Lesson 6: Create the appropriate Java classes to handle the verification and validation

In the previous lessons you configured the extension points; now you create the Java™ classes that are needed to handle the validation of the parameters and actions.

About this task

Tip: As you create these Java classes, they will each have to implement or extend certain interfaces or classes respectively. To determine what classes or interfaces need to be included, you can right-click on the extension in the Plug-in Editor and select Show Description. The description of the extension will open in the editor. If you scroll down to the API Information heading, you find the classes or interfaces the class needs to use in conjunction with the extension point.


  1. Start by creating the class that is used with the parameterValidator extension point. This class is responsible for checking to make sure the value that is entered into the value parameter follows the specifications that are outlined in this sample. In the Package Explorer view, right click the com.ibm.carma.plugin.howto plug-in project, and select New > Package.
  2. In the New Java Package dialog box that opens, enter com.ibm.carma.plugin.howto.action as the name for the package. Click Finish. You should see the package that is created under your Eclipse plug-in project.
  3. Now, right click the com.ibm.carma.plugin.howto.action package you created, and select New > Class. The New Java Class dialog box opens.
  4. Enter ValueParamValidator in the Name text field.
  5. To the right of the Interfaces click the Add button. In the Implemented Interfaces Selection dialog box that opens, filter for the interface IParameterValidator. Click Finish to close the New Java Class dialog box and open the class in the editor.
  6. Now, you create the second Java class that is responsible for handling the verification of the HowTo action. Right click the com.ibm.carma.plugin.howto.action package and select New > Java Class.
  7. In the New Java Class dialog box that opens enter the name of the class to be, ActionValidator and add the interface IActionValidator. Click Finish to close the dialog box and create the class.
  8. Finally, create the last Java class following the above steps and by defining a name of CheckboxOptionControl. Click the Browse button to the right of the Superclass text field. The Superclass Selection Dialog Box should open. Filter for the class, AbstractCustomParameterControl, select it, and click OK.
  9. Click Finish to close the New Java Class dialog box and open the class in the editor.


You have now created the classes that handle the verification features offered by the extension points.