Use data driven adapters (DDAs) in Unified Service Desk
Data-driven adapters (DDAs) are the adapters leveraged generally by the Hosted Application Toolkit (HAT). These adapters are generic assemblies that handle only the interaction with the UI and do not contain business processes. The Unified Service Desk SDK ships with a DDA that provides a common set of functions that allows you to host and access a wide range of applications. However, you might require additional functionality depending on the type of application. There are various ways of extending the existing functionality, such as creating a new DDA (and using it in a composite DDA with outer DDAs) and extending an existing DDA.
In This Section
Using DDAs in custom application adapters
Types of Data Driven Adapters
There are four types of DDAs:
Creating a DDA
You can create a new DDA by simply inheriting the DataDrivenAdapterBase class.
The class has the constructor which can be overloaded.
Extending an existing DDA
In the previous section we saw how to create a DDA. However, if your customization is nominal, you can use the existing DDA and extend it as per requirements.
You can use the following classes to extend the existing UII DDAs:
WinDataDrivenAdapter: Creates an adapter based on the WinDDA.
WebDataDrivenAdapter: Creates an adapter based on the WebDDA.
JavaDataDrivenAdapter: Creates an adapter based on the JavaDDA.
UIADataDrivenAdapter: Creates an adapter based on the UIADDA.
All the preceding classes derive from DataDrivenAdapterBase class.
Bindings
A data-driven adapter uses data, named the bindings, to define the way that it identifies a UI component of a hosted application. For example, the bindings may consist of Document Object Model (DOM) paths for describing elements on a webpage. The following example shows an application initialization string with an embedded DDA binding sub-tree. This is a general example, but it indicates the pattern used to implement Acc controls in Windows bindings.
Note
Some of the configuration parameters have been removed for clarity.
<initstring>
<interopAssembly>
<URL>path to executable</URL>
<Arguments>test argument</Arguments>
<WorkingDirectory>c:\</WorkingDirectory>
<hostInside/>
</interopAssembly>
<!—- notice there is no custom application adapter specified here-->
<displayGroup>None</displayGroup>
<optimumSize x="800" y="600"/>
<minimumSize x="640" y="480"/>
<DataDrivenAdapterBindings>
<Type>typeName, assemblyName</Type>
<Controls>
<AccControl name="combobox1">
<Path>
<FindWindow>
<ControlID>1003</ControlID>
</FindWindow>
</Path>
</AccControl>
</Controls>
</DataDrivenAdapterBindings>
</initstring>
If you are using the HAT Software Factory, it will create the InitString. The application can then be deployed to the server from the software factory.
If you are directly adding a hosted application using the Admin UI, you do not need to create the complete InitString. You only need to specify the <DataDrivenAdapterBindings> section and add it to the Automation Xml tab.
Using DDAs in custom application adapters
Although DDAs were initially conceived to support automations within the Hosted Application Toolkit (HAT), they can also be used by custom adapters to achieve useful results. The following code sample, taken from a custom adapter, illustrates how custom adapters can use DDAs, and illustrates the general advantages of DDAs. As the sample illustrates, the use of DDAs allows a separation of code and configuration information.
DataDrivenAdapter Dda;
public override bool Initialize()
{
Dda=DataDrivenAdapter.CreateInstance(ApplicationInitString,ApplicationObject);
return (Dda != null);
}
public override bool DoAction(Action action, ref string data)
{
if (action.Name == "AddToHistory")
{
Dda.ExecuteControlAction("combobox1");
Dda.SetControlValue("textbox1", data);
Dda.ExecuteControlAction("button1");
}
}
The DDA configuration, which is embedded in the application's InitString, is XML, as in the following example.
<DataDrivenAdapterBindings>
<Type> Microsoft.UII.HostedApplicationToolkit.DataDrivenAdapter.WinDataDrivenAdapter, Microsoft.UII.HostedApplicationToolkit.DataDrivenAdapter</Type>
<Controls>
<AccControl name="combobox1">
<Path>
<FindWindow>
<ControlID>1003</ControlID>
</FindWindow>
</Path>
</AccControl>
<AccControl name="textbox1">
<Path>
<FindWindow>
<ControlID>1001</ControlID>
</FindWindow>
</Path>
</AccControl>
<AccControl name="button1">
<Path>
<FindWindow>
<ControlID>1002</ControlID>
</FindWindow>
</Path>
</AccControl>
</Controls>
</DataDrivenAdapterBindings>
The <Type/> element directs UII to dynamically instantiate the type specified in type, assembly format, thus allowing custom DDAs to be loaded and used. The <Controls/> element contains the list of configured controls, specified in a manner required by the loaded DDA.