{--
JVM-Bridge -- bridge from FP languages and others to the Java VM
Copyright (C) 2001 Ashley Yakeley <ashley@semantic.org>

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
--}

-- four-space tabs
module Main where
	{
	import Foreign.JavaVM.Lib.Class_java_lang_System;
	import Foreign.JavaVM.Lib.Class_java_lang_String;
	import Foreign.JavaVM.Lib.Class_java_awt_Frame;
	import Foreign.JavaVM.Lib.Class_java_awt_Container;
	import Foreign.JavaVM.Lib.Class_java_awt_Component;
	import Foreign.JavaVM.Lib.Class_java_awt_Graphics;
	import ShowFrame_JVM;
	import Foreign.JavaVM;
	import Platform.JavaVM;
	import Data.Witness;


	-- define our own Component type
	data Class_MyComponent;
	instance IsJavaClassMarker Class_MyComponent where
		{
		cName Type = "org/semantic/jvmbridge/example/MyComponent";
		};
	instance SubJavaClassMarker Class_Jjava_awt_Canvas		Class_MyComponent;
	instance SubJavaClassMarker Class_Jjava_awt_Component	Class_MyComponent;
	instance SubJavaClassMarker Class_Jjava_lang_Object		Class_MyComponent;
	type MyComponent = ObjectRef Class_MyComponent;

	-- the paint method written out explicitly
	paintMethod :: MyComponent -> (JGraphics) -> JVM Jvoid;
	paintMethod frame (graphics) = do
		{
		width <- getWidth_JComponent frame ();
		height <- getHeight_JComponent frame ();
		drawOval_JGraphics_Jint_Jint_Jint_Jint graphics (0,0,width,height);
		};

	main :: IO ();
	main = run (runJVM (do
		{
		loader	<- getStandardClassLoader;									-- defineCallbackClass needs this
		hcClass <- defineCallbackClass loader (Type :: Type MyComponent) (Type :: Type Jjava_awt_Canvas)
			[]																-- no interfaces
			[]																-- no constructor arguments other than methodvals
			[MkMemberNameType												-- just one overridden method
				"paint"														-- called 'paint'
				(MkFunctionType
					[MkObjectType "java/awt/Graphics"]						-- argument list is just a java.awt.Graphics
					MkVoidType												-- void return type
				)
			]
			;

		paintMethodVal	<- makeCallback paintMethod;						-- convert the method to a 'val' that can be passed to a constructor

		(myComponent :: MyComponent) <- newObject hcClass (paintMethodVal);	-- create a new MyComponent

		title <- new_JString_ArrayJchar ("Haskell / Java VM" :: JavaString);-- title String for the frame
		frame <- new_JFrame_JString (title);								-- create a new Frame
		add_JContainer_JComponent frame (myComponent);						-- put the MyComponent in the Frame
		setVisible_JComponent_Jboolean frame True;							-- show the Frame

		putStrLn ("Yielding to other JVM threads for 30s...");		-- tell user what's going on
		withProcsThread (do
			{
			startTime <- currentTimeMillis_JSystem ();
			yieldLoop (do													-- yields to other Java and Haskell threads
				{
				curTime <- currentTimeMillis_JSystem ();
				return (curTime < startTime + 30000);						-- 30s yet?
				});
			});
		}));
	}