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Implementing SOA: Total Architecture in Practice
Putting Service-Oriented Architecture (SOA) into Practice
“This book is a must-have for enterprise architects implementing SOA. Through practical examples, it explains the relationship between business requirements, business process design, and service architecture. By tying the SOA implementation directly to business value, it reveals
the key to ongoing success and funding.”
—Maja Tibbling, Lead Enterprise Architect, Con-way, Inc.
“While there are other books on architecture and the implementation of ESB, SOA, and related technologies, this new book uniquely captures the knowledge and experience of the real world. It shows how you can transform requirements and vision into solid, repeatable, and value-added architectures. I heartily recommend it.”
—Mark Wencek, SVP, Consulting Services & Alliances, Ultimo Software Solutions, Inc.
In his first book, Succeeding with SOA, Paul Brown explained that if enterprise goals are to be met, business processes and information systems must be designed together as parts of a total architecture. In this second book, Implementing SOA, he guides you through the entire process of designing and developing a successful total architecture at both project and enterprise levels. Drawing on his own extensive experience, he provides best practices for creating services and leveraging them to create robust and flexible SOA solutions.
Coverage includes
* Evolving the enterprise architecture towards an SOA while continuing to deliver business value on a project-by-project basis
* Understanding the fundamentals of SOA and distributed systems, the dominant architectural issues, and the design patterns for addressing them
* Understanding the distinct roles of project and enterprise architects and how they must collaborate to create an SOA
* Understanding the need for a comprehensive total architecture approach that encompasses business processes, people, systems, data, and infrastructure
* Understanding the strategies and tradeoffs for implementing robust, secure, high-performance, and high-availability solutions
* Understanding how to incorporate business process management (BPM) and business process monitoring into the enterprise architectureWhether you’re defining an enterprise architecture or delivering individual SOA projects, this book will give you the practical advice you need to get the job done.
CONTENTS:
Preface xxvii
Part I: Fundamentals 1
Chapter 1: SOA and the Enterprise 3
The Challenge 4
The Concept of Total Architecture 5
Architecture Is Structure for a Purpose 6
Constant Changes 7
Total Architecture Synthesis 8
Making Total Architecture Work in Your Enterprise 9
Key Overview Questions 10
Chapter 2: Architecture Fundamentals 11
Structural Organization 11
Functional Organization 15
Collaborative Behavior 20
Total Architecture 26
Nonfunctional Requirements 27
Refinement 28
The Role of the Architect 29
Enterprise Architecture 30
Summary 34
Key Architecture Fundamentals Questions 35
Suggested Reading 36
Chapter 3: Service Fundamentals 37
What Is a Service? 37
Operations 38
Service Interfaces 47
The Rationale Behind Services 54
Summary 58
Key Service Fundamentals Questions 59
Suggested Reading 60
Chapter 4: Using Services 61
Service Interaction Patterns 61
Service Access 67
Access Control 72
Service Request Routing 76
Service Composition 80
Locating Services 85
Enterprise Architecture for Services 86
Summary 87
Key Service Utilization Questions 88
Suggested Reading 89
Chapter 5: The SOA Development Process 91
What Is Different about SOA Development? 91
The Overall Development Process 92
Architecture Tasks 94
Architecture in Context 96
Total Architecture Synthesis (TAS) 97
Beware of Look-Alike Processes! 105
Manage Risk: Architect Iteratively 106
Summary 108
Key Development Process Questions 108
Suggested Reading 109
Part II: The Business Process Perspective 111
Chapter 6: Processes 113
Triggers, Inputs, and Results 114
Related Processes 115
Process Maturity 116
Continuous Processes 119
Structured Processes 120
Summary 121
Key Process Questions 122
Suggested Reading 122
Chapter 7: Initial Project Scoping 123
Assembling the Business Process Inventory 124
Conducting Interviews 125
Documenting the Inventory 128
Ranking Business Processes 141
Organizing the Remaining Work 147
Summary 149
Key Scoping Questions 150
Chapter 8: The Artifice of Requirements 151
Differentiation 153
Characterizing Processes 159
Patterns of Interaction 163
Interaction Patterns Characterize Participants 171
Requirements Reflect Design 172
Summary 175
Key Requirements Questions 177
Suggested Reading 178
Chapter 9: Business Process Architecture 179
Results 180
Participants and Their Roles 182
Activities and Scenarios 186
Modeling Scenarios 191
Modeling Interactions 198
How Much Detail Is Enough? 204
Guidelines for Using Activity Diagrams 206
Summary 207
Key Business Process Architecture Questions 208
Suggested Reading 209
Chapter 10: Milestones 211
Basic Process Milestones 211
Variations in Milestone Sequences 214
Grouped Milestones 215
Recognizing Milestones Requires Design 216
Using Milestones to Reduce Inter-Process Coupling 217
Summary 218
Key Milestone Questions 219
Chapter 11: Process Constraints 221
Business Process Constraints Drive System Constraints 222
Performance Constraints 224
High Availability and Fault Tolerance 231
Security 238
Reporting, Monitoring, and Management 240
Exception Handling 242
Test and Acceptance 243
Compliance Constraints 245
Summary 246
Key Process Constraint Questions 247
Suggested Reading 248
Chapter 12: Related Processes 249
Identifying Services 252
Triggering Events 258
Summary 264
Key Related Process Questions 265
Chapter 13: Modeling the Domain 267
UML Class Notation 269
ATM Example Domain Model 274
Reverse Engineering the Domain Model 276
Domain Modeling Summary 277
Key Domain Modeling Questions 279
Suggested Reading 279
Chapter 14: Enterprise Architecture: Process and Domain Modeling 281
Process and Domain Modeling Responsibilities 282
Establishing Standards and Best Practices 283
Managing Process and Domain Knowledge Transfer 285
Reviewing Project Models 286
Maintaining the Business Process and Domain Model Repository 287
Defining Business Process Patterns 288
Defining Common Data Model Representations 288
Summary 289
Key Enterprise Process and Domain Modeling Questions 290
Part III: The Systems Perspective 291
Chapter 15: Systems Architecture Overview 293
The Challenge of Architecting Distributed Systems 294
Learning from the CORBA Experience 294
Efficiently Exploring Architectures 300
Summary 303
Key Systems Architecture Overview Questions 304
Chapter 16: Top-Level Systems Architecture 305
First-Cut Structure 305
Initial Evaluation 307
Communications and Modularization 309
Service Identification and Performance 312
Modeling System Interactions 312
Modeling Deployment 318
Addressing Performance 322
Early Architecture Evaluation 325
Key Top-Level Systems Architecture Questions 327
Suggested Reading 328
Part IV: Communications 329
Chapter 17: Transport 331
Transport Technology 332
Selecting Transports 336
Messaging Server Topology 340
Capacity 345
Point-to-Point Interaction Patterns 347
Point-to-Point Intermediaries 348
Transport-Supplied Services 350
Summary 351
Key Transport Questions 351
Suggested Reading 352
Chapter 18: Adapters 353
API-Based Adapters 354
Database-Based Adapters 355
Combining API and Database Approaches 356
File-Based Adapters 357
Protocol-Based Adapters 357
Documenting Adapter Usage 358
Summary 359
Key Adapter Questions 360
Chapter 19: Enterprise Architecture: Communications 361
Defining a Communications Strategy 361
Interaction Standards 362
Standardizing Adapters 363
Summary 364
Key Enterprise Architecture Communications Questions 364
Part V: Data and Operations 367
Chapter 20: Data Challenges 369
Chapter 21: Messages and Operations 371
Message Semantics and Operation Names 371
Transport Destinations and Operation Bundling 374
Content Representation 377
Content Transformation 378
Reference Data in Content Transformation 380
Summary 381
Key Messages and Operations Questions 381
Chapter 22: Data Consistency: Maintaining One Version of the Truth 383
Approaches to Maintaining Data Consistency 384
Cached Data with a Single System of Record 385
Coordinated Updates via Distributed Transactions 390
Edit Anywhere, Reconcile Later 390
Dealing with Data Inconsistencies 391
Data Management Business Processes 393
Summary 394
Key Data Consistency Questions 394
Suggested Reading 395
Chapter 23: Common Data Models (CDM) 397
What Is a Common Data Model? 397
CDM Relationship to the Domain Model 402
The Need for Multiple CDM Representations 405
Planning for CDM Changes 407
When to Use Common Data Models 411
Summary 415
Key Common Data Model Questions 416
Chapter 24: Identifiers (Unique Names) 417
Identity (Unique Name) Authorities 418
Hierarchical Identifiers 419
Coping with Identity Errors 423
Mapping Identifiers 429
Summary 433
Key Identifier Questions 434
Chapter 25: Results Validation 435
Checking Enumerated Values 436
Where and When to Validate 437
Summary 438
Key Data Validation Questions 439
Chapter 26: Enterprise Architecture: Data 441
Naming Schemes 441
Architecting Content Transformation 443
Systems of Record 445
Common Data Models 446
Identifiers 447
Data Quality Management 448
Summary 449
Key Enterprise Architecture Data Questions 450
Part VI: Coordination 451
Chapter 27: Coordination and Breakdown Detection 453
Activity Execution Management Patterns (AEMPs) Involving Interactions 454
Coordination Pattern Styles 456
Fire-and-Forget Coordination Patterns 457
Request-Reply Patterns 460
Delegation 465
Delegation with Confirmation 467
Summary 468
Key Coordination Questions 469
Chapter 28: Transactions: Coordinating Two or More Activities 471
Two-Phase Commit Distributed Transactions 472
Limitations of Two-Phase Commit Protocols 475
Compensating Transactions 476
Working around the Limitations of Compensating Transactions 476
Summary 478
Key Transaction Questions 479
Suggested Reading 479
Chapter 29: Process Monitors and Managers 481
Process Monitoring 483
Minimizing the Impact of Monitoring Breakdowns 484
The Process Manager as a Monitor 485
Process Management Limitations 486
Summary 488
Key Process Monitoring and Management Questions 488
Chapter 30: Detecting and Responding to Breakdowns 489
Selecting Coordination Patterns to Improve Breakdown Detection 489
Responding to Breakdowns 493
Summary 504
Key Breakdown Detection and Recovery Questions 505
Chapter 31: Enterprise Architecture: Coordination 507
Preferred Coordination Patterns 507
Breakdown Recording 509
Breakdown Annunciation 510
Recovery Processes 511
Summary 511
Key Enterprise Coordination Questions 512
Part VII: High Availability, Fault Tolerance, and Load Distribution 513
Chapter 32: High Availability and Fault Tolerance Fundamentals 515
Fault Tolerance Strategies 516
Failure Detection Strategies 517
Failover Management 519
Redirecting Clients 520
Summary 522
Key High-Availability and Fault Tolerance Questions 523
Chapter 33: Stateless and Stateful Failover 525
Stateless and Stateful Components 525
Stateless Failover 525
Saving Work in Progress through Coordination 526
Stateful Failover 528
Storage Replication 530
Summary 540
Key Failover Questions 541
Suggested Reading 541
Chapter 34: Multiple Component Failover 543
Intra-Site versus Inter-Site Failover 543
Clustering: An Intra-Site Failover Technique 545
Coordinating Peer Application Failover with Asynchronous Replication 546
Making a Business Process Fault-Tolerant 548
Summary 550
Key Multi-Component Failover Questions 551
Chapter 35: Workload Distribution 553
Work Assignment Strategies 553
Distribution Management and Work Completion 554
The Sequencing Problem 556
Access to Shared Persistent State 557
Geographic Workload Distribution 558
Summary 558
Key Workload Distribution Questions 559
Chapter 36: Enterprise Architecture: Fault Tolerance, High Availability, and Load Distribution 561
Business Process Categorization 563
Information Storage 565
Individual Component and Service Failover Patterns 565
Composite Patterns for FT and HA Services 566
Composite Patterns for FT and HA Business Processes 568
Summary 568
Key Enterprise Fault Tolerance, High-Availability, and Load Distribution Questions 569
Suggested Reading 569
Part VIII: Completing the Architecture 571
Chapter 37: Process Security 573
Security Information Classification 574
Identity and Authentication 574
Authorization 576
Encryption 579
Digital Signatures 580
Other Security-Related Requirements 580
Reference Data Servers and Performance 581
Trust Zones 582
Channel Enforcement 583
Zone Enforcement and Policy Agents 585
Multi-Zone Security 586
Summary 587
Key Security Questions 588
Suggested Reading 589
Chapter 38: Process Monitoring 591
Performance Monitoring 592
Monitoring Process Status 594
Supervisory Processes 595
The Impact of Monitoring on Performance 596
Summary 596
Key Process Monitoring Questions 597
Chapter 39: Architecture Evaluation 599
Usability 600
Performance 600
Cost and Schedule Feasibility 612
Observability 613
Ability to Evolve 613
Ability to Handle Stress Situations 614
Summary 615
Key Architecture Evaluation Questions 616
Suggested Reading 617
Chapter 40: Testing 619
Unit Testing, Test Harnesses, and Regression Testing 620
Integration Testing and Order of Assembly 621
Environments for Functional and System Testing 622
Performance Testing 623
Failure Mode Testing 627
Summary 628
Key Testing Questions 628
Part IX: Advanced Topics 631
Chapter 41: Representing a Complex Process 633
Eliding Communications Detail 634
Eliding Participant Activity Details 634
Eliding Supporting Participants 636
Abstracting Subprocesses 638
Summary 639
Key Complex Process Representation Questions 639
Chapter 42: Process Management and Workflow 641
Process Management 642
Styles of Work Assignment 647
Initiating Workflow 649
Making the Management Process Fault Tolerant 649
Human Interfaces 656
Related Processes 660
Prioritized Work 663
Dynamic Work Assignments 665
Dynamic Result and Process Definitions 666
Summary 668
Key Process Management and Workflow Questions 669
Suggested Reading 670
Chapter 43: The Enterprise Architecture Group 671
Half a Group Is Better than None—But Not Good Enough 672
Best Practice Development 672
Knowledge Transfer 673
Governance 675
Designing with Evolving Requirements 675
Summary 681
Key Enterprise Architecture Group Questions 682
Afterword 683
Focus Your Work 683
Seek the Expertise of Others 684
Be Pragmatic, But Consider the Long View 685
Index 687
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