Select a Pattern Agnostic Capability Agnostic Context Agnostic Sub-Controller Asynchronous Queuing Atomic Service Transaction Brokered Authentication Canonical Expression Canonical Protocol Canonical Resources Canonical Schema Canonical Schema Bus Canonical Versioning Capability Composition Capability Recomposition Compatible Change Compensating Service Transaction Composition Autonomy Concurrent Contracts Contract Centralization Contract Denormalization Cross-Domain Utility Layer Data Confidentiality Data Format Transformation Data Model Transformation Data Origin Authentication Decomposed Capability Decoupled Contract Direct Authentication Distributed Capability Domain Inventory Dual Protocols Enterprise Inventory Enterprise Service Bus Entity Abstraction Event-Driven Messaging Exception Shielding Federated Endpoint Layer File Gateway Functional Decomposition Intermediate Routing Inventory Endpoint Legacy Wrapper Logic Centralization Message Screening Messaging Metadata Metadata Centralization Multi-Channel Endpoint Non-Agnostic Context Official Endpoint Orchestration Partial State Deferral Partial Validation Policy Centralization Process Abstraction Process Centralization Protocol Bridging Proxy Capability Redundant Implementation Reliable Messaging Rules Centralization Schema Centralization Service Agent Service Broker Service Callback Service Data Replication Service Decomposition Service Encapsulation Service Facade Service Grid Service Instance Routing Service Layers Service Messaging Service Normalization Service Perimeter Guard Service Refactoring State Messaging State Repository Stateful Services Termination Notification Three-Layer Inventory Trusted Subsystem UI Mediator Utility Abstraction Validation Abstraction Version Identification Overview     History     Acknowledgements     Podcasts     Notification Form     Feedback Form     Press Release #1     Press Release #2     Press Release #3 Master SOA Design Pattern Catalog     Master Pattern List (alphabetical)     Master Pattern List (by category)     Master Pattern List with Page Numbers (PDF)     Master Pattern List (Text)     Pattern Notation     Pattern Profiles     Symbol Legend     Pattern Contribution Form SOA Candidate Patterns     SOA Patterns Review Committee     Candidate Patterns Overview     Candidate Patterns List     Candidate Pattern Contribution Form     Candidate Pattern Feedback Form     SOA Pattern Template Design Pattern Basics     What's a Design Pattern?     What's a Design Pattern Language?     What's a Compound Pattern? Supplemental     SOA Patterns and Application Technologies     SOA Design Patterns Historical Influences     SOA Design Patterns and Design Principles     SOA Design Patterns and Design Granularity     Legal Resources     Design Patterns Publications     Reference Posters     SOAPrinciples.com     WhatIsSOA.com     SOA Visio Stencil Legacy Wrapper (Erl, Roy) Home > Legacy Encapsulation Patterns > Legacy Wrapper How can wrapper services with non-standard contracts be prevented from spreading indirect consumer-to-implementation coupling?   Problem Wrapper services required to encapsulate legacy logic are often forced to introduce a non-standard service contract with high technology coupling requirements, resulting in a proliferation of implementation coupling throughout all service consumer programs. Solution The non-standard wrapper service can be replaced by or further wrapped with a standardized service contract that extracts, encapsulates, and possibly eliminates legacy technical details from the contract. Application A custom service contract and required service logic need to be developed to represent the proprietary legacy interface. Impacts The introduction of an additional service adds a layer of processing and associated performance overhead. Principles Standardized Service Contract, Service Loose Coupling, Service Abstraction Architecture Service Tight coupling of the service logic to both the legacy API and the service contract alleviates service consumers from implementation coupling. Related Patterns in This Catalog Data Format Transformation (Erl), Data Model Transformation (Erl), Entity Abstraction (Erl), File Gateway (Roy), Multi-Channel Endpoint (Roy), Protocol Bridging (Little, Rischbeck, Simon), Rules Centralization (Erl), Service Data Replication (Erl), Utility Abstraction (Erl) Related Patterns in Other Catalogs Adapter (Gamma, Helm, Johnson, Vlissides) Related Service-Oriented Computing Goals Increased Vendor Diversification Options, Reduced IT Burden This page contains excerpts from: SOA Design Patterns by Thomas Erl Foreword by Grady Booch With contributions from David Chappell, Jason Hogg, Anish Karmarkar, Mark Little, David Orchard, Satadru Roy, Thomas Rischbeck, Arnaud Simon, Clemens Utschig, Dennis Wisnosky, and others. (ISBN: 0136135161, Hardcover, Full-Color, 400+ Illustrations, 865 pages) For more information about this book, visit www.soabooks.com.

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