Introducing the GAS and JGAS

The Genero Application Server (GAS) is an engine that plugs in to a Web server for the purpose of delivering Genero Web applications and services. The Genero Application Server for Java (JGAS) is designed to run your applications on the Java EE servlet. A general knowledge of how they operate can be helpful in testing and deploying Web applications.

The GAS manages the Genero Browser Client or the Genero Desktop Client application requirements of the Web server. It uses dispatchers and proxies to optimize reliability, performance, and integration in Web servers. The dispatcher handles the GAS configuration and keeps a persistent session table of all proxies for the Dynamic Virtual Machine (DVM) or runtime it starts.

In development environments, it is possible to exclude the Web Server and run applications as standalone on the GAS. The httpdispatch is the standalone dispatcher used to connect to applications from the local machine.

From version 3.10 onwards the JGAS, a GAS written in Java, can be packaged in a Java Web Archive (.war) file. Applications can be run as standalone without the need for a separate GAS installation or a Java Enterprise Edition (Java EE) server.

Gas features

These features are common to both the GAS and JGAS:

  • Connections between the DVM and the front-end are handled by the GAS in a one-to-one relationship. The GAS manages an application session and provides a debugging and logging mechanism for dispatchers and proxies. Session information is saved in case the Web server fails, which allows for the application to continue when the server restarts.
  • The GAS features a command line tool (gasadmin) that can perform several administrative tasks. This includes stopping a DVM (if required) without affecting any other applications that are running concurrently on the server.
  • The GAS supports a timeout feature called AUTO_LOGOUT which can be configured to log out a user and display a log out page after a specified time of user inactivity on a GUI client.
  • The GAS allows for user authorization and authentication to be implemented via delegation and single sign-on.
  • A GAS installation is required if you provide Genero Web Services (GWS) servers. The GAS manages a pool of connections for clients accessing your Web services.
  • Applications that are deployed to run on a GAS on a Web server can be easily configured based on default application configurations and resources defined in the GAS configuration file as.xcf.

The GAS is usually installed on the same machine where the Genero BDL runtime is installed. For more information, refer to the Genero Application Server User Guide.

JGAS features

The JGAS is an implementation of the GAS that is packaged with the FGLGWS product. It performs the same functions as the GAS and can be used for the development, testing, and deployment of applications.

The JGAS differs from the standard GAS in the way it uses Web server resources such as sockets and memory in the handling of HTTP communication between the DVM and the front-end. Processes are similar except that proxies are not used between the DVM and the dispatcher. HTTP requests are processed internally and one socket per DVM is all that is required to maintain the communication. For more information see the JGAS overview page in Genero Application Server for Java User Guide.

Using the JGAS

The fglgar tool provides you with access to the JGAS and a means to package, deploy, and run applications.

The fglgar war command provides the ability to package a Genero Archive (.gar) file with your applications, and to include the JGAS implementation, the Genero Browser Client, and any additional files in a Java Web Archive (.war) file. The Java Web Archive (.war) file can be deployed in any existing Java Enterprise Edition container such as Apache Tomcat®, Jetty, or Glassfish and the applications can be run in a browser.