[2338] in java-interest
java-interest-digest V1 #195
daemon@ATHENA.MIT.EDU (owner-java-interest-digest@java.su)
Fri Sep 29 10:59:22 1995
From: owner-java-interest-digest@java.sun.com
Date: Thu, 28 Sep 1995 07:58:42 -0700
To: java-interest-digest@java.sun.com
Reply-To: java-interest@java.sun.com
java-interest-digest Thursday, 28 September 1995 Volume 01 : Number 195
In this issue:
java-interest-digest V1 #188
Q: communicate with applets(applet <---> applet)
Re: hideing/showing awt components
Re: Spare CPU cycles
Re: [Q] - "javac: invalid atgument: noclobber"
Thoughts on the multiplication of files
Ideal Java machine?
Re: Socket Communication
How do I do a getenv under the pre-beta JDK?
----------------------------------------------------------------------
From: owner-java-interest-digest@java.sun.com
Date: Tue, 26 Sep 1995 08:53:08 -0700
Subject: java-interest-digest V1 #188
java-interest-digest Tuesday, 26 September 1995 Volume 01 : Number 188
In this issue:
[none]
Re: Consoles and repaints
Re: throws declataration in Java/beta
Re: Getting nowhere with JDK
Re: native library path
Re: Public class == File Name = Why?
Re: mo betta questions
Re: Function keys
Re: GridLayout weirdness...
Re: Consoles and repaints
Re: Dynamic Loading of Classes
?Java interface to Oracle or other DB
Re: AWT instance variables
Re: [Q]: How to draw a point (new api)?
Q: java profiling on WiNT with alpha3
Re: awt question
Win95 JDK available?
GUI design
putmsg multiply defined in java VM (JDK) (fwd)
Re: interfaces are NO substitution for method pointers
Re: host handles & the like
Placing applet in HTML page
RE: Function keys
Re: mo betta questions
Re: Placing applet in HTML page
calling native C/C++ : portability
hideing/showing awt components
- ----------------------------------------------------------------------
From: Joseph Jones <jones@bluesky.iwn.com>
Date: Mon, 25 Sep 1995 23:44:47 -0700
Subject: [none]
I've written a small Rectangle class, and in so doing I've come across =
anumber of errors (mostly due to the fact that I am new to java).
First Error: I wrote my rectangle class in the .java file of another =
program. This compiled fine, but when I loaded the html file that had =
the reference to my program, I received an access violation stating =
that my program had attempted to read the Rect3D.class. I was puzzled, =
as this is exactly what I thought it should be doing?
Second Error(actually user gripe): I pulled out the Rect3D class and, =
after much hair pulling, managed to create it in a new directory under =
the \hotjava\classes directory. After even more hair pulling, and =
checking the mailing list archives, I found out that to declare an array =
of my Rect3D class, I have to do the following:
Rect3D pane[] =3D new Rect3D[4];
for (int i =3D 0; i < 4; i++)
pane[i] =3D new Rect3D();
It seems a little ugly having to new twice just to get an array of my =
class. Why is this? (The mailing list article Iread stated that the =
first new was just creating an array of pointers of my class type, and =
that the second new was needed to create objects of my class to store in =
the array. Seems a bit kludgey to me.)
Thanx,
Joseph Jones
P.S. When will the Beta environment for Win32 be out. I've got the =
Alpha3 releases and am very impressed with the language as a whole. =
Unfortunately, its quit hard to develop applets when the HotJava browser =
just up and dies for no reason.
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 11:01:30 -0800 (PDT)
Subject: Re: Consoles and repaints
Hi Elliotte,
> Two questions that aren't apparently related:
>
> 1. In HotJava alpha 2 for NTand apparently on Solaris
> there was always a console window open to receive the results of
> commands like System.out.println and error messages. That apears to
> have gone away in HotJava alpha 3 for NT. Is there a way to get it
> back?
I don't think so. The output goes to a log file on the PC.
> 2. Is there a method I can call to force an applet to repaint?
Yes. It is called repaint!
Have fun,
Arthur van Hoff
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 10:14:55 -0800 (PDT)
Subject: Re: throws declataration in Java/beta
Hi Paul,
> Can someone please confirm the following:
>
> In beta Java, if object A extends object B, and both implement method
> foo(), A.foo() *cannot* throw exception X unless B.foo() also
> throws X. If you declare that A.foo() throws X, the compiler
> will complain that B doesn't also throw X.
>
> This means that you can NEVER throw an exception from a
> toString() method because Object.toString() doesn't throw
> any exceptions.
>
> Is this correct?
Yes. The toString() method declaration is a guarantee. That means that
you can't break it later on and throw an exception anyway.
Have fun,
Arthur van Hoff
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 11:57:06 -0800 (PDT)
Subject: Re: Getting nowhere with JDK
Hi,
> This may seem like a silly question, but WHAT am I doing wrong?
Nothing. It is a bug. Try setting your DISPLAY environment variable.
> I am not normally one for following instructions etc. but this time I did
> and <bang> nothing!
>
> Downloaded JDK onto SPARC 10, loadsa disk and memory - a o k.
> Read the README .... always a un-nerving experience!
> Added ~/java/bin to my path.
> Tries appletviewer demo/TicTacToe/example1.html (Or whatever the path)
>
> and ...
>
> <BANG>
>
> skynet% appletviewer example1.html
> SIGSEGV 11* segmentation violation
> si_signo [11]: SIGSERV 11* segmentation violation
> si_errno [0]: Error 0
> si_code [1]: SEBV_ACCERR [addr:0xc]
>
> ... now not being an expert. I would say that was BAD.
> What did I say? Did I not ask it nicely?
>
> The machine is running Solaris 2.4, so thats not a prob. The
> only thing that I can think of is that I am trying to redirect
> the display! but thats just silly - isn't it?
Have fun,
Arthur van Hoff
- ------------------------------
From: Larry Reu <larryr@CyberGate.COM>
Date: Tue, 26 Sep 1995 01:00:06 -0700 (PDT)
Subject: Re: native library path
>
> Question: what is the Windows NT equivalent to the
> LD_LIBRARY_PATH environment variable in UNIX.
>
WinNT (and Win95 for that matter) follow the PATH env var to
locate DLL's -- Dynamically Linked Libraries similar to UNIX so's.
......larry
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 11:18:46 -0800 (PDT)
Subject: Re: Public class == File Name = Why?
Hi Anders,
> In the current (Alpha3) language specification there is a line that says
> that there can be max 1 public class or interface per CU (compilation Unit).
> Also there is a compiler warning if the source file differs from the name
> of the public class. The reason behind all this seems to be that the
> compiler can automatically invoke source files for external classes.
>
> My question is: Is Java the only computer language where the source file
> name is a part of the language grammar? Should not be there IMO.
This is merely an artifact of the compiler implementation. A better
development environment would not have this requirement. It is merely
a work around so that the compiler can find classes without requiring
you to import them explicitly.
> Assuming that I am correct this is what I would like to see in the Beta
> release:
> 1. Delete the requirement that multiple public classes cannot be in the same
> CU. It is nice to put public classes and interfaces that belong together in
> the same file. BTW, It works just fine in A3. You get a warning but thats
> all. In the planned Beta all warnings have been taken away so this pratice
> is soon broken.
I wish it was that easy. How does the compiler find public classes if they
can be burried in any .java file?
> 2. As the auto-source-search feature *may* be useful (until an integrated
> environment is here) if standard MAKE files are to be used, this should be
> controllable with a switch like "-disable-auto-source-search" that
> effectively disable the tests for multiple public classes/interfaces and
> source file name comparisions.
Unfortunately the compiler must do it the way it does it today. Some classes
are mutually depended and there is not "correct" order in which to compile
them. That's why the compiler has to be clever and do some of the work.
Have fun,
Arthur van Hoff
- ------------------------------
From: Laura Park <parkl@huachuca-simcenter.army.mil>
Date: Mon, 25 Sep 1995 08:01:36 -0700
Subject: Re: mo betta questions
YES,YES- we need some good old-fashioned documentation. Some of us can't always use our computer and some decent docs would help!
Laura Park
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 09:53:23 -0800 (PDT)
Subject: Re: Function keys
Hi George,
> I have written a sample program to print keyDown events.
>
> Testing it I get events for the most common keyboard
> keys (alpha, numbers, arrows etc), but see no input
> for the function keys.
>
> Is this the intended action, or am I doing something wrong?
>
> If it is the intended action, is there any way I can extend
> the keyboard handler to let me process the function keys?
We didn't add function keys yet because it is hard to come up
with a set of function keys that are on every keyboard! Maybe later.
Have fun,
Arthur van Hoff
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 09:52:11 -0800 (PDT)
Subject: Re: GridLayout weirdness...
Hi Pat,
> Am I missing something or does the following code behave in unexpected ways?
>
> I am trying to create a grid of four components, one of which
> is a panel, also with four components.
>
> When the panel layout is set to GridLayout its first two buttons never
> appear. When it is set to FlowLayout all is well unless I resize the
> appletviewer window, in which case the panel gets very confused.
>
> I have also tried adding the empty panel first and then it's components,
> which the same results. (I wouldn't have expected this to make a difference)
> Any ideas?
Have you tried refreshing the window? If the buttons appear after that it is
probably the repaint bug. We'll fix that in the next release.
Have fun,
Arthur van Hoff
- ------------------------------
From: S.P.Treacy@scotborders.co.uk (Scott Treacy)
Date: Tue, 26 Sep 1995 10:17:59 +0000
Subject: Re: Consoles and repaints
>
>
>Hi Elliotte,
>
>> Two questions that aren't apparently related:
>>
>> 1. In HotJava alpha 2 for NTand apparently on Solaris
>> there was always a console window open to receive the results of
>> commands like System.out.println and error messages. That apears to
>> have gone away in HotJava alpha 3 for NT. Is there a way to get it
>> back?
>
>I don't think so. The output goes to a log file on the PC.
Which is why I'm still using NTalpha2 instead of alpha3. Please put this
feature back!!!
>> 2. Is there a method I can call to force an applet to repaint?
>
>Yes. It is called repaint!
>
>Have fun,
>
> Arthur van Hoff
Scott
Scott Treacy - Java Development Team, TweedNet, Calligrafix.
aka Work - Tel: +44 (0) 1835 822990 Fax: +44 (0) 1573 430206
Elgeebar Smail: 1 Tweed Horizons Centre, St. Boswells, Scotland. TD6 0SG.
UNet#question Home - Tel: +44 (0) 1896 870490 Fax: +44 (0) 1896 757965
Smail: 17 Park Villa, Walkerburn, Borders, Scotland. EH43 4AN.
- ------------------------------
From: cmcmanis@scndprsn.Eng.Sun.COM (Chuck McManis)
Date: Mon, 25 Sep 1995 10:26:28 -0700
Subject: Re: Dynamic Loading of Classes
>In article Gregory Alan Bolcer <gbolcer@liege.ICS.UCI.EDU> writes:
>> I've programmed myself into a corner, and I am seeking advice
>>on the following problem. I have a Java unix process that is
>>maintaining a dynamically changeable object model (categories)
>>built on top of Java. The methods to these categories can be
>>dynamically changed at runtime and are implemented as Java classes
>>within a file directory.
Mike Responds...
>Sounds cool however, Java is not a dynamic language in the sense that
>Smalltalk is a dynamic language. This works it self back to the request for
>perform: capabilities ala Smalltalk. The reason for no perform: (as it was
>explained to me) is that it opens a big security hole. For example, a Nasty
>Old Java App (NOJA) could evoke the method "MySystem.sendUglyMailToMyBoss" if
>a class with such an interface exists. I guess that the NOJA could scan the
>class which it finds on a given workstation and try things at random causing
>all sorts of havoc.
Mike is correct, however if your already running UNIX processes then
you are not an applet and just a Java ap. Consider writing your own
"perform" class, to do some (most?) of it is fairly trivial.
NOTES: THE FOLLOWING CODE IS WRITTEN "on the fly" And probably won't
even compile, much less work, however it should provide sufficient
information to do what you want.
Write a class "DynamicMethodInvoker" which is defined something like:
class DynamicMethodInvoker {
static {System.loadLibrary("dynamix");}
private native Object executeDynamicMethod(Object o, String meth,
String sig, Object args[]);
public Object doDynamicMethod(Object o, String meth, String sig,
Object args[]) {
/* Implement some security policy here. Maybe call SecurityManger
canInvoke or something you make up, what ever you do, don't
let applets call this. */
SecurityManager.mySecurityPolicy();
return (executeDynamicMethod(o,meth, sig, args));
}
}
And in the C code write:
int parseSignature(char *sig) {
static char *cursig;
if (sig != NULL) {
cursig = sig; /* set the signature */
cursig = strchar(sig, '['); /* find the arguments */
return 0;
}
return (getnextparameter(cursig)); /* return next argument type
(int, object ref, etc) */
}
int sigComponents(char *sig) {
/* return number of arguments to the method */
}
ClassDynamicMethodInvoker_executeDynamicMethod(HObject *this,
HObject *that, HString *meth, HString *sig, HArrayOfObject *args) {
long res;
switch (sigComponents(sig)) {
case 0:
res = java_execute_dynamic_method(getEE(), unhand (that),
unhand(meth), unhand(sig));
break;
case 1:
parseSignature(sig);
res = java_execute_dynamic_method(getEE(), unhand (that),
unhand(meth), unhand(sig),getnextParameter(sig));
break;
...
/* repeat for as many arguments as you would like. */
}
type = parsesignatureResult(sig);
/* this should simply parse the return type. */
/* if it is a simple type (int, long, etc) then call
execute_java_constructor() on the result with the
simple type's class
(ie execute_java_constructor(..,"Integer", res,...)
*/
return res;
}
Note that amateur spelunkers should not try to do this, it will just
confuse you.
- - --Chuck
- ------------------------------
From: Guido.Campani@Italy.Sun.COM (Guido Campani - SUN Italy)
Date: Tue, 26 Sep 1995 11:25:26 +0100
Subject: ?Java interface to Oracle or other DB
A customer asked me the following and I wasn't able to answer:
Is there any class of objects to interface oracle or any other db ?
Thankyou for your help. Ciao, Guido.
PS
I'm not in the mailing list, please reply directly.
- ------------------------------
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Date: Mon, 25 Sep 1995 09:46:41 -0800 (PDT)
Subject: Re: AWT instance variables
Hi Ed,
> Here is a list of things that I, as a class designer, might want a subclass
> of an AWT object to do, which cannot be done within the current framework
> unless the new objects are part of the AWT package.
>
> 1) As a descendant of Component, set my parent directly. In fact, even the
> "add" method of the Container object would not work if it were not in the
> same package as Component.
>
> 2) As a descendant of Menu, change the order of my Menu items, or choose to
> add a new item anyplace but the end of the menu.
>
> 3) As a descendant of Container, sort my children in place.
Any of these operations would break the AWT if you would do them by
directly accessing the instance variables. I'm glad we stopped you!
> 4) As a descendant of FlowLayout, change my alignment.
The fact that the layout objects have private variables is broken.
I'll fix that.
> I'm sure I could come up with more. Note that these are all things an
> object would want to do to itself, not things it would allow other objects
> to do. The way AWT is written, subclasses as a rule do not have any more
> privileged access to their ancestors' instance variables (which could
> really be thought of as their own instance variables) than any other class,
> thus making AWT extremely difficult to extend.
I disagree. It makes the AWT safer.
> I'd like to know if this state of affairs is going to continue in future
> releases.
Absolutely!
Have fun,
Arthur van Hoff
- ------------------------------
From: mikec@metronet.com (Mike Christiansen)
Date: Tue, 26 Sep 1995 05:09:12 LOCAL
Subject: Re: [Q]: How to draw a point (new api)?
In article Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM> writes:
>> I was just wondering if there is a method to draw/color a single point
>> in the new api??
>>
>> Something similar to XDrawPoint in X11.
>I guess you can use:
> g.drawLine(x, y, x, y);
>
>or
> g.fillRect(x, y, 1, 1);
Not very efficient, and hardly a solution. I hope that the graphic
context is expanded in the future to include such useful primitives.
Thanks,
Mike.
- - -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Mike Christiansen
mikec@metronet.com
- ------------------------------
From: meessen@cppm.in2p3.fr (Christophe Meessen)
Date: Tue, 26 Sep 1995 14:13:03 +0100
Subject: Q: java profiling on WiNT with alpha3
I failed to do profiling on an a small program I wrote.
When lounching the java -prof myProgram the program terminates correctly
but a fatal error is produced just afterward. It looks like a try to access
address 0x000000.
The java.prof file is created but looks empty.
Running javaprof produces an exception from thread main. Here is the message:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException
at
java.tools.javaprof.Prof.main(F:\ws\liveoak.porting\src\share\java\lang\java
\tools\javaprof\Prof.ja
Did anybody tried this tool before on WinNT alpha3 ? What did I do wrong ?
Bien cordialement,
Ch.Meessen
- ------------------------------
From: Sami.Shaio@Eng.Sun.COM (Sami Shaio)
Date: Sun, 24 Sep 1995 22:28:25 -0700
Subject: Re: awt question
Because the layout manager is changing the label's location to be
horizontally centered.
- - --sami
- ------------------------------
From: chi.nguyen@gs.com (Chi Nguyen)
Date: Tue, 26 Sep 95 10:11:09 EDT
Subject: Win95 JDK available?
The Java home page shows that a Win95 HotJava browser is available, but is
there a JDK for Win95 yet? If so, where can I get it? Thanks.
Chi
- ------------------------------
From: James L Weaver/DELCO <JLWEAVER@mail.delcoelect.com>
Date: Tue, 26 Sep 1995 08:38:54 -0500 (EST)
Subject: GUI design
Is there a way to position GUI widgets on a dialog by using coordinates and
sizes (as opposed to using layouts)? It would be nice to use a conventional
dialog design tool, make note of the coordinates and sizes for each widget, and
code them in Java.
Thanks,
Jim Weaver
- ------------------------------
From: "Steve V. Yalovitser" <root@cyberpunk.com>
Date: Tue, 26 Sep 1995 10:25:47 +0900 (EDT)
Subject: putmsg multiply defined in java VM (JDK) (fwd)
Hiya,
Ive recently run into a lot of core dumps from failed asserts around
iomgr.c(line 628) the call stack's last call is putmsg before panic. The
problem is
that putmsg is in libc.a as well. The cores result because I think the
_wrong_putmsg is being called. In particular one core has a stack which has:
panic()
putmsg()
t_sndudata()
clnt_dg_call()
_nis_finddirectory_r()
The putmsg above is probably called out from t_sndudata (a system call). The
above is repeatable on a few different architectures running solaris 2.4. It
isrepeatable easily by doing any calls that require hostname lookup (for
instance through InetAddress.java). Thanks in advance for any help.
- ------------------------------
From: arnold@cocolat.East.Sun.COM (Ken Arnold - Sun Labs)
Date: Tue, 26 Sep 1995 10:27:32 -0400
Subject: Re: interfaces are NO substitution for method pointers
I suppose I'm not as wise as Arthur -- I'm going to take *one* crack
at trying to convince.
Using methods, if you want, say, a callback from a button click, you
say something like this (in the officially approved signature):
void CancelButtonCallbackFunc(Button *button, void *my_data)
{
do_cancel((Operation *) my_data); // whatever
}
Using an interface, it would look like this:
class CancelButtonCallback extends Button {
Operation *my_data;
void pressed()
{
do_cancel(); // whatever
}
}
Over this you make a noise? In the first case, you have to
invent a name for the new function
create the button with a void * for your own data
receive a button * to tell you which button
receive a void * you cast back to your own data
do your thing
In the second case you have to
invent a name for the new button type
create a button of that new type
have any data you want as data member (type safe, notice no casting)
do your thing
At the very worst, you can argue that the new system maybe has a very
few more keystrokes. You have to admit that it adds some type safety,
and arguably OO cleanliness and reusability. This doesn't sound like a
problem to me. In fact, it smells a lot like a *solution* to some
problems.
Ken Arnold
- ------------------------------
From: Andrew Wason <aw@bae.bellcore.com>
Date: Tue, 26 Sep 95 10:35:27 -0400
Subject: Re: host handles & the like
Mike Klein <mklein@ossi.com> writes:
> This is my nth time posting this question so I don't have any grandious
> dreams of it being answered, but here goes anyways...
>
> #1 - I need access to host window handles! The NT source release doesn't
> come with key source files for the runtime, making host handle extraction
> from a WINDOW object impossible. The raw HWND/HANDLE is needed because the
> release of AWT I am using doesn't support Z-Ordering of window planes, and
> RE-Parenting of windows, two things pretty key for drag&drop and windowing
> in general.
Let me know if you get an answer to this one.
Are you creating your own native HWNDs too? I've had trouble
with that since an HWND is owned by the native thread it was
created in, and applets are initialized in a transient thread (so
the HWNDs are destroyed as soon as the thread returns). How does
the AWT manage to get all it's HWNDs owned by the "AWT WServer
Thread"?
> #2 - I need access to a .LIB file or .DLL from NT so I can finish my perform
> method. I need these files so I can statically/dynamically bind to
> java_execute_constructor and java_execute_method.
The DLLs are in \hotjava\bin. javai.dll contains
execute_java_constructor and execute_java_dynamic_method. You
can use VC++ to create an import .LIB from the DLL by creating a
.DEF file and using LIB /DEF. See
http://www.microsoft.com/Support/KBSL/DEVELOPR/visual_c/Q131313.htm
for instructions.
Andrew
_______________________________________________________________________________
Andrew Wason Bell Communications Research
aw@bae.bellcore.com Piscataway, NJ
- ------------------------------
From: enrique@foozy.sun.com (Enrique D Espinosa)
Date: Tue, 26 Sep 1995 08:39:31 +0600
Subject: Placing applet in HTML page
Hi:
I have an applet that looks somewhat like this:
//
// The main structure of the program.
//
public class SoundTest extends java.applet.Applet {
// global variable section. this is where our vars will be stored
// and declared.
// ---------------------------------------
Font titleFont; // so we are able to display cool things
Font copyrightFont; // little font to place my name...
Font textFont; // for the overall text format
AudioClip roosterAudio; // for the introductory theme...
AudioClip spaceAudio; // and other junkies...
AudioClip helloAudio;
AudioClip beepAudio;
CardPanel cards; // where the buttons reside...
..
..
..
..
Runs fine, bue when I try to place it in an html document:
<html>
<head>
<title>Demostracion #5a de Applets en Java</title>
<body>
<hr size=8>
<br>
Este applet es un demostrador de sonidos que nos sirve para
observar las caracteristicas de las classes para implementar
botones.
Este es el applet Demo5a:
<br>
<!--
<!-- changes made in order to comply with JDK prebeta 1
<!-- september 20, 1995.
<!-- used to be:
<!-- app class="Demo5"
<!-- now is:
<applet code="SoundTest.class" width=400>
</applet>
<br>
<hr size=8>
</body>
</html>
It won't do a thing! I compiled the thing using the JDK.
Help!
- - -----------------------------------------------------
*************** *************** ***************
|*************** *************** ***************
| **** **** **** **** ****
| **** **** **** **** ****
| ********* **** **** **** ****
| ********* **** **** **** ****
| **** **** **** **** ****
* **** **** **** **** ****
* **** **** **** **** ****
* **** **** **** **** ****
* **** *************** ***************
* **** *************** ***************
* .----------------------------------------------------.
* | MC Enrique David Espinosa | http:// |
* | Depto de Computacion | www.ccm.itesm.mx/ |
* | ITESM-CCM | ~enrique/ |
* | voice: (525)673-1000x4231 | EECDOCS/ |
*| fax: (525)673-2500 | Main.html |
`----------------------------------------------------'
- ------------------------------
From: Tako Schotanus <Tako.Schotanus@bouw.tno.nl>
Date: Tue, 26 Sep 1995 15:44:52 +-100
Subject: RE: Function keys
>> If it is the intended action, is there any way I can extend
>> the keyboard handler to let me process the function keys?
>
>We didn't add function keys yet because it is hard to come up
>with a set of function keys that are on every keyboard! Maybe later.
Hmmm, and what if you define the most common ones like f1 - f10 and
cursor keys? If any of these doesn't exist for the platform you're using
you could always map some other key(s) to act like function keys.
Or you could have default key-bindings which will always be available,
whether your platform/keyboard has function keys or not (eg F1 - F10
might map to CTRL 1 - 0 and the cursor keys to CTRL u, d, l & r).
- - - Tako
- ------------------------------
From: Andrew Wason <aw@bae.bellcore.com>
Date: Tue, 26 Sep 95 11:16:29 -0400
Subject: Re: mo betta questions
garya@village.org (Gary Aitken) writes:
>
> >YES,YES- we need some good old-fashioned documentation. Some of us can't
> always use our computer and some decent docs would help!
>
> As a first cut, How about making the Print option work in the HotJava
> browser? That way at least we could generate something to use off line.
You can use the Mozilla Print Gidget from within HotJava:
http://home.mcom.com/people/mtoy/cgi/www-print.cgi
It appears to be broken right now though, hopefully this is temporary.
Andrew
_______________________________________________________________________________
Andrew Wason Bell Communications Research
aw@bae.bellcore.com Piscataway, NJ
- ------------------------------
From: jpayne@starwave.com (Jonathan Payne)
Date: Tue, 26 Sep 1995 08:22:04 -0700
Subject: Re: Placing applet in HTML page
There's no application written yet that can view your applet, except
for the applet viewer.
Netscape 2.0 should be able to run it when it comes out. Also the
next version of HotJava.
But for now just the applet viewer.
PS: I just made this up. But I think I am right.
- ------------------------------
From: fsuarez@ll.iac.es (Francisco Valenzuela Suarez)
Date: Tue, 26 Sep 1995 15:45:33 GMT
Subject: calling native C/C++ : portability
Hello javanities.
I know JAVA uses extern "C" to include C code. But I wonder if that restricts the resulting program portability.
How does Java implement extern "C"? Are the C code translated to bytecodes?
Thanks.
Gracias.
Fran Valenzuela.
- ------------------------------
From: mtw@kodak.com (Mary White)
Date: Tue, 26 Sep 1995 11:50:38 -0400
Subject: hideing/showing awt components
Hello,
In my current implementation I have a number of different
interfaces I need to present to the user. My strategy was
to create one Applet with n number of awt components and
just show and hide depending on where I am in the implementation
of the program.
So in my action method I determine which button was selected
perform the appropriate action and then try to hide the
displayed components and show the next interface. However
it will not hide the displayed components.
If I eliminate the call to display the new interface and just
hide the displayed components then it works fine. But once I add
the call to display the new interface, the old components no longer
hide and the new ones are never displayed.
Do I need to sleep or something. Not sure what is going on?
Any help would be greatly appreciated!!
Thanks
Mary White
- ------------------------------
End of java-interest-digest V1 #188
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------------------------------
From: anchor@open.rd.nttdata.jp (Tatsuya Nakamura)
Date: Thu, 28 Sep 95 18:15:18 JST
Subject: Q: communicate with applets(applet <---> applet)
Hello Javafans
Is there a method that support communication with applets(send method to
the other applet's objects or share the class vars)?
Thanks appreciate for your help
- ---
Tatsuya Nakamura : anchor@open.rd.nttdata.jp
tel: +81 3 5546 9566, fax: +81 3 5546 9567
------------------------------
From: Pat Niemeyer <pat@icon-stl.net>
Date: Thu, 28 Sep 1995 04:32:07 -0500 (CDT)
Subject: Re: hideing/showing awt components
On Tue, 26 Sep 1995, Mary White wrote:
> In my current implementation I have a number of different
> interfaces I need to present to the user. My strategy was
> to create one Applet with n number of awt components and
> just show and hide depending on where I am in the implementation
> of the program.
Have you looked at java.awt.CardLayout ?
It might be useful for this.
Pat
------------------------------
From: Pat Niemeyer <pat@icon-stl.net>
Date: Thu, 28 Sep 1995 04:53:48 -0500 (CDT)
Subject: Re: Spare CPU cycles
On Wed, 27 Sep 1995, Elliotte Rusty Harold wrote:
> There have been a number of problems solved by harnessing the power
> of multiple computers working in parallel such as the recent cracking
> of Netscape's 40-bit security code and my own work on optimal batting
> orders (not the most significant projects I admit). However until now
> the lead programmer had to be trusted on all the systems he or she
> used. That is no longer true if the code is written in java.
>
> Any thoughts?
People can build whatever tools they like to manage the applets they
pull in from the net. This will not be a serious problem.
Think of how cool it would have been for the RSA-129 factoring project
to have been undertaken in Java.
People without any special software, administration, or knowledge could
have participated by simply parking their browser on a web page.
Oops, have to do some work? Just surf on... When you're done come back
and the applet starts() and picks up where you left off.
God I love this language.
Java is going to eat the world alive.
Pat
------------------------------
From: sweh@mpn.com (Stephen Harris)
Date: Thu, 28 Sep 1995 12:02:48 +0100 (BST)
Subject: Re: [Q] - "javac: invalid atgument: noclobber"
>
> $ javac HelloWorld.java
> javac: invalid argument: noclobber
>
> i'm sure i put HelloWorld.java file into "classes" directory.
> what am i missing here?
This is a problem Sun haven't learnt about yet, and is around in LOTS
of Sun programs :-( It just hit me in the CDE install script :-(
You are using ksh as your shell, and you have $ENV pointing to a file
that has 'set -o noclobber' (or similar setup). Now the javac script begins
#!/usr/bin/ksh
which will run your $ENV file, and when it tries to overwrite a file it will
fail miserably.
Solutions:
1) Put a -p flag on the first line of the script
I write ALL my scripts this way. It tells ksh to use /etc/suid_profile
instead of $ENV - suid_profile (if it exists!) is generally a lot lot
cleaner and won't have these problems.
2) remove the offending line from the $ENV file
3) Modify the wrapper and add 'set -o clobber'
4) Write a wrapper to unset ENV and call the java script wrapper
- --
rgds,
Stephen
------------------------------
From: dufourd@enst.enst.fr
Date: Thu, 28 Sep 95 12:17:02 +0100
Subject: Thoughts on the multiplication of files
I have asked already for a solution to the "many small class files" problem.
Now I think there are two possible approaches.
(1) Treat it as a Java specific problem :
Roughly, that would mean extend the applet tag to allow for the specification
of "code=" as a Jarchive, which would be processed as a current directory.
(2) The problem is wider : any HTML page with lots of subelements (e.g. GIF)
would benefit from bundled loading. So why not create a new content type,
e.g. application/packed, which would be something like a tar file of
everything useful for the page. The applet tag would first look into it
for class files before going along the path.
Questions: Is this reasonable ? Is it new or is there already some people
working along those lines ? Is it the place to discuss this ?
Maybe (2) would be better, but because of inertia, we should do (1) now ?
JCD
- ------------------------------------------Java, Lisp & Theater----------------
Jean-Claude Dufourd Departement Electronique,ENST Tel: +33 1 45 81 78 07
46 rue Barrault, 75013 Paris Fax: +33 1 45 80 40 36
Email: dufourd@elec.enst.fr URL: http://www-elec.enst.fr/~dufourd/jcd.html
------------------------------
From: rcampbell@fdic.gov
Date: Thu, 28 Sep 95 9:36:40 -0400
Subject: Ideal Java machine?
I've been getting the Java digest, and after reading a lot of industry
comments (Gartner Flash of 9/22, Forrester Brief of 9/21), and reading Scott
McNealy's comments that companies are already building a "java terminal", I
wondered just what would be an ideal "Java Terminal" if that is the correct
phrase. Apple is designing the Pippin; Nintendo has the Ultra 64; both are
under $500 as McNealy (and Larry Ellison too in the Financial Times)
specified.
If Java embedded in Netscape, for example,is a true network operating system,
and presuming the functionality, is it safe to conjecture that I can junk
most of my Intel/microsoft pc's and their attendant support costs by
substituting the Java Terminal?
------------------------------
From: Mentor <mentor@io.org>
Date: Thu, 28 Sep 1995 10:56:14 -0400 (EDT)
Subject: Re: Socket Communication
On Wed, 27 Sep 1995, Joseph Jones wrote:
> The API for the sockets shows all communications using byte arrays. I need
> tp transmit and receive strings. Is there a way to convert a string object
> to a byte array??
>
> joe
As for transmitting and receiving strings, just create a TextInputStream or a
PrintStream from what the socket gives you, and you're all set for whichever
direction you wanted to go in.
Cheers,
David Forster
Mentor Software Solutions
<a href="http://www.io.org/~mentor">Mentor Software Solutions</a>
------------------------------
From: etmmhann@kryten.cms.livjm.ac.uk
Date: Thu, 28 Sep 1995 15:59:02 +0100 (BST)
Subject: How do I do a getenv under the pre-beta JDK?
Hi,
Since the System.getenv("....") command has been
made obselete in the pre-beta JDK, how can you
extract the value of environment variables under
the JDK frozen api?
- --
Martin Hanneghan
Liverpool John Moores University
------------------------------
End of java-interest-digest V1 #195
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