All tasks may be executed synchronously or asynchronously depending on the process requirement. A Task object contains the definitions of and source control references for the input parameters, the destination control references for its results, and the operations that it must perform.

In the workout example, the SOAP wizard created a Search Task to execute the appropriate Web service for retrieving the workout definition. When the submit button is clicked, the associated onClick event executes the Task to retrieve the data. The resulting XML document is displayed in the output textbox.

While tasks handle data associated with the request/response of service calls, a Request Broker object handles the details of the communications process. Three broker types may be used in WebFace: Local, SOAP, and HTTP. The Local broker may only be used in conjunction with an Open Task to retrieve a window definition from the local machine. The remaining tasks may be used to execute remote services either via SOAP calls or HTTP calls.

In the workout example, the result of the Web service call is an XML document that is displayed in a text box. In order to work with the data, however, a more sophisticated view of the information, such as a grid, must be presented to the user. To accommodate a grid display, a DataSet must be defined to hold the information. Figure 2 shows the DataSet Editor dialog in WebFace Studio. This allows the developer to specify the columns and rows for the data grid. Constraints may be placed on the data, including data types, whether a value in a column is required, or its nullability. Once the DataSet is defined, a DataController is created to link the DataSet to the display grid.

 

To populate the new DataSet, the information from the XML document produced by the Web service must be mapped appropriately. Recall that WebFace windows and their controls are themselves XML documents. Therefore, an XSL stylesheet may be used to transform the result of the Web service into the appropriate DataSet object (note that parameters for a request are also transformed via XSL stylesheets from their source DataSets into the service call). To assign a stylesheet to perform the transformation, the task is edited to include an xsltReplyTranslator that points to the desired XSL stylesheet. Figure 3 is a new window created in WebFace Studio that leverages the communications components and input fields created by the SOAP Wizard, but with the output transformed by an XSL stylesheet to fill a data grid.

 

As mentioned earlier, WebFace applications are event driven. Event handlers and all supporting code are written using JavaScript. In the WebFace Studio IDE, the developer may switch to the source view of the window to reveal the WAML document. From here, the CDATA element of the customCode tag may be edited to include any supporting JavaScript. All controls created are accessible as objects from the JavaScript code and may be manipulated or inspected at runtime. To wire an individual event handler to a control, the function name is assigned to the desired event in the properties editor for the control.

Deploying Applications
WebFace Studio provides a wizard to deploy applications for testing. The wizard may be used to deploy locally or remotely to a server. The local deployment simply copies the application files to a local directory on the developer's machine. Internet Explorer may be pointed to this directory using a file URL to launch the application. For server deployments, the destination machine must provide FTP write access. At deploy time, the application's configuration files are updated to reflect the runtime environment.

Summary
WebFace and WebFace Studio from Vultus provide the means to deliver rich, Windows-like user interfaces for Web services to a browser. By leveraging XML, HTML, and JavaScript they negate the need for browser refreshes when executing service calls and manipulating data. It does require some time to become comfortable with the development environment and the relationship between the various controls and components, but once acclimated, application development is relatively straightforward. For Internet Explorer-based applications, the WebFace product suite from Vultus is a good alternative.

Company Info
Vultus, Inc.
355 South 520 West, Suite 150
Lindon, UT 84042

SALES
sales@vultus.com
801.852.0880