.NODE

Appendix B. Service Models Reference

Services can be categorized based on the nature of the logic they encapsulate and the manner in which they are typically utilized within SOA. This book introduces a series of these categories and calls them service models.

Because service model descriptions are interspersed in various chapters, we provide a master list in this Appendix for quick reference purposes. Note that services can (and often do) belong to more than one service model.

Table B-1. An overview of service models.

Service Model

Description

Chapters

Application service

A generic category used to represent services that contain logic derived from a solution or technology platform. Services are generally distinguished as application services when creating service abstraction layers.

9, 11, 12, 15

Business service

A generic category used to represent services that contain business logic. When establishing specialized service layers, services that fall into the business service layer are collectively referred to as business services. However, individually these services are classified as entity-centric or task-centric business services.

5, 9, 11, 12, 15

Controller service

A service that composes others. Variations of this model exist, depending on the position of the controller in the composition hierarchy. The parent controller service can be classified as the master controller and a service that composes a subset of a larger composition can be labeled a sub-controller.

5

Coordinator services

Three service models are derived from the concept of coordination: the coordinator, the atomic transaction coordinator, and the business activity coordinator. All three models are specific to the WS-Coordination specification and related protocols.

6

Entity-centric business service

A business process-agnostic variation of the business service that represents one or more related business entities. This type of service is created when establishing a business service layer.

9, 11, 12, 15

Hybrid service

A service that contains both business and application logic. Most services created as part of traditional distributed solutions fall into this category. When organizing services into abstraction layers, hybrid services are considered part of the application service layer.

9

Integration service

An application service that also acts as an endpoint to a solution environment for cross-application integration purposes.

9

Process service

A service that represents a business process as implemented by an orchestration platform and described by a process definition. Process services reside in the orchestration service layer.

6, 9, 11, 12, 16

Task-centric business service

A business process-specific variation of the business service that represents an atomic unit of process logic. Task-centric services are different from process services in that the process logic is provided by the underlying service logic, not by a separate process definition.

9, 11, 12, 15

Utility service

A service that offers reusable logic. This category is primarily intended for the classification of solution-agnostic application services. However, it also can be used to refer to reusable business services.

5, 9

Wrapper service

A type of integration service that encapsulates and exposes logic residing within a legacy system. Wrapper services are commonly provided by legacy system vendors and therefore frequently introduce non-standardized interfaces.

9


Introduction

Case Studies

Part I: SOA and Web Services Fundamentals

Introducing SOA

The Evolution of SOA

Web Services and Primitive SOA

Part II: SOA and WS-* Extensions

Web Services and Contemporary SOA (Part I: Activity Management and Composition)

Web Services and Contemporary SOA (Part II: Advanced Messaging, Metadata, and Security)

Part III: SOA and Service-Orientation

Principles of Service-Orientation

Service Layers

Part IV: Building SOA (Planning and Analysis)

SOA Delivery Strategies

Service-Oriented Analysis (Part I: Introduction)

Service-Oriented Analysis (Part II: Service Modeling)

Part V: Building SOA (Technology and Design)

Service-Oriented Design (Part I: Introduction)

Service-Oriented Design (Part II: SOA Composition Guidelines)

Service-Oriented Design (Part III: Service Design)

Service-Oriented Design (Part IV: Business Process Design)

Fundamental WS-* Extensions

SOA Platforms

Appendix A. Case Studies: Conclusion

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Service-Oriented Architecture. Concepts, Technology, and Design
Service-Oriented Architecture (SOA): Concepts, Technology, and Design
ISBN: 0131858580
EAN: 2147483647
Year: 2004
Pages: 150
Authors: Thomas Erl
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