View source for Object request broker

In [[Distributed computing|distributed computing]], an '''object request broker''' ('''ORB''') is a concept of a [[Middleware (distributed applications)|middleware]], which allows program calls to be made from one computer to another via a [[Computer network|computer network]], providing location transparency through [[Remote procedure call|remote procedure call]]s. ORBs promote interoperability of distributed object systems, enabling such systems to be built by piecing together objects from different vendors, while different parts communicate with each other via the ORB. [[Common Object Request Broker Architecture]] (by [[Organization:Object Management Group|Object Management Group]]) standardizes the way ORB may be implemented.
== Overview ==
ORBs assumed to handle the transformation of in-process data structures to and from the raw byte sequence, which is transmitted over the network.  This is called [[Marshalling (computer science)|marshalling]] or [[Serialization|serialization]].  In addition to marshalling data, ORBs often expose many more features, such as distributed transactions, directory services or real-time scheduling.  Some ORBs, such as CORBA-compliant systems, use an [[Interface description language|interface description language]] to describe the data that is to be transmitted on remote calls.<ref name="ibm-orb">{{cite web
 | url = http://pic.dhe.ibm.com/infocenter/wasinfo/v8r5/index.jsp?topic=%2Fcom.ibm.websphere.express.doc%2Fae%2Ftorb_ep2.html
 | title = Object Request Brokers
 | date = 2013-11-05 | access-date = 2013-12-22
 | publisher = [[Company:IBM|IBM]]
}}</ref><ref>{{cite web
 | url = http://www.cs.wustl.edu/~schmidt/corba-overview.html
 | title = Overview of CORBA
 | date = 2006-09-28 | access-date = 2013-12-22
 | publisher = wustl.edu
}}</ref>

In [[Object-oriented language|object-oriented language]]s (.e.g. java), an ORB actually provides a [[Software framework|framework]] which enables remote objects to be used over the network, in the same way as if they were local and part of the same [[Process (computing)|process]].  On the client side, so-called ''stub'' objects are created and invoked, serving as the only part visible and used inside the client application.  After the stub's methods are invoked, the client-side ORB performs the marshalling of invocation data, and forwards the request to the server-side ORB.  On the server side, ORB locates the targeted object, executes the requested operation, and returns the results.  Having the results available, the client's ORB performs the demarshalling and passes the results back into the invoked stub, making them available to the client application.  The whole process is transparent, resulting in remote objects appearing as if they were local.<ref name="ibm-orb" />

== Implementations ==
* CORBA - Common Object Request Broker Architecture.
* [[Software:Internet Communications Engine|ICE]] - the [[Software:Internet Communications Engine|Internet Communications Engine]]
* .NET Remoting - object remoting library within Microsoft's .NET Framework
* [[Organization:Windows Communication Foundation|Windows Communication Foundation]] (WCF)
* ORBexpress - Real-time and Enterprise ORBs by [[Company:Objective Interface Systems|Objective Interface Systems]]
* Orbix - An Enterprise-level CORBA ORB from IONA Technologies
* [[Distributed Component Object Model|DCOM]] - the Distributed Component Object Model from [[Company:Microsoft|Microsoft]]
* [[Java remote method invocation|RMI]] - the Remote Method Invocation Protocol from [[Company:Sun Microsystems|Sun Microsystems]]
* ORBit - an open-source CORBA ORB used as middleware for [[Software:GNOME|GNOME]]
* The ACE ORB - a CORBA implementation from the [http://www.dre.vanderbilt.edu/ Distributed Object Computing (DOC) Group]
* omniORB - Free CORBA ORB [http://www.omniorb.net]

== See also ==
*{{Annotated link|Message broker}}
*{{Annotated link|Distributed object communication}}
*{{Annotated link|Distributed object}}
*{{Annotated link|D-Bus}}

== References ==
{{Reflist}}

[[Category:Middleware]]



{{Sourceattribution|Object request broker}}