Applications

1. Summary

The applications node is the root node for all applications. Each configured application in the Dataphor Server will have an application node that is a child of this node. The root applications node simply allows for the addition of a new application, as well as a refresh command for refreshing the list of applications.

Each application node exposes functionality for managing the properties of the application, deleting the application, and starting the application.

A Dataphor application consists of a set of required libraries, a starting document, and various configuration settings which control general behavior characteristics of the application and the Frontend Clients running it.

2. Creating a New Application

By right-clicking on the applications node and selecting the Add…​ command, users can create a new application. The following screen capture displays the application edit form:

Editing a Dataphor Explorer application

The Description is the user-visible description of the application. When a Frontend Client connects to a Dataphor Server, the descriptions of the available applications are displayed, and the user selects which application to run.

The Start Document is the entry point for the application. It is the first user interface that the user running the application will see. All the functionality required by the application should be available from this starting point. Once the user closes this main form, the application is closed and the Frontend Client shuts down.

Another way to create an application is by simply dragging a Dataphor Form document from the documents node of a library, or a Table node from the Tables node, and dropping it on the applications node. The application edit interface will be displayed with the Start Document set to the document expression required to load the form, or browse the table, and the library it is in as a required library of the application.

2.1. Windows Client Settings

Applications can also configure certain general settings about the behavior of the Microsoft Windows Frontend Client. These settings are available from the Extensions | Windows Client Application Settings command. The following screen capture shows the result of selecting this command:

Editing Dataphor Explorer Windows Client Settings

The Theme Document is a D4 expression that specifies a theme document. Windows themes allow the look and feel of the Windows Client to be changed. For more information on Windows themes, see the Presentation Layer part of the Dataphor Developer’s Guide.

The Default Form Icon Image is a D4 expression that specifies an icon image to be used as the icon for all the forms in the application.

Document Cache SizeThe Document Cache Size controls the size of the document caching system built into the Windows Client. Whenever a document is requested in the Frontend Client, the cache is checked to see if an appropriate version of the document has already been downloaded to the client. If so, that version of the document is used rather than requesting it from the server.

The default size for the document cache is 800 documents. Setting the cache size to 0 disables the cache. Each application creates and maintains a different document cache.

Image Cache SizeThe Image Cache Size controls the size of the image caching system built into the Windows Client. Whenever an image is requested in the Frontend Client, the cache is checked to see if the image has already been downloaded to the client. If so, that image is used rather than requesting it from the server. The default size for this cache is 60 images. Setting the cache size to 0 disables the cache.

The difference between the two caches is that the document cache still requires a network round-trip. The document request is still made, but the version of the document in the cache is sent with the document request. If the version of the document on the server is the same, the server does not send the document with the response, and the client retrieves the document from the cache.

In the image cache, no network round trip is required. If the image has already been downloaded, it will be used. Because this cache is not transparent (i.e. changes made to images on the server that have already been requested by the client will not be re-requested), this cache does not survive the application session. When the application is re-started, the image cache will be rebuilt as images are downloaded.

The document cache, on the other hand, is completely transparent and does survive the application session. When the application is re-started, the same document cache is used from the last application session.

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