MacFrameDecorator.java

package com.vizor.unreal.platform.mac;

import com.vizor.unreal.platform.FrameDecorator;

import javax.swing.ImageIcon;
import java.awt.Image;
import java.lang.invoke.MethodHandle;
import java.net.URL;

import static java.lang.invoke.MethodHandles.lookup;
import static java.lang.invoke.MethodType.methodType;

public class MacFrameDecorator extends FrameDecorator
{
    // Root application class
    private final Object application;

    // Methods:
    private final MethodHandle setDockIconImage;

    public MacFrameDecorator()
    {
        try {
            final Class<?> applicationClass = Class.forName("com.apple.eawt.Application");
            application = applicationClass.getMethod("getApplication").invoke(null);

            // setDockIconImage method handle
            setDockIconImage = lookup().findVirtual(applicationClass, "setDockIconImage",
                    methodType(void.class, Image.class));
        }
        catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }

    @Override
    protected void setApplicationIconImpl(URL iconUrl)
    {
        final Image image = new ImageIcon(iconUrl).getImage();
        try {
            setDockIconImage.invoke(application, image);
        }
        catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }
}