Enterprise Integration Patterns Designing, Building, and Deploying Messaging Solutions

by Hohpe, Gregor; Woolf, Bobby

• ISBN13: 9780321200686
• ISBN10: 0321200683
• Edition: 1st
• Format: Hardcover
• Copyright: 2003-10-10
• Publisher: Addison-Wesley Professional

Summary

bull;Would you like to use a consistent visual notation for drawing integration solutions? Look inside the front cover. bull;Do you want to harness the power of asynchronous systems without getting caught in the pitfalls? See "Thinking Asynchronously" in the Introduction. bull;Do you want to know which style of application integration is best for your purposes? See Chapter 2, Integration Styles. bull;Do you want to learn techniques for processing messages concurrently? See Chapter 10, Competing Consumers and Message Dispatcher. bull;Do you want to learn how you can track asynchronous messages as they flow across distributed systems? See Chapter 11, Message History and Message Store. bull;Do you want to understand how a system designed using integration patterns can be implemented using Java Web services, .NET message queuing, and a TIBCO-based publish-subscribe architecture? See Chapter 9, Interlude: Composed Messaging. Utilizing years of practical experience, seasoned experts Gregor Hohpe and Bobby Woolf show how asynchronous messaging has proven to be the best strategy for enterprise integration success. However, building and deploying messaging solutions presents a number of problems for developers. Enterprise Integration Patterns provides an invaluable catalog of sixty-five patterns, with real-world solutions that demonstrate the formidable of messaging and help you to design effective messaging solutions for your enterprise. The authors also include examples covering a variety of different integration technologies, such as JMS, MSMQ, TIBCO ActiveEnterprise, Microsoft BizTalk, SOAP, and XSL. A case study describing a bond trading system illustrates the patterns in practice, and the book offers a look at emerging standards, as well as insights into what the future of enterprise integration might hold. This book provides a consistent vocabulary and visual notation framework to describe large-scale integration solutions across many technologies. It also explores in detail the advantages and limitations of asynchronous messaging architectures. The authors present practical advice on designing code that connects an application to a messaging system, and provide extensive information to help you determine when to send a message, how to route it to the proper destination, and how to monitor the health of a messaging system. If you want to know how to manage, monitor, and maintain a messaging system once it is in use, get this book. 0321200683B09122003

Author Biography

Gregor Hohpe leads the enterprise integration practice at ThoughtWorks, Inc., a specialized provider of application development and integration services. Drawing from his extensive experience designing and implementing integration solutions for enterprise clients, Gregor has published a number of papers and articles presenting a no-hype view on enterprise integration, Web services, and Service-Oriented Architectures. He is a frequent speaker at technical conferences around the world.

Bobby Woolf is coauthor of The Design Patterns Smalltalk Companion (Addison-Wesley, 1998), and author of articles in IBM DeveloperWorks, Java Developer's Journal, and elsewhere. He has been a tutorial presenter at OOPSLA, JavaEdge, and Smalltalk Solutions, among other conferences.

0321200683AB09122003

Table of Contents

Foreword by John Crupi	xv
Foreword by Martin Fowler	xvii
Preface	xix
Acknowledgments	xxv
Introduction	xxix
Chapter 1: Solving Integration Problems Using Patterns	1	(38)
The Need for Integration	1	(1)
Integration Challenges	2	(2)
How Integration Patterns Can Help	4	(1)
The Wide World of Integration	5	(4)
Loose Coupling	9	(2)
One-Minute EAI	11	(4)
A Loosely Coupled Integration Solution	15	(2)
Widgets & Gadgets 'R Us: An Example	17	(20)
Internal Systems	18	(1)
Taking Orders	18	(2)
Processing Orders	20	(6)
Checking Status	26	(4)
Change Address	30	(2)
New Catalog	32	(1)
Announcements	33	(1)
Testing and Monitoring	34	(3)
Summary	37	(2)
Chapter 2: Integration Styles	39	(18)
Introduction	39	(4)
File Transfer (by Martin Fowler)	43	(4)
Shared Database (by Martin Fowler)	47	(3)
Remote Procedure Invocation (by Martin Fowler)	50	(3)
Messaging	53	(4)
Chapter 3: Messaging Systems	57	(42)
Introduction	57	(3)
Message Channel	60	(6)
Message	66	(4)
Pipes and Filters	70	(8)
Message Router	78	(7)
Message Translator	85	(10)
Message Endpoint	95	(4)
Chapter 4: Messaging Channels	99	(44)
Introduction	99	(4)
Point-to-Point Channel	103	(3)
Publish-Subscribe Channel	106	(5)
Datatype Channel	111	(4)
Invalid Message Channel	115	(4)
Dead Letter Channel	119	(3)
Guaranteed Delivery	122	(5)
Channel Adapter	127	(6)
Messaging Bridge	133	(4)
Message Bus	137	(6)
Chapter 5: Message Construction	143	(40)
Introduction	143	(2)
Command Message	145	(2)
Document Message	147	(4)
Event Message	151	(3)
Request-Reply	154	(5)
Return Address	159	(4)
Correlation Identifier	163	(7)
Message Sequence	170	(6)
Message Expiration	176	(4)
Format Indicator	180	(3)
Chapter 6: Interlude: Simple Messaging	183	(42)
Introduction	183	(4)
Request-Reply Example	183	(2)
Publish-Subscribe Example	185	(2)
JMS Request-Reply Example	187	(11)
Request-Reply Example	187	(2)
Request-Reply Code	189	(7)
Invalid Message Example	196	(1)
Conclusions	197	(1)
.NET Request-Reply Example	198	(9)
Request-Reply Example	198	(2)
Request-Reply Code	200	(5)
Invalid Message Example	205	(1)
Conclusions	206	(1)
JMS Publish-Subscribe Example	207	(18)
The Observer Pattern	207	(1)
Distributed Observer	208	(1)
Publish-Subscribe	209	(3)
Comparisons	212	(1)
Push and Pull Models	213	(6)
Channel Design	219	(3)
Conclusions	222	(3)
Chapter 7: Message Routing	225	(102)
Introduction	225	(5)
Content-Based Router	230	(7)
Message Filter	237	(6)
Dynamic Router	243	(6)
Recipient List	249	(10)
Splitter	259	(9)
Aggregator	268	(15)
Resequencer	283	(11)
Composed Message Processor	294	(3)
Scatter-Gather	297	(4)
Routing Slip	301	(11)
Process Manager	312	(10)
Message Broker	322	(5)
Chapter 8: Message Transformation	327	(34)
Introduction	327	(3)
Envelope Wrapper	330	(6)
Content Enricher	336	(6)
Content Filter	342	(4)
Claim Check	346	(6)
Normalizes	352	(3)
Canonical Data Model	355	(6)
Chapter 9: Interlude: Composed Messaging	361	(102)
Loan Broker Example	361	(10)
Obtaining a Loan Quote	361	(1)
Designing the Message Flow	362	(2)
Sequencing: Synchronous versus Asynchronous	364	(2)
Addressing: Distribution versus Auction	366	(2)
Aggregating Strategies: Multiple Channels versus Single Channel	368	(1)
Managing Concurrency	368	(1)
Three Implementations	369	(2)
Synchronous Implementation Using Web Services (by Conrad F D'Cruz)	371	(30)
Solution Architecture	371	(1)
Web Services Design Considerations	372	(4)
Apache Axis	376	(3)
Service Discovery	379	(1)
The Loan Broker Application	379	(2)
Components of the Loan Broker Application	381	(15)
Client Application	396	(1)
Running the Solution	397	(2)
Performance Limitations	399	(1)
Limitations of This Example	400	(1)
Summary	400	(1)
Asynchronous Implementation with MSMQ	401	(44)
Loan Broker. Ecosystem	401	(1)
Laying the Groundwork: A Messaging Gateway	402	(3)
Base Classes for Common Functionality	405	(5)
Designing the Bank	410	(2)
Designing the Credit Bureau	412	(1)
Designing the Loan Broker	413	(18)
Refactoring the Loan Broker	431	(4)
Putting it All Together	435	(1)
Improving Performance	435	(5)
A Few Words on Testing	440	(3)
Limitations of This Example	443	(1)
Summary	444	(1)
Asynchronous Implementation with TIBCO ActiveEnterprise (by Michael J. Rettig)	445	(18)
Solution Architecture	445	(3)
The Implementation Toolset	448	(3)
The Interfaces	451	(1)
Implementing the Synchronous Services	452	(3)
The Loan Broker Process	455	(4)
Managing Concurrent Auctions	459	(1)
Execution	460	(2)
Conclusions	462	(1)
Chapter 10: Messaging Endpoints	463	(74)
Introduction	463	(5)
Messaging Gateway	468	(9)
Messaging Mapper	477	(7)
Transactional Client	484	(10)
Polling Consumer	494	(4)
Event-Driven Consumer	498	(4)
Competing Consumers	502	(6)
Message Dispatcher	508	(7)
Selective Consumer	515	(7)
Durable Subscriber	522	(6)
Idempotent Receiver	528	(4)
Service Activator	532	(5)
Chapter 11: System Management	537	(40)
Introduction	537	(3)
Control Bus	540	(5)
Detour	545	(2)
Wire Tap	547	(4)
Message History	551	(4)
Message Store	555	(3)
Smart Proxy	558	(11)
Test Message	569	(3)
Channel Purger	572	(5)
Chapter 12: Interlude: System Management Example	577	(26)
Loan Broker System Management	577	(26)
Instrumenting the Loan Broker	578	(1)
Management Console	579	(1)
Loan Broker Quality of Service	579	(8)
Verify the Credit Bureau Operation	587	(5)
Credit Bureau Failover	592	(3)
Enhancing the Management Console	595	(7)
Limitations of This Example	602	(1)
Chapter 13: Integration Patterns in Practice	603	(22)
Case Study: Bond Pricing System (by Jonathan Simon)	603	(22)
Building a System	603	(1)
Architecture with Patterns	604	(6)
Structuring Channels	610	(4)
Selecting a Message Channel	614	(4)
Problem Solving with Patterns	618	(1)
Flashing Market Data Updates	618	(2)
Major Production Crash	620	(3)
Summary	623	(2)
Chapter 14: Concluding Remarks	625	(24)
Emerging Standards and Futures in Enterprise Integration (by Sean Neville)	625	(24)
The Relationship between Standards and Design Patterns	626	(1)
Survey of Standards Processes and Organizations	627	(2)
Business Process Components and Intra-web Service Messaging	629	(2)
ebXML and the Electronic Business Messaging Service (ebMS)	631	(3)
Business Process Execution Language for Web Services (BEPL4WS)	634	(2)
Web Service Choreography Interface (WSCI)	636	(1)
Java Business Process Component Standards	637	(2)
WS-*	639	(8)
Conclusions	647	(2)
Bibliography	649	(10)
Index	659

Excerpts

This is a book about enterprise integration using messaging. It does not document any particular technology or product. Rather, it is designed for developers and integrators using a variety of messaging products and technologies, such as Message-oriented middleware (MOM) and EAI suites offered by vendors such as IBM (WebSphere MQ Family), Microsoft (BizTalk), TIBCO, WebMethods, SeeBeyond, Vitria, and others. Java Message Service (JMS) implementations incorporated into commercial and open source J2EE application servers as well as standalone products. Microsoft's Message Queuing (MSMQ), accessible through several APIs, including the System.Messaging libraries in Microsoft .NET. Emerging Web services standards that support asynchronous Web services (for example, WS-ReliableMessaging) and the associated APIs such as Sun Microsystems' Java API for XML Messaging (JAXM) or Microsoft's Web Services Extensions (WSE). Enterprise integration goes beyond creating a single application with a distributedn-tier architecture, which enables a single application to be distributed across several computers. Whereas one tier in a distributed application cannot run by itself, integrated applications are independent programs that can each run by themselves, yet that function by coordinating with each other in a loosely coupled way. Messaging enables multiple applications to exchange data or commands across the network using a "send and forget" approach. This allows the caller to send the information and immediately go on to other work while the information is transmitted by the messaging system. Optionally, the caller can later be notified of the result through a callback. Asynchronous calls and callbacks can make a design more complex than a synchronous approach, but an asynchronous call can be retried until it succeeds, which makes the communication much more reliable. Asynchronous messaging also enables several other advantages, such as throttling of requests and load balancing. Who Should Read This Book This book is designed to help application developers and system integrators connect applications using message-oriented integration tools: Application architects and developerswho design and build complex enterprise applications that need to integrate with other applications. We assume that you're developing your applications using a modern enterprise application platform such as the Java 2 Platform, Enterprise Edition (J2EE), or the Microsoft .NET Framework. This book will help you connect the application to a messaging layer and exchange information with other applications. This book focuses on the integration of applications, not on building applications; for that, we refer you toPatterns of Enterprise Application Architectureby Martin Fowler. Integration architects and developerswho design and build integration solutions connecting packaged or custom applications. Most readers in this group will have experience with one of the many commercial integration tools like IBM WebSphere MQ, TIBCO, WebMethods, SeeBeyond, or Vitria, which incorporate many of the patterns presented in this book. This book helps you understand the underlying concepts and make confident design decisions using a vendor-independent vocabulary. Enterprise architectswho have to maintain the "big picture" view of the software and hardware assets in an enterprise. This book presents a consistent vocabulary and graphical notation to describe large-scale integration solutions that may span many technologies or point solutions. This language is also a key enabler for efficient communication between the enterprise architect and the integration and application architects and developers. What You Will Learn This book does not attempt to make a business case for enterprise application integration; the focus is on how to make it work. Yo