manages the pool, handling the details of object activation and reuse according to pre-specified criteria.

Queued Components

The Queued Components feature takes advantage of Microsoft Message Queuing Services (MSMQ) to let server components logically participate in transactions while unavailable or offline. This allows standard COM components to use MSMQ to deliver asynchronous capabilities. While developers can use MSMQ to write applications that use the capabilities provided by queued components, such development is relatively labor-intensive. Programming with queued components is much faster, and does not require the developer to learn new techniques.

Transaction service

How transaction services work?

Data Customer Information Product Information Credit Information Shipping Information Web Server Shipping Server Credit Processing Server Product Inventory Server Customer Information Server Client Order Form

Data Customer Information Product Information Credit Information Shipping Information Web Server Shipping Server Credit Processing Server Product Inventory Server Customer Information Server Request and Response Queues Client Order Form

MSMQ Features

COM-based access

Integration with transactions

Automatic message journaling

Automatic notification

Built-in data integrity, data privacy, and digital signature

services

Message priority support

Simplified application integration

Network protocol independence