Basic Terminologies for Open esb

Coupling
coupling or dependency is the degree to which each program module relies on each one of the other modules

Loose coupling
Loose coupling describes an approach where integration interfaces are developed with minimal assumptions between the sending/receiving parties, thus reducing the risk that a change in one application/module will force a change in another application/module.

Service
A service is a function that is well-defined, self-contained, and does not depend on the context or state of other services.

SOA
-Service-Oriented Architecture (SOA) is a software architecture where functionality is grouped around business processes and packaged as interoperable services.

-SOA also describes IT infrastructure which allows different applications to exchange data with one another as they participate in business processes.

-The aim is a loose coupling of services with operating systems, programming languages and other technologies which underlie applications.

-Web services can be used to implement a service-oriented architecture.

JBI -

Java Business Integration (JBI) is a specification developed under the Java Community Process (JCP) for an approach to implementing a service-oriented architecture (SOA). The JCP reference is JSR 208 for JBI 1.0 and JSR 312 for JBI 2.0.

ESB Architecture :-
In an enterprise architecture making use of an ESB, an application will communicate via the bus, which acts as a message broker between applications.


Advantage of ESB Architecture :-

The primary advantage of such an approach is that it reduces the number of point-to-point connections required to allow applications to communicate.


What is ESB ?

1. ESB is the piece of software that lies between the business applications and enables communication among them.
2. ESB replaces all direct contact with the applications on the bus, so that all communication takes place via the bus.
3. It uses the enterprise message model which is a standard set of messages that the ESB will both transmit and receive.


Benefits

1.Faster and cheaper accommodation of existing systems.
2.Increased flexibility; easier to change as requirements change.
3.Standards-based.


Disadvantages

1.Enterprise Message Model is usually required, resulting in additional management overhead.
2.Requires ongoing management of message versions to ensure the intended benefit of loose coupling.
3.It normally requires more hardware than simple point to point messaging.
4.Extra overhead and increased latency caused by messages traversing the extra ESB layer, especially as compared to point to point communications.

Enterprise Application
-An enterprise application is typically a software application hosted on an application server which simultaneously provides services to a large number of users, via a network

-It is Java 2 Platform Enterprise Edition application is any deployable unit of J2EE functionality. This can be a single J2EE module or a group of modules packaged into an EAR file along with a J2EE application deployment descriptor.



Composite Application
-A composite application is a transactional application consisting of business functionality and information from varied information sources.

-Composite applications are both a form of integration, as well as application development.


What is Open ESB?
Project Open ESB implements an Enterprise Service Bus (ESB) runtime using Java Business Integration as the foundation. This allows easy integration of web services to create loosely coupled enterprise class composite applications.