Question

Hi guys I have a problem that makes me really confused, I have ‘writeMethod’ which is a type of Method class, ‘dpv’ which is a type of a propertyDescriptor, i retrieved the writeMethod of the object by getWriteMethod(), now my problem is how to set ‘writeMethod’ to write on a property of an object (e.g. JLabel, JButton) here is my code :

 if(dpv.getPropertyType().isPrimitive() 
         || dpv.getPropertyType().isInstance("Integer") )
        {
            Method writeMethod = dpv.getWriteMethod();

            //setWriteMethod(writeMethod);<---------- Not sure about this part (doesn't work)

            System.out.println(writeMethod);
            PropertyValue.setEnabled(true);
            SetButton.setEnabled(true);
        }
        else{

            PropertyValue.setEnabled(false);
            SetButton.setEnabled(false);
        }

Thanks for your help guys

Answer 1

To use the method to write the propery, you have to invoke it. Simple properties take a single value – the value of the property, so you invoke the method with a single argument. The following code sets the property on a button to the value 42:

Method writeMethod = dpv.getWriteMethod();    
JButton button = ...; // the target to write to

try
{
   writeMethod.invoke(button, 42);
}
catch (IllegalAccessException ex)
{
  // handle these as appropriate
}
catch (IllegalArgumentException ex)
{
}
catch (InvocationTargetException ex)
{
}

It’s unlikely you have them, but if the property is the seldom-used indexed property type, then you need to use the method like this:

writeMethod.invoke(target, index, propertyValue);

This corresponds to the setter method

setIndexProperty(int index, PropertyType value);