state-of-the-lambda syntax for non-SAM types such as WindowAdapter.

[Peter Levart]

On Thursday, July 08, 2010 05:11:39 am Reinier Zwitserloot wrote:
> An idea:
> 
> The state-of-the-lambda document allows lambda literals to be explicitly
> typed:
> 
> Comparator<String> {a, b -> return a.length() - b.length()};
> 
> 
> What if one could also append the method to this? Then these closures can
> extend to non-SAM types:
> 
> frame.addWindowListener(WindowAdapter.windowClosed {e -> .... });
> 
> Just a thought.
> 
> --Reinier Zwitserloot

You don't need special syntax for that. For example:

public class WindowAdapters
{
    interface Fn
    {
        void invoke(WindowEvent e);
    }

    public static WindowAdapter windowOpened(final Fn fn)
    {
        return new WindowAdapter()
        {
            @Override
            public void windowOpened(WindowEvent e)
            {
                fn.invoke(e);
            }
        };
    }

    public static WindowAdapter windowClosed(final Fn fn)
    {
        return new WindowAdapter()
        {
            @Override
            public void windowClosed(WindowEvent e)
            {
                fn.invoke(e);
            }
        };
    }

    // etc...
}


// and with an additional pair of parens you can write:

frame.addWindowListener(WindowAdapters.windowClosed({e -> .... }));


Regards, Peter