ArchitectureThe open standards architecture Jcorporate
utilizes is extensible and scalable with
and capable of parallel servers for rapidly
assembling additional applications services,
and the ability to distribute those services
to a broad network of users, customers and
partners. |
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Multi-tier ArchitectureJcorporate uses a true multi-tier Internet/Intranet
architecture. This affords the user many
advantages. Jcorporate uses a true multi-tier Internet/Intranet architecture. This affords the user many advantages. Each section also describes the software requirements for Jcorporate components to run; and further how these components contribute to the reusability and extensibility of the components for modifications. The Servlet Run-time EnvironmentA servlet is a Java class and therefore needs to be executed in a Java VM by a service we call a servlet engine. The servlet engine loads the servlet class the first time the servlet is requested, or optionally already when the servlet engine is started. The servlet then stays loaded to handle multiple requests until it is explicitly unloaded or the servlet engine is shut down.A Servlet-based solution is a standards-based
solution which scales to what you need tomorrow.
Web/Application ServersThe top tier is composed of your company’s various application servers (back-end). This collection may be a heterogeneous mix of environments, such as UNIX, NT, VMS, MVS, or AS/400. These systems are unmodified and kept intact. Java 2 (JDK 1.2 recommended, or at least 1.1.7) support is only necessary on the server side with Jcorporate. Jcorporate supports any web server capable of working with a servlet runner tool, either Sun’s default servlet runner or a commercial servlet runner such as JRun. By example software requirements for a Web server include any of the following:
Some Web servers, such as Sun's Java Web Server (JWS), W3C's Jigsaw and Gefion Software's LiteWebServer (LWS) are implemented in Java and have a built-in servlet engine. Other Web servers, such as Netscape's Enterprise Server, Microsoft's Internet Information Server (IIS) and the Apache Group's Apache, require a servlet engine add-on module. The add-on intercepts all requests for servlets, executes them and returns the response through the Web server to the client. Examples of servlet engine add-ons are Gefion Software's WAICoolRunner, IBM's WebSphere, Live Software's JRun and New Atlanta's ServletExec. Application servers with load balancing and sophisticated administration features, like ATG's Dynamo and NetDynamics, support Servlets as well. The Expresso Framework also supports any commercial EJB server as the back-end server, to enable server-side logic to be coded using the Enterprise JavaBean standard. Servlets act as the user-interface, and the application framework fills in the gap between the servlets and the application logic being supplied by the EJB's. Application Framework TierThe next tier is the Jcorporate Application Framework, which uses many different means to communicate with the web servers. At the same time, it serves as a web agent to allow easy access to the back-end applications by way of the intranet. The application framework is accessed via the standard "servlet" capability of Java, requiring nothing special of the browser client. Database TierAnother tier in the mix is the database, where i.e. report definitions are contained, and, optionally, a database where data warehouse data is kept for reports to draw from. The user never interacts directly with this database, preventing any potential security issues from arising. Since Servlets can use all Java APIs, they are easy to integrate with other parts of the IT infrastructure. All major databases can be accessed through JDBC, directory services through JNDI, and advanced distributed services through RMI and Java IDL. Jcorporate supports any JDBC-supported database. We have tested with a number of database engines including:
Client TierThe last tier contains the clients connected via the Internet/Intranet. Using a web browser, they can run or schedule programs that currently exist on their company’s application servers. i.e. the report server processes their requests and communicates with the application servers. No client-side Java support required. Jcorporate supports any current web browser supporting thee HTML Forms capability including:
System RequirementsPlease see the system requirements page for Expresso and the Jcorporate components built using Expresso. |
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Last Modified: 12-Dec-01
