Re: [Fwd: Java Applet IIOP Call-In with Release 3C--How dowe speed up d

Question

Hi Michael,
We have done exactly what you describe and have avoided the slow applet
download times. Although it can be a bit tricky, it is possible to use
the ORB bundled inside the Netscape 4.0 browser (Visibroker for Java by
Visigenic). Most of the code should follow Netscape's examples (on
http://developer.netscape.com)--just remember to initialize the ORB by
passing a reference to the current applet in orb_init() (so that you
invoke something like orb_init(this) [assuming you are extending
java.applet.Applet]). Pulling up the Java console within your web
browser should help debug quite a bit (a lot of debug messages will get
printed there the ORB is having problems).
Netscape has just implemented the applet caching schemes you describe,
so it probably shouldn't matter too much if you use another vendor's
ORB (we've done this with Iona's OrbixWeb). If you use ZIP files, they
have to be uncompressed, and I don't think that the browser will cache
them between browser sessions. Netscape 4.0 does seem to handle
compressed JAR files just fine and it does indeed cache them between
browser sessions. I'd go with the JAR format anyway since the ZIP
bundling was just a workaround until Sun got their act together in the
1.1 JDK.
By the way, you also might want to take advantage of the code-signing
and capabilities APIs of Netscape if you are going to invoke methods on
objects not resident on your web server. Otherwise, you will probably
run into the (in)famous browser applet security restrictions and you may
have other problems doing things like callbacks from Forte, etc.
If you want more detail on how it works, let me know and I can post some
examples.
Oh, one last thing: we are a consulting firm specializing in these kinds
of things :)
Bill
Subject: Java Applet IIOP Call-In with Release 3C--How do we speed up download time.
Date: Wed, 2 Jul 1997 09:10:31 -0500
From: Michael Nelson <[email protected]>
To: "'[email protected]'" <[email protected]>
We have successfully implemented a simple Java Applet that calls into
Forte Services via IIOP. However, the duration of the download time
for
Applet and its required class files is UNACCEPTABLE in a typical
INTERNET environment where 28.8K modems and multiple hops around the
net
are not uncommon. We dialed into our network at 28.8K (but no
hopping),
and found that download times varied from 1.5 - 2.0 minutes. This is
unacceptable, even by internet standards. We have been using the
Visigenic Visibroker product as the ORB.
After doing some investigation, we've come up with several ideas to
speed up download time:
1. Figure out how to use the Visigenic components (CORBA/IIOP class
files) that come bundled with the latest version of the Netscape
Navigator browser, so that they don't have to be downloaded
2. Figure out how to use ZIP files. Here's what I've read: "Since
the
introduction of Netscape Navigator 3.0, you can specify an
uncompressed
.zip file as an addition to the code base of your application. By
specifying a ZIP file, the browser will load your applet's classes
from
a specified ZIP file before it searches the code base. This ZIP can
improve applet download time by reducing the number of HTTP
connections
required to fetch applet code. As an added benefit, Netscape caches
the
single ZIP file so that it will not reload your applet unless the date
of the ZIP file has changed."
3. Figure out how to use JAR files. Here's what I've read: "JAR
stands for Java archive. It's a file format based on the popular ZIP
file format and is used for aggregating many files into one. Although
JAR can be used as a general archiving tool, the primary motivation
for
its development was so that Java applets and their requisite
components
can be downloaded to a browser in a single HTTP transaction, rather
than
opening a new connection for each piece. This greatly improves the
speed with which an applet can be loaded onto a web page and begin
functioning. The JAR format also supports compression, which reduces
the
size of the file and improves download time still further."
Unfortunately, we've been unable to get any of these approaches to
work.
Has any one used these or other approaches to speed up applet
download
time? Or, does anyone know of consulting firms that specialize in
this
sort of thing?
Thanks in advance for your help.
Mike Nelson, Project Leader
Metrix, Inc.
[email protected]
414-798-8560 x1157
Billy L. Williams, Jr. | email: [email protected]
Sage Solutions, Inc. | Tel: [phone] (x506) Fax: [phone]
| Pager: [phone] (page me if urgent)

Answer 1

Hi Michael,
We have done exactly what you describe and have avoided the slow applet
download times. Although it can be a bit tricky, it is possible to use
the ORB bundled inside the Netscape 4.0 browser (Visibroker for Java by
Visigenic). Most of the code should follow Netscape's examples (on
http://developer.netscape.com)--just remember to initialize the ORB by
passing a reference to the current applet in orb_init() (so that you
invoke something like orb_init(this) [assuming you are extending
java.applet.Applet]). Pulling up the Java console within your web
browser should help debug quite a bit (a lot of debug messages will get
printed there the ORB is having problems).
Netscape has just implemented the applet caching schemes you describe,
so it probably shouldn't matter too much if you use another vendor's
ORB (we've done this with Iona's OrbixWeb). If you use ZIP files, they
have to be uncompressed, and I don't think that the browser will cache
them between browser sessions. Netscape 4.0 does seem to handle
compressed JAR files just fine and it does indeed cache them between
browser sessions. I'd go with the JAR format anyway since the ZIP
bundling was just a workaround until Sun got their act together in the
1.1 JDK.
By the way, you also might want to take advantage of the code-signing
and capabilities APIs of Netscape if you are going to invoke methods on
objects not resident on your web server. Otherwise, you will probably
run into the (in)famous browser applet security restrictions and you may
have other problems doing things like callbacks from Forte, etc.
If you want more detail on how it works, let me know and I can post some
examples.
Oh, one last thing: we are a consulting firm specializing in these kinds
of things :)
Bill
Subject: Java Applet IIOP Call-In with Release 3C--How do we speed up download time.
Date: Wed, 2 Jul 1997 09:10:31 -0500
From: Michael Nelson <[email protected]>
To: "'[email protected]'" <[email protected]>
We have successfully implemented a simple Java Applet that calls into
Forte Services via IIOP. However, the duration of the download time
for
Applet and its required class files is UNACCEPTABLE in a typical
INTERNET environment where 28.8K modems and multiple hops around the
net
are not uncommon. We dialed into our network at 28.8K (but no
hopping),
and found that download times varied from 1.5 - 2.0 minutes. This is
unacceptable, even by internet standards. We have been using the
Visigenic Visibroker product as the ORB.
After doing some investigation, we've come up with several ideas to
speed up download time:
1. Figure out how to use the Visigenic components (CORBA/IIOP class
files) that come bundled with the latest version of the Netscape
Navigator browser, so that they don't have to be downloaded
2. Figure out how to use ZIP files. Here's what I've read: "Since
the
introduction of Netscape Navigator 3.0, you can specify an
uncompressed
.zip file as an addition to the code base of your application. By
specifying a ZIP file, the browser will load your applet's classes
from
a specified ZIP file before it searches the code base. This ZIP can
improve applet download time by reducing the number of HTTP
connections
required to fetch applet code. As an added benefit, Netscape caches
the
single ZIP file so that it will not reload your applet unless the date
of the ZIP file has changed."
3. Figure out how to use JAR files. Here's what I've read: "JAR
stands for Java archive. It's a file format based on the popular ZIP
file format and is used for aggregating many files into one. Although
JAR can be used as a general archiving tool, the primary motivation
for
its development was so that Java applets and their requisite
components
can be downloaded to a browser in a single HTTP transaction, rather
than
opening a new connection for each piece. This greatly improves the
speed with which an applet can be loaded onto a web page and begin
functioning. The JAR format also supports compression, which reduces
the
size of the file and improves download time still further."
Unfortunately, we've been unable to get any of these approaches to
work.
Has any one used these or other approaches to speed up applet
download
time? Or, does anyone know of consulting firms that specialize in
this
sort of thing?
Thanks in advance for your help.
Mike Nelson, Project Leader
Metrix, Inc.
[email protected]
414-798-8560 x1157
Billy L. Williams, Jr. | email: [email protected]
Sage Solutions, Inc. | Tel: [phone] (x506) Fax: [phone]
| Pager: [phone] (page me if urgent)