Chapter 1 About Enterprise Application Server

How does Enterprise Application Server work?

A client executes a method in a component that resides on a Jaguar server. Typically, a component will execute some business logic or call a database and return data to the client. For example, Dynamo's tags and scripts can call Jaguar component methods and information can be returned from these methods to Dynamo. Dynamo sends this information in the form of dynamically generated HTML pages to the Web server, which sends the HTML pages to the Web client. The simplest way to execute a component method from Dynamo is to use Dynamo tags to call the method using MASP. A Jaguar server can execute a method as a stored procedure delivered in Transact-SQL or as a remote procedure call (RPC). You can also use Dynamo scripts to execute a component method using a Java or ActiveX object.

Also, a component created with AI for CICS or AI for Stored Procedures is executed by a client in exactly the same as any other Jaguar component. The following diagram shows:

The different ways that a component method can be invoked from Dynamo
An AI for CICS component executing a method on a COBOL program, an AI for Stored Procedures component executing a stored procedure, and an AI component, which has been developed using GoldenGate for EAServer, executes an SAP business object.

The above diagram illustrates these techniques to execute Jaguar component methods from Dynamo:

CreateObject method The ActiveX Proxy Automation Server (provided by Jaguar) and the proxy object (which is created at runtime as a surrogate object for the component on the Jaguar server) call the component method on the Jaguar server. The proxy object is instantiated from the type libraries and registration files that were generated by Jaguar Manager for a package of components.
java.CreateComponent method The stub object (which is created at runtime as a surrogate object for the component on the Jaguar server) calls the component method on the Jaguar server. The proxy object is instantiated from the Java stub classes and interface files that were generated by Jaguar Manager for a package of components.
SQL or FORMATTING tag, COMPONENT tag, or connection.CreateQuery or connection.CreateComponent methods A method as stored procedure call is made directly to the component method on the Jaguar server. The MASP feature in Jaguar supports this technique.

EAServer is a multitier distributed architecture that allows you to spread your Web site and OLTP application across many different machines. In the above diagram, the Web client requests a page from the Web server. The Web server requests the information from the Dynamo server, which in turn, uses the ActiveX Proxy Automation Server or a SQL command to call a component method on the Jaguar server. One component executes a method that makes a call to a CICS program--on the mainframe, the call is handled by the AI for CICS server, which, in turn, executes the CICS program. Another component uses JDBC to make a SQL query on an ASA database. Another component makes a JDBC call to the stored procedure on a database.