JET 3270 Documentation > Configuration
Configuration
In this section:
The portion of JET 3270 which runs inside the user's
web browser is known as a JavaTM applet. The applet is a set
of class files. Class files are the compiled Java
code. These class files are provided with the JET 3270
distribution as JAR files
(JET3270E.jar and JET3270SU.jar) and
as a distribution unit cabinet archive file (JET3270.cab).
The JAR
files are used by Java Plug-in, the Netscape Java virtual
machine (JVM) and Mac OS X and the distribution unit is used
by the Microsoft virtual machine (VM).
To include a JET 3270 applet in a web page, the web
page needs to include an <APPLET> tag that
specifies
CODE=com.platypuspartners.jet3270.JETApplet3270.class.
You also need applet parameters or JavaScript code to make
the browser install and/or use the appropriate distribution
unit or JAR file. What is required depends on the intended
Java virtual machine (JVM). See the JVM specific
sections below for this information.
The applet also needs a space on the screen into
which it can draw. This is specified by the WIDTH
and HEIGHT attributes of the <APPLET> tag.
There are several web page editors that will
allow you to insert a reference to an applet
without the web page designer being aware of the
HTML commands that the editor generates. It is
equally valid for the web page designer to use
such an editor so long as the CODE, ARCHIVE,
WIDTH and HEIGHT attributes and the
"useslibrary" and "namespace" parameters are set
correctly. Note also that class file names are
case sensitive.
Although there are many other class files for the
JET 3270 applet stored in the
JET3270.cab and
JET3270E.jar files,
the web page designer need not specify these in
the <APPLET> tag. The web browser will
automatically identify the other class files that
the JET 3270 applet needs.
Applets can be "configured" by including
parameters embedded in the <APPLET>
tag. The web page designer can include parameters
using <PARAM> tags. Refer to Applet Parameters for
more information.
For Sun JVM environments you need a "cache_archive" applet
parameter, assuming you wish to take adavantage of applet
caching.
Java Plug-in 1.4's applet caching feature
minimizes the number of times the JET 3270 class files
are downloaded from the web server.
The applet parameter is specified by a PARAM tag with
NAME and VALUE attributes inside the APPLET tag. For example:
<PARAM NAME="cache_archive" VALUE="JET3270E.jar">
The value of "cache_archive"
must be "JET3270E.jar", the name of the JAR file.
A simple web page example follows:
<HTML>
<HEAD>
<TITLE>JET 3270 example -
Sun JVM using applet caching</TITLE>
</HEAD>
<BODY>
<APPLET
CODE=com.platypuspartners.jet3270.JETApplet3270.class
WIDTH=600 HEIGHT=450>
<PARAM NAME="cache_archive"
VALUE="JET3270E.jar">
Your Web Browser is not currently
Java-enabled.
</APPLET>
</BODY>
</HTML>
When the web browser receives the <APPLET>
tag, it automatically requests that the web
server transfer the JAR file
(JET3270E.jar) if it is not cached
and begins executing JET 3270.
More information about applet caching can be found in the
"Applet
Caching" section of the
Java
Plug-in Developer Guide.
For Mac OS X and when you do not want applet caching for
Sun JVM environments you must specify
ARCHIVE=JET3270E.jar as an attribute of the
APPLET tag.
A simple web page example follows:
<HTML>
<HEAD>
<TITLE>JET 3270 example -
Mac OS X and Sun JVM with no applet caching</TITLE>
</HEAD>
<BODY>
<APPLET
CODE=com.platypuspartners.jet3270.JETApplet3270.class
ARCHIVE=JET3270E.jar
WIDTH=600 HEIGHT=450>
Your Web Browser is not currently
Java-enabled.
</APPLET>
</BODY>
</HTML>
When the web browser receives the <APPLET>
tag, it automatically requests that the web
server transfer the JAR file
(JET3270E.jar)
and begins executing JET 3270.
For the Microsoft virtual machine
(VM) you need "useslibrary", "namespace",
"useslibrarycodebase" and "useslibraryversion" applet
parameters. They are specified by PARAM tags with NAME and
VALUE attributes inside the APPLET tag. For example:
<PARAM NAME="useslibrarycodebase" VALUE="JET3270.cab">
The value of "useslibrary" must be "JET 3270", "namespace"
must be "com platypuspartners jet3270" and
"useslibrarycodebase" must be
"JET3270.cab", the name of the
distribution unit. The value for "useslibraryversion" must
match the distribution unit version found in the Release Notes
of the version of JET 3270 you are using. It is four numbers
separated by commas, for example 2,6,2,32767, and is different
for each release of JET 3270. When you upgrade to a later
version of JET 3270 you must change the
"useslibraryversion" applet parameters in your web pages.
A simple web page
example follows:
<HTML>
<HEAD>
<TITLE>JET 3270 example - Microsoft VM</TITLE>
</HEAD>
<BODY>
<APPLET
CODE=com.platypuspartners.jet3270.JETApplet3270.class
WIDTH=600 HEIGHT=450>
<PARAM NAME="useslibrary"
VALUE="JET 3270">
<PARAM NAME="namespace"
VALUE="com platypuspartners jet3270">
<PARAM NAME="useslibrarycodebase"
VALUE="JET3270.cab">
<PARAM NAME="useslibraryversion"
VALUE="2,6,2,32767">
Your Web Browser is not currently
Java-enabled.
</APPLET>
</BODY>
</HTML>
Note that the text "Your Web
Browser is not currently Java-enabled"
will only appear in browsers that
are not Java-enabled, or which have their Java
support currently disabled. A user must have Internet Explorer
5.01 or later and VM build 3167 or later and must not have
disabled Java.
When Internet Explorer first receives the APPLET tag it
will request the distribution unit from the web server then
install the JET 3270 classes from it onto the local
file system. Subsequently Internet Explorer will check that
the version specified by "useslibrary" is the same as (or
older than) the version of the installed JET 3270 class
files. Only if the installed class files are an older
version will the distribution unit be requested from the
web server again.
More information about distribution units can be found in
the Microsoft SDK for Java 4.0 documentation.
For Communicator's built-in Java virtual machine (JVM)
you need JavaScript code to download and
install the JET 3270 classes from the
JET3270SU.jar
SmartUpdate JAR file. Part of the JavaScript needed is
provided in the updateJET3270.js file in the applet
directory of the JET 3270 distribution. A simple web page
to install the JET 3270 using this file follows:
<HTML>
<HEAD>
<TITLE>JET 3270 example - Communicator Installation</TITLE>
</HEAD>
<BODY>
<SCRIPT LANGUAGE="JavaScript" SRC="updateJET3270.js">
</SCRIPT>
<SCRIPT LANGUAGE="JavaScript">
trigger = netscape.softupdate.Trigger;
if ( trigger.UpdateEnabled() )
{
if (updateJETIfRequired("JET3270SU.jar"))
{
document.writeln("Downloading and installing a new version");
}
else
document.writeln("A current version is already installed");
}
else
{
document.writeln("SmartUpdate is disabled");
}
</SCRIPT>
The updateJETIfRequired function in updateJET3270.js
initiates the downloading and installation of the JET
3270 class files if the version specified in the
function is newer than the version of any currently installed
class files. The user must quit and restart Communicator
before the installed class files can be used.
When you upgrade to a newer release of JET
3270 you must replace the old updateJET3270.js
file with the one from the new release.
Once the JET 3270 class files are installed Communicator
will find them solely by the CODE attribute of the APPLET
tag. A simple web page to run JET 3270 for Communicator
follows:
<HTML>
<HEAD>
<TITLE>JET 3270 example -
Communicator</TITLE>
</HEAD>
<BODY>
<APPLET
CODE=com.platypuspartners.jet3270.JETApplet3270.class
WIDTH=600 HEIGHT=450>
Your Web Browser is not currently
Java-enabled.
</APPLET>
</BODY>
</HTML>
Your could combine the web pages used to install the class
files and to run JET 3270 by replacing the code that generates
the "Current version is already installed" message with code to
generate the APPLET tag. Note that users would still have to
quit and restart Communicator after installing the class files
before running JET 3270.
There is more information about SmartUpdate in Netscape's
SmartUpdate for Content Developers note and SmartUpdate Developer's Guide.
You can run JET 3270 in Communicator's built-in
Java virtual machine (JVM) without using
SmartUpdate to install the class files. In this case you
must specify ARCHIVE=JET3270E.jar as
an attribute of the
APPLET tag. A simple web page example follows:
<HTML>
<HEAD>
<TITLE>JET 3270 example -
Communicator</TITLE>
</HEAD>
<BODY>
<APPLET
CODE=com.platypuspartners.jet3270.JETApplet3270.class
ARCHIVE=JET3270E.jar
WIDTH=600 HEIGHT=450>
Your Web Browser is not currently
Java-enabled.
</APPLET>
</BODY>
</HTML>
Each time Communicator loads the APPLET
tag it will request the JET3270E.jar file from
the web server and download it, unless it has a copy cached.
You may need to configure your browser to use your desired
Java virtual machine (JVM). Platypus Partners recommends that
Windows users use the Sun JVM.
The Sun Java Runtime Environment (JRE) includes the Sun
Java Virtual Machine (JVM) and the Java Plug-in. It can be
downloaded from http://java.sun.com/getjava/download.html.
The Java Plug-in allows browsers to run JET 3270 in the
Sun JVM.
To configure Internet Explorer to use the Sun JVM:
A) During installation of the JRE you will see "Java(TM) Plug-in
will be the default Java runtime for the following browser(s)".
Ensure that Microsoft Internet Explorer is selected.
OR
B) After installing the JRE, follow these steps:
- Select Start -> Settings -> Control Panel
- Double click the Java Plug-in icon
- Select the Browsers tab
- Select Microsoft Internet Explorer
- Click Apply>
Note: You may need to be the administrator user to make this change.
You can see more detailed instructions on the
Setting the Default Java Runtime Environment
page on Sun's website.
You can install the JRE during Netscape 7 installation by choosing
the custom set up type and selecting the Sun Java 2 component. The
JRE is not inclued in the Typical set up. Netscape 7 will
automatically be configured to use the Sun JVM.
If you selected Sun Java 2 when installing Netscape 6 the version
of the JRE installed is not supported by JET 3270. You will
need to install JRE 1.4 or later.
To configure Netscape 6 or 7 to use the Sun JVM follow these
steps:
- Select Start -> Settings -> Control Panel
- Double click the Java Plug-in icon
- Select the Browsers tab
- Select Netscape 6
- Click Apply
Note: You may need to be the administrator user to make this change.
If the Sun JVM has not been installed then Internet Explorer
will use the Microsoft VM. Windows XP does not include the
Microsoft VM. If you do not have a supported version of the Microsoft VM
download and install the
Sun JVM.
If the Sun JVM has been installed but you wish to use the
Microsoft VM, follow these steps:
- Select Start -> Settings -> Control Panel
- Double click the Java Plug-in icon
- Select the Browsers tab
- Deselect Microsoft Internet Explorer
- Click Apply
Note: You may need to be the administrator user to make this change.
Netscape Communicator versions prior to 4.78 always use the
built-in Netscape Java virtual machine (JVM).
Communicator 4.78 to 4.8 include support for the Sun JVM.
To use the Netscape JVM follow these steps:
- Start Communicator
- Select Edit -> Preferences
- Select Advanced from the Category list
- Select Enable Java
- Deselect Enable Java Plugin
- Click OK
- Exit Communicator
Mac OS X includes support for Java in the operating system. To
enable Java in Internet Explorer follow these steps:
- Start Internet Explorer
- Select Explorer -> Preferences
- Select the Java sub-catetory of the Web Browser category
- Select Enable Java in the Java Options section
- Click OK
- Quit Internet Explorer
Applet parameters appear in the web page used to load JET
3270. They are used to configure JET 3270.
For example, applet parameters specify the names and URLs
of web sessions that JET 3270 users can open.
Applet parameters are specified with <PARAM> tags
enclosed by the
<APPLET> and </APPLET> tags.
An example of an <APPLET>
tag which loads
JET 3270 and specifies two web sessions, is:
<APPLET CODE=com.platypuspartners.jet3270.JETApplet3270.class
ARCHIVE=JET3270E.jar
WIDTH=300 HEIGHT=40>
<PARAM NAME="web_session_name_1"
VALUE="locis">
<PARAM NAME="web_session_url_1"
VALUE="http://www.acme.com/jet3270/sessions/locis">
<PARAM NAME="web_session_name_2"
VALUE="Accounts">
<PARAM NAME="web_session_url_1"
VALUE="http://www.acme.com/jet3270/sessions/acc">
<PARAM NAME="last_web_session"
VALUE="2">
Your Web Browser is not currently Java-enabled.
</APPLET>
The following table lists the JET 3270 applet parameters
| NAME |
VALUE type |
Default Value |
Description |
| alarm_audio |
File
name |
bell.au |
Audio
file that JET 3270 plays when it sounds
an alarm for users without saved preferences. |
| allowed_hostname |
Hostname or
IP address |
localhost |
Hostname
users are allowed to connect to when when
"disable_hostname_port" is "yes". |
| allowed_port |
Integer |
23 |
Port number of host
users are allowed to connect to when when
"disable_hostname_port" is "yes". |
| audio_enabled |
yes, no |
yes |
Whether
JET 3270 attempts to sound any alarms for
users without saved preferences. |
| debug |
yes, no |
no |
Provide debugging
and tracing information for users without saved
preferences. |
| disable_hostname_port |
yes, no |
no |
Disable the user's
ability to specify a host to connect to. |
| disable_new_window |
yes, no |
no |
Disable the user's
ability to create new JET 3270 windows. |
| disable_preferences |
yes, no |
no |
Disable the
display and modification of preferences. |
| disable_session_settings |
yes, no |
no |
Disable the
display and modification of session settings and the
use and saving of local sessions. |
| help_source |
One of:
--code_base
--custom |
code_base |
Location from which
help files are loaded for users without saved
preferences. |
| help_custom_url |
HTTP URL |
(no default) |
URL of location
from which help files are loaded if "help_source" is
"custom" for users without saved preferences. |
| ignore_meta_under_unix |
yes, no |
yes |
Whether JET
3270 ignores the Meta key when running under
Unix or Linux. |
| key_activity_timeout |
Integer |
0 |
Minutes JET
3270 waits before disconnecting due to no key
activity. |
| last_web_session
|
Integer |
-1 |
Number of the
highest numbered web session. |
| show_keyboard |
yes, no |
yes |
Whether
JET 3270 shows the on-screen keyboard for
users without saved preferences. |
| show_statusbar |
yes, no |
yes |
Whether
JET 3270 shows the status bar for users without
saved preferences. |
| show_toolbar |
yes, no |
yes |
Whether
JET 3270 shows the toolbar for users without
saved preferences. |
| startup_operation |
One of:
-- none
-- new_window
-- new_session
-- open_session
-- open_session_new_window
|
none |
What
JET 3270 does when it starts up for users
without saved preferences. |
| startup_session |
Session
name |
empty |
The
session opened if the startup operation is Open Session
or Open Session in New Window. |
| toolbar_size |
One of:
--small
--large
|
small |
Toolbar icon
size for users without saved preferences. |
| warn_unsupported_vm |
yes, no |
yes |
Display warning
if virtual machine is unsupported for users without saved
preferences. |
| web_session_name_x |
String |
empty |
The name of
web session number x. |
| web_session_url_x |
HTTP
or file URL |
empty |
The URL of
web session number x. |
If a parameter name is not specified correctly, or its
value is invalid, JET 3270 uses the default value for that
parameter.
