Editing Middleware (distributed applications) (section)

==Types==

===Message-oriented middleware===
[[Message-oriented middleware]] (MOM) <ref>Curry, Edward. 2004. [http://www.mendeley.com/download/public/1652511/4338215212/cce0f06f047faa57879a1fc36a8e8d6d754d2f6a/dl.pdf "Message-Oriented Middleware"] {{Dead link|date=January 2019 |bot=InternetArchiveBot |fix-attempted=yes }}. In Middleware for Communications, ed. Qusay H Mahmoud, 1-28. Chichester, England: John Wiley and Sons. {{doi|10.1002/0470862084.ch1}}. {{ISBN|978-0-470-86206-3}}</ref> is middleware where transactions or event notifications are delivered between disparate systems or components by way of messages, often via an [[enterprise messaging system]].  With MOM, messages sent to the client are collected and stored until they are acted upon, while the client continues with other processing.

; Enterprise messaging
: An [[enterprise messaging system]] is a type of middleware that facilitates message passing between disparate systems or components in standard formats, often using [[XML]], [[SOAP]] or [[web services]].  As part of an enterprise messaging system, [[message broker]] software may queue, duplicate, translate and deliver messages to disparate systems or components in a messaging system.

; Enterprise service bus
: [[Enterprise service bus]] (ESB) is defined by the [[Burton Group]]<ref name="ms-on-esb">{{Cite web|url=http://msdn.microsoft.com/en-us/library/aa475433(BTS.10).aspx|title=Microsoft on the Enterprise Service Bus (ESB)|date=August 2005|quote=The ESB label simply implies that a product is some type of integration middleware product that supports both MOM and Web services protocols.}}</ref> as "some type of integration middleware product that supports both [[message-oriented middleware]] and [[Web services]]".

===Intelligent middleware===
<ref>[http://www.cougaarsoftware.com/files/CSI_ActiveEdge.pdf Choosing the Right Middleware] {{Webarchive|url=https://web.archive.org/web/20120402121113/http://www.cougaarsoftware.com/files/CSI_ActiveEdge.pdf |date=2012-04-02 }} </ref>
Intelligent [[Middleware]] (IMW) provides real-time intelligence and event management through [[intelligent agents]]. The IMW manages the real-time processing of high volume sensor signals and turns these signals into intelligent and actionable business information. The actionable information is then delivered in end-user power dashboards to individual users or is pushed to systems within or outside the enterprise. It is able to support various heterogeneous types of hardware and software and provides an API for interfacing with external systems. It should have a highly scalable, [[distributed architecture]] which embeds intelligence throughout the network to transform raw data systematically into actionable and relevant knowledge. It can also be packaged with tools to view and manage operations and build advanced network applications most effectively.

==={{Anchor|EMBEDDED}}Content-centric middleware===
Content-centric middleware offers a simple ''provider-consumer'' abstraction through which applications can issue requests for uniquely identified content, without worrying about where or how it is obtained. Juno is one example, which allows applications to generate content requests associated with high-level delivery requirements.<ref>[http://www.dcs.kcl.ac.uk/staff/tysong/files/PhD.pdf Juno] {{Webarchive|url=https://web.archive.org/web/20110426045143/http://www.dcs.kcl.ac.uk/staff/tysong/files/PhD.pdf |date=2011-04-26 }} , Gareth Tyson, A Middleware Approach to Building Content-Centric Applications. PhD Thesis, Lancaster University (2010).</ref> The middleware then adapts the underlying delivery to access the content from sources that are best suited to matching the requirements. This is therefore similar to [[Publish/subscribe]] middleware, as well as the [[Content-centric networking]] paradigm.

; Remote procedure call
: [[Remote procedure call]] middleware enables a client to use services running on remote systems.  The process can be [[Synchronization (computer science)|synchronous]] or  [[Asynchrony (computer programming)|asynchronous]].
; Object request broker
: With [[object request broker]] middleware, it is possible for applications to send objects and request services in an object-oriented system.
; SQL-oriented data access
: [[:Category:SQL data access|SQL-oriented Data Access]] is middleware between applications and database servers.
; Embedded middleware
: Embedded middleware provides communication services and software/[[firmware]] integration interface that operates between embedded applications, the embedded operating system, and external applications.

===Policy Appliances===
Policy appliance is a generic term referring to any form of middleware that manages policy rules. They can mediate between data owners or producers, data aggregators, and data users. Among heterogeneous institutional systems or networks they may be used to enforce, reconcile, and monitor agreed information management policies and laws across systems (or between jurisdictions) with divergent information policies or needs. Policy appliances can interact with smart data (data that carries with it contextual relevant terms for its own use), [[intelligent agent]]s (queries that are self-credentialed, authenticating, or contextually adaptive), or [[context awareness|context-aware]] applications to control information flows, protect security and confidentiality, and maintain privacy. Policy appliances support policy-based information management processes by enabling rules-based processing, selective disclosure, and accountability and oversight.<ref>{{Citation |title=Designing Technical Systems to Support Policy: Enterprise Architecture, Policy Appliances, and Civil Liberties |date=2010 |work=Emergent Information Technologies and Enabling Policies for Counter-Terrorism |url=https://doi.org/10.1109/9780470874103.ch22 |access-date=2025-04-28 |publisher=IEEE |isbn=978-0-470-87410-3}}</ref> 

Examples of policy appliance technologies for rules-based processing include analytic filters, [[Contextual searching|contextual search]], semantic programs, labeling and wrapper tools, and [[Digital rights management|DRM]], among others; policy appliance technologies for selective disclosure include anonymization, content personalization, subscription and publishing tools, among others; and, policy appliance technologies for accountability and oversight include [[authentication]], authorization, immutable and non-repudiable logging, and audit tools, among others. 

===Other===
Other sources{{Citation needed|date=September 2010}} include these additional classifications:
*[[Transaction Processing System|Transaction processing monitors]]{{snd}} provides tools and an environment to develop and [[Software deployment|deploy]] [[distributed application]]s.<ref>{{Cite book|title=Performance-Oriented Application Development for Distributed Architectures: Perspectives for Commercial and Scientific Environments|last=Gerndt|first=Michael|publisher=IOS PR, Inc.|year=2002|isbn=978-1586032678}}</ref>{{Citation needed|date=September 2010}}
*[[Application server]]s{{snd}} software installed on a computer to facilitate the serving (running) of other applications.<ref>{{Cite book|title=Network Dictionary|last=Dong|first=Jielin|publisher=Javvin Press|year=2007|isbn=978-1602670006}}</ref>{{Citation needed|date=September 2010}}