Lesson 9: Create the code for the CheckboxOptionControl class

The CheckboxOptionControl class changes the CARMA default text field to a checkbox on the Option parameter. Since this parameter is a yes or no parameter, a checkbox is more convenient for the user.

1. In the Package Explorer view, open the CheckboxOptionControl class you created by navigating com.ibm.carma.plugin.howto > src > com.ibm.carma.plugin.howto.action and double-clicking on the class.
2. You will first add the checkbox button object as instance data for the class. This allows the checkbox button and all its metadata to be available to the CheckboxOptionControl class. Add the following line of code: Button theButton;
3. Next, you override the createControl method to create the checkbox button and return it instead of the default text field. The following pseudocode demonstrates what you want this method to do:

   Create theButton with the checkbox style
   Give the theButton some text
   Return the theButton

   Use the following sample code to override this method:

   /* Create a checkbox for the yes/no option */
   public Control createControl(Composite parent, 
                                RepositoryManager repositoryManager,
                                Parameter param, 
                                Action action,
                                CustomActionAccepter custActionAccepter,
                                Object defaultValue) 
   {
      theButton = new Button(parent, SWT.CHECK);
      theButton.setText("Check me!");
      return theButton;
   }

4. Now, you override the getValue method. This method returns the value of the parameters. Since you are using a checkbox instead of a text field, the code you write will have to translate the check or unchecked status of the checkbox into the expected string format. The following pseudocode demonstrates this:

   if the checkbox is checked
   	return "Y" for yes
   else
   	return "N" for no

   Use the following sample code to override this method:

   public Object getValue() 	{
   		if(theButton.getSelection())
   			return "Y";
   		else
   			return "N";
   	}

5. The last method that you need to override is the isUsingDefaultLabel method. If set to false, this method will not display the default label that you provided when you added the parameter to the RAM. If set to true, then the label is displayed like normal. For this sample, the code will use the default label.
   Use the following sample code to override the method:

   public boolean isUsingDefaultLabel()
   {
      return true;
   }

6. Finally, you need to ensure that all required imports are listed. Add any of the following import statements that are not listed in your class:

   import org.eclipse.swt.SWT;
   import org.eclipse.swt.widgets.*;
   
   import com.ibm.carma.model.*;
   
   import com.ibm.carma.ui.action.custom.AbstractCustomParameterControl;

7. Save the source and debug any errors.

package com.ibm.carma.plugin.howto.action;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.*;

import com.ibm.carma.model.*;

import com.ibm.carma.ui.action.custom.AbstractCustomParameterControl;

public class CheckboxOptionAction extends AbstractCustomParameterControl {
   //Add the button to the instance data
   Button theButton;
   
   /* Create a checkbox for the yes/no option */
   public Control createControl(Composite parent, 
                                RepositoryManager repositoryManager,
                                Parameter param, 
                                Action action, 
                                CustomActionAccepter customActionAccepter, 
                                Object defaultValue) 	{
      theButton = new Button(parent, SWT.CHECK);
      theButton.setText("Check me!");
      return theButton;
   }

   @Override
   public Object getValue() 	{
      if(theButton.getSelection())
	      return "Y";
      else
         return "N";
   }

   @Override 
   public boolean isUsingDefaultLabel() 	{
      return true;
   }
}