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 Asynchronous Queuing (Little, Rischbeck, Simon) Home > Service Messaging Patterns > Asynchronous Queuing How can a service and its consumers accommodate isolated failures and avoid unnecessarily locking resources?   Problem When a service capability requires that consumers interact with it synchronously, it can inhibit performance and compromise reliability. Solution A service can exchange messages with its consumers via an intermediary buffer, allowing service and consumers to process messages independently by remaining temporally decoupled. Application Queuing technology needs to be incorporated into the surrounding architecture, and back-up stores may also be required. Impacts There may be no acknowledgement of successful message delivery, and atomic transactions may not be possible. Principles Standardized Service Contract, Service Loose Coupling, Service Statelessnes Architecture Inventory, Composition   Service A sends a message to Service B, which is intercepted and stored by an intermediary queue (1). The queue the forwards the message to Service B (2), and while Service B is processing the message, Service A remains released from memory (3). After completing its processing, Service B issues a response message back to Service A, which is also received and stored by the intermediary queue (4). Service A receives the response (5) and completes processing of the response, all the while Service B is deactivated (6). Audio Podcast This pattern is discussed as part of the audio podcast: The ESB and Related Messaging Patterns   Related Patterns in This Catalog Atomic Service Transaction (Erl), Event-Driven Messaging (Little, Rischbeck, Simon), Message Metadata (Erl), Reliable Messaging (Little, Rischbeck, Simon), Service Agent (Erl), Service Callback (Karmarkar), Service Instance Routing (Karmarkar), State Messaging (Karmarkar) 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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