Overview

Building scalable distributed systems that efficiently perform enterprise-critical functions is incredibly challenging. Microsoft developed COM+ to help. COM+ is a sophisticated runtime environment for COM components. It is designed to make the development of scalable systems easier and is the foundation for higher-level frameworks such as BizTalk and Site Server Commerce Edition. But you cant use COM+ effectively if you dont understand how it works. Transactional COM+ explains how COM+ works and shows readers how to use the technology to its fullest potential as a framework for developing scalable applications. It examines the theory behind COM+, including the nature of scalability, why traditional object-oriented models are inappropriate for scalable systems, and the importance of transactions. The book explores how the two basic atoms of context and causality are used to implement COM+ runtime services. It introduces apartments and activities and the role they play in controlling concurrency in a COM+ process. It also introduces transaction streams and explains how they are used to integrate objects and transactions. Ewald shows how just-in-time activation and object pooling together change the relationship between a client and an object and reveals the importance of HTTP and MSMQ as communication protocols that offer significant advantages over DCOM. Most important, the author explains the influence all these factors have on the design of scalable COM+-based systems. Practical in its approach, Transactional COM+ goes beyond the rationale behind the technology and the details of its implementation to present concrete guidelines for using COM+ to build applications that scale.

Full Product Details

Author:   Tim Ewald
Publisher:   Pearson Education (US)
Imprint:   Addison Wesley
Dimensions:   Width: 18.60cm , Height: 2.90cm , Length: 23.30cm
Weight:   0.910kg
ISBN:  

9780201615944

ISBN 10:   0201615940
Pages:   464
Publication Date:   14 March 2001
Audience:   College/higher education ,  Tertiary & Higher Education
Format:   Paperback
Publisher's Status:   Out of Print
Availability:   Out of stock  

Table of Contents

1. Scalability. Scalability Basics. Identity. Identity in COM. Sharing Identities. Implementing Named Objects. The Problem with Sharing COM Objects. Identity Revisited. Implementing Named Objects with Key-Based Logical Identity. Implementing Named Objects on Top of a Database. What Has Been Gained? The Object-per-Client Model. Transactions. Enter Transactions. Clients and TMs and RMs, Oh My! Local Transactions and Distributed Transactions. The Transactions and Scalability Paradox. Integrating Objects and Transactions. Using Transactions Explicitly. Using Transactions Implicitly. Applying Transactions. Thinking about Roundtrips. A Complex Problem. A Possible Solution. A Much Better Solution. Thinking about Roundtrips Again. Processor Objects. Summary. 2. Atoms. The Linker Switch Story. An Experiment. The Windows Process Loader. How COM+ Works. From Consoles to Contexts. Cross-Context Calls. Contexts as Objects. Object Context Interfaces. Using Object Context. Where Do Contexts Come From? The Catalog. Applications. Libraries and Servers. Why Library Applications? Configured Classes. Custom Attributes. Changing the Contents of the Catalog. Context Flow. Causality. How Causality Works. Causalities as Objects. Call Context Interfaces. Using Call Context. Summary. 3. Mechanics. Context Relativity. The Problem. Marshaling Interface Pointers. The Global Interface Table. Context Relativity in Day-to-Day Life. The Cost of Contexts. A Context for Every Object. The Cost of Contexts in Time. The Cost of Contexts in Space. Are Contexts Worth the Price? Limiting Context. Nonconfigured Classes. Raw-Configured Classes. Context-Aware Code Revisited. A Different Way of Looking at the World. Subtle Complexities. Custom Marshaling. Some Other Observations. Summary. 4. Threads. Apartments. Apartment Types. Where Do Apartments Come From? Threading Models. Default Contexts. Remote Object Creation. Cross-Apartment Calls. STA Complexities. Cross-Apartment Call Overhead. Apartment Guidelines. Raw-Configured Classes Revisited. Activities. Enter Activities. Where Do Activities Come From? Detecting the Presence of an Activity. Allocating STA Objects to Apartments. Serializing Calls. Activity Reentrancy. Activity Deadlock. Activity Guidelines. Summary. 5. Objects. Object Pooling. Enabling Object Pooling. Reusing Objects. Controlling the Size of a Class's Pool. Implementing Pooled Classes. Accessing Context. Managing Resources. The GIT Trick (and Why It Doesn't Work). An Exception to the Rules. Object Pooling Guidelines. Just-in-Time Activation. Enabling JITA. How JITA Works. Flipping the Done Bit. The AutoComplete Attribute. JITA Notifications. JITA Guidelines. Lies, Damn Lies, and Statistics. Summary. 6. Transactions. Local Transactions. OLE DB. Higher Level APIs. Distributed Transactions. Enter the Distributed Transaction Coordinator. Starting a Distributed Transaction. Enlisting a Connection. The Two-Phase Commit Protocol. Distributed Transaction Complexities. Distributed Transaction Propagation. Connection Management. A Race Condition. Declarative Transactions. Transactional Objects. Enter Transaction Streams. Where Do Transaction Streams Come From? Detecting the Presence of a Transaction Stream. Creating and Propagating a Distributed Transaction. Autoenlisting Connections. Controlling a Declarative Transaction's Outcome. Flipping the Happy Bit. The Four Possible States of a Transactional Object. Root Objects and HRESULTs. Transaction Stream Caveats. Transaction Guidelines. Summary. 7. Isolation. Correctness versus Performance. Five Degrees of Isolation. Implementing Isolation Using Locks. Implementing Isolation Using Versions. Choosing an Isolation Level. Isolation-Level Guidelines. Specifying Isolation Levels. Isolation Levels and OLE DB. Isolation Levels and the DTC. Isolation Levels and COM+. Bring Your Own Transaction. ISOFLAGs. Deadlocks. Avoiding Deadlocks. Detecting Deadlocks. Timeouts and the DTC. Timeouts and COM+. Timeouts and OLE DB. Application-Level Isolation. Optimistic Application-Level Locking. Pessimistic Application-Level Locking. Summary. 8. Protocols. HTTP. HTTP Messages. HTTP Connection Management. Internet Information Server. Mapping Requests to Files. Mapping Requests to Processes. Mapping Requests to Contexts and Apartments. Processing Requests in Parallel. Active Server Pages. Processing ASP Requests. Transactional Pages. Transaction Outcome Notifications. Server.Execute and Server.Transfer. ASP Pages and Raw-Configured Classes. ASP Pages and Object Context. HTTP + XML = RPC. SOAP Messages. SOAP and HTTP. Applying SOAP. Message Queuing. Transactional Messaging. Applying Message Queuing. Summary. 9. Design. Machines, Processes, and Protocols. Machine Architecture. Process Architecture. Protocols. Processors and Helpers. A Simple Logical Model. A Simple Physical Model. Accessing Processors via HTTP. Transactions and Data Access. Accessing Data Efficiently. Middle-Tier State. Some Final Advice. Appendix A: Toward .NET. Appendix B: Building a Better Connection Pool. An Example. IObjectConstruct. IObjectControl. IConn. Using a Pooled Connection. Source Code. Appendix C: Debugging. Appendix D: Catalog Attributes and Component Services Explorer Property Pages. Application Property Pages. Class Property Pages. Interface Property Pages. Method Property Pages. Rules. Summary. Index. 0201615940T04062001

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Author Information

Tim Ewald is a Director of Content at DevelopMentor, a premier developer services company. His research and development work focuses on the design and implementation of scalable systems using component technologies such as COM and Java. Tim has authored or co-authored several DevelopMentor courses, including the MTS and COM+ curriculum. He is also a co-author of Effective COM (Addison-Wesley), a former columnist for DOC and Application Strategies, and a frequent conference speaker. Before joining DevelopMentor, Tim worked as an independent consultant specializing in COM and related technologies. 0201615940AB04062001

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