Overview

The separation of the Graphical User Interface (GUI) and database parts of JADE enables you to run JADE in a thin client mode. The JADE application logic is executed on the application server, and the only interaction with the presentation client is to notify the client of any GUI changes and to request information that is available only from that client.

The thin client mode of operation enables JADE to have a smaller operational "footprint" on the user workstation in terms of the required:

• Resource (memory and disk)

• Minimum workstation configuration

• LAN or WAN requirement is significantly reduced

Thin client operation moves most of the processing requirement from the client to the application server and reduces the amount of data that must be communicated when compared with a normal "fat" client. This enables you to run JADE applications over Intranets, dialup lines, and the Internet (World Wide Web).

Thin clients (or presentation clients) communicate with one or more application server processes, which in turn communicate with the JADE database on the server node.

Each application server and each presentation client is considered a JADE "seat". For JADE thin client operation, the application server executable (jadapp) can be run on the JADE database server or on other workstations.

The application server executable uses TCP/IP to listen for thin client connections.

The JADE presentation client executable (jade.exe) connects to the application server through TCP/IP. The application server executable runs a separate thread for each instance of a connected running application, to provide execution separation.

When initiating a thin client-based jade.exe executable with the newcopy command line argument set to false, execution is transferred to an existing jade.exe copy if that copy is running in thin client mode and it is connected to the same application server (the TCP address and TCP/IP port number must match), so that only one copy of jade.exe runs multiple applications connected to the same application server. If no other matching copy of jade.exe is running, execution continues as normal.

Remote printing, editing, exception dialogs, and so on, are handled by the application server sending these requests to the presentation client.

When operating in thin client mode, JADE retains initial form definitions previously displayed in a file so that they do not need to be sent again (thin client local caching). All dialogs (message boxes, exceptions, and so on) are invoked on the local workstation.

The jade.exe program is considered to be running in thin client mode if:

• Either appServer or appServerPort appears in the command line

• The path and server arguments do not appear in the command line

The JADE presentation client executable program jade.exe uses its own initialization file, located by default in the installation directory of jade.exe that is determined by the value of the JadeWorkDirectory parameter in the [JadeEnvironment] section of the JADE initialization file, unless you override this by specifying the ini parameter in the JADE presentation client command line. This initialization file contains parameters that affect the JADE presentation client local environment.

By default, the work file directory is created at the same level as the JADE binary directory (bin) and is named temp. For example, the directory is named c:\jade\temp if the JADE installation directory is c:\jade\bin. The JadeWorkDirectory parameter can specify an absolute path or a relative path (relative to the JADE HOME directory, which is c:\jade in the above example).

The presentation cache file is written into the directory defined by the value of the JadeWorkDirectory parameter unless the FormCacheFile parameter in the [JadeThinClient] section of the JADE initialization file specifies the location of the form cache file.

The presentation client automatic download process lock files are created in the directory specified by the JadeWorkDirectory parameter.

The automatic presentation client download log file is written to the location specified by the LogDirectory parameter in the [JadeLog] section of the JADE initialization file.

The only situations in which a file creation or update will occur within the JADE binary directory are as follows.

• If the JADE initialization file is located in the binary directory (the default action for a presentation client). You can avoid this by using the ini argument in the JADE presentation client command line to specify an alternative location on initiation of the presentation client.

• When the jaddinst executable program installs files downloaded by the JADE thin client automatic download facility.

For details about the:

• JADE Home directory, see "Specifying Arguments in the JADE Command Line", in Chapter 2 of the JADE Installation and Configuration Guide.

• For details about the JadeWorkDirectory parameter in the [JadeEnvironment] section of the JADE initialization file that is used to determine the directory in which work files are created, see the JADE Initialization File Reference.

• Directory locations (for example, program data and user data), see "Directory Locations", in Chapter 2 of the JADE Installation and Configuration Guide.

As the JADE automatic download installation program jaddinst.exe automatically uses the name of the presentation client executable defined in the PostInstallExe parameter of the [environment-type] environment‑specific section of the JADE initialization file if the value is jade or jade.exe, you can therefore use the same JADE initialization file parameter to re-initiate the presentation client, regardless of the presentation client that initiated the download.

Each presentation client environment supported by JADE has binary files specific to that environment that must be installed. The application server requires different sets of files to be available for downloading to presentation clients. The files must each reside in a different directory identified by the operating system version, and whether they are ANSI or Unicode files. For details about environment-type files, see Appendix B, "Upgrading Software on Presentation Clients".