15.01.2013 Views

U. Glaeser

U. Glaeser

U. Glaeser

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

FIGURE 40.8<br />

The application server uses CORBA and JavaBeans components or objects. Transaction services enable<br />

access to relational databases and other legacy systems.<br />

The first three levels in the multitier architecture in Fig. 40.8 are provided by Netscape technologies<br />

and products, while the last levels—back-end services and other legacy systems—are accessed through<br />

standard Internet interfaces.<br />

IBM’s Architecture<br />

IBM has developed the Component Broker, which is Internet middleware for distributed objects [7].<br />

Component Broker is a software system that allows developers to build, run, and manage Web-enabled<br />

business objects, components, and applications. Component Broker consists of:<br />

• tools for building distributed and business objects, and applications,<br />

• a runtime that provides a distributed-object infrastructure on the middle tier, and<br />

• a system management functions for the distributed object runtime and its resources.<br />

Component Broker architecture, shown in Fig. 40.9, accepts inputs from any clients (Java or C++<br />

)<br />

transported via Internet InterORB Protocol, and ActiveX transported via a bridge. The object server<br />

consists of components that provide control, services, context, and connection resources.<br />

The Component Broker receives client requests through the CORBA-compliant object request broker<br />

(ORB). Object services are supplied through the CORBA common object services (COS). These services<br />

provide object transaction services, database services, system services, and object management functions,<br />

as illustrated in Fig. 40.9.<br />

Application adapters connect Component Broker object applications with existing software systems<br />

and applications.<br />

Microsoft’s Architecture<br />

Microsoft Internet architecture is a component-based architecture based on Windows DNA [14]. The<br />

heart of Windows DNA is the component object model (COM) that allows developers to build applications<br />

from binary software components at any tier of the application architecture. These components<br />

© 2002 by CRC Press LLC<br />

Presentation layer<br />

Dynamic HTML<br />

JavaScript<br />

Java<br />

RDF<br />

Plug-ins<br />

Web browser,<br />

other clients<br />

Internet, intranets,<br />

and extranets<br />

Open standards<br />

and protocols<br />

HTTP,IIOP,LDAP<br />

Content layer<br />

Java, C, C++<br />

JavaScript<br />

CGI<br />

Netscape’s multitier architecture for ASP.<br />

Application layer<br />

Java, C, C++<br />

JavaBeans<br />

CORBA<br />

DCOM<br />

Web server Application<br />

server<br />

Data and<br />

service layer<br />

Native languages<br />

Proprietary<br />

network services<br />

Legacy data<br />

and services<br />

Unix<br />

hosts<br />

Relational<br />

databases

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!