firstclause('This is the first clause of this file'). 

:- package(gui).
:- package(guibuilder).
:- package(guievent).

main(Applet,_) :-
	gui(Applet, gridbag, [
			fill=both, weightx=1.0, weighty=1.0,
				button(_, 'code base') **
						action(get_codebase(Applet, Info)),
				button(_, 'document base') **
						action(get_documentbase(Applet, Info)),
			width=remainder,
				button(_, 'server text file') **
						action(get_serverfile(Applet, Info)),
			weightx=0.0,
			width=remainder, height=1,
				label(Info, '', center)
		]).

get_codebase(Applet, Info) :-
	applet_getCodeBase(Applet, Codebase),
	url_toExternalForm(Codebase, Name),
	label_setText(Info, Name).

get_documentbase(Applet, Info) :-
	applet_getDocumentBase(Applet, Documentbase),
	url_toExternalForm(Documentbase, Name),
	label_setText(Info, Name).

get_serverfile(Applet, Info) :-
	applet_getCodeBase(Applet, Base),
	url_toExternalForm(Base, BaseName),
	atom_concat(BaseName,'ExamplePrograms/MinervaFeatures/FileFromServer/',Name),
	atom_concat(Name, 'location.min', Url),
	(
	 lookup_serverfile(Url,Clause) ->
		functor(Clause,Functor,Arity),
		atom_number(ArityAtom,Arity),
		atom_concat(Functor,ArityAtom,Text)
	;
	 atom_concat('not found - Check URL: ',Url,Text)
	),
	label_setText(Info, Text).

lookup_serverfile(Url, Clause) :-
	catch(read_first_clause(Url, Clause), _, fail), !.

read_first_clause(Url, Clause) :-
	write(open(Url,read,Stream,[url,text,buffered])),nl,
	open(Url, read, Stream,[url,text,buffered]),
	read(Stream,Clause),
	close(Stream).