Using CAB and ZIP Files with the Ultimate Button Bar

sing CAB and ZIP Files

Included with the Ultimate Button Bar^TMJava class files are a number of files with the extension "cab" or "zip". These files can be used to shorten the time it takes a browser to load the Java class files.

AB Files

CAB files (short for CABinet files) are files that store multiple Java class files in a compressed format in a single file. You indicate to a browser that a CAB file is available by using the CABBASE parameter in the applet tag. When a browser that supports CAB files sees the CABBASE parameter, the browser will load the single CAB file instead of loading each Java class file separately. This improves the load time in two ways: first, only one network connection must be made (as opposed to one network connection for each class file), and second, since the class files are compressed, there is less data that must be transferred over the network.

The CAB format was developed by Microsoft, and Internet Explorer version 3.0 or higher supports the CABBASE parameter.

To use a CAB file, include the CABBASE parameter in the APPLET HTML tag. For example:

<APPLET CODEBASE="../../../Java" CODE="LiteTextURLButtonBar.class" WIDTH="376" HEIGHT="32"> <PARAM NAME="cabbase" VALUE="ButtonBarAll.cab"> [ ... rest of applet parameters follow... ] </APPLET>

The regular Java class files should be stored along with the CAB file so that browsers that support Java but that do not support CAB files will still be able to run the Java applet.

IP Files

A ZIP file contains multiple Java class files, but in an uncompressed format. You indicate to a browser that a ZIP file is available by using the ARCHIVE parameter in the applet tag. When a browser that supports ZIP files sees the ARCHIVE parameter, the browser will load the single ZIP file instead of loading each Java class file separately. Using a ZIP file improves the load time because only one network connection must be made (as opposed to one network connection for each class file).

Note that a ZIP file behaves differently than a CAB file in that if the browser cannot find a Java class file in the ZIP file, it will search for the Java class file in the traditional manner. If a CAB file is used, then all Java classes that the applet uses must be found in the CAB file, or the applet will not run.

ZIP files are supported by Netscape Navigator version 3.0 or higher.

To use a ZIP file, include the ARCHIVE parameter in the APPLET HTML tag. For example:

<APPLET CODEBASE="../../../Java" CODE="LiteTextURLButtonBar.class" WIDTH="376" HEIGHT="32"> <PARAM NAME="archive" VALUE="ButtonBarAll.zip"> [ ... rest of applet parameters follow... ] </APPLET>

The regular Java class files should be stored along with the ZIP file so that browsers that support Java but that do not support ZIP files will still be able to run the Java applet.

sing CAB and ZIP Files Together

You can include both the CABBASE and the ARCHIVE parameter in the applet tag. This will allow browsers that support either a CAB file or a ZIP file to optimize the loading of Java classes.

Below is an example of using both parameters:

<APPLET CODEBASE="../../../Java" CODE="LiteTextURLButtonBar.class" WIDTH="376" HEIGHT="32"> <PARAM NAME="cabbase" VALUE="ButtonBarAll.cab"> <PARAM NAME="archive" VALUE="ButtonBarAll.zip"> [ ... rest of applet parameters follow... ] </APPLET>

Be sure to include the regular Java class files with the CAB file and the ZIP file so that browsers that support Java but that do not support a CAB or a ZIP file will still be able to run the Java applet.

ontents of the CAB and ZIP Files

The following is a breakdown of what Java classes are included in each of the included CAB and ZIP files.

You should only need one CAB and one ZIP file for all of the button bars on your web site. Choose the pair that contains only the functionality that you will use. For instance, if you will use only image based button bars, then pick ButtonBarImg.cab and ButtonBarImg.zip. If you will use image based button bars and simple text based button bars, then choose ButtonBarImgLTxt.cab and ButtonBarImgLTxt.zip.

Note that the CABBASE and ARCHIVE parameters will always point to the same CAB or ZIP file. If you are using ButtonBarImgLTxt.cab and ButtonBarImgLTxt.zip, then you would set the CODE parameter of the APPLET tag to the particular class that the button bar actually uses (e.g., ImageURLButtonBar.class or LiteTextURLButtonBar.class).

ButtonBarImg.cab ButtonBarImg.zip	ButtonBar.class ButtonBarObserver.class ButtonRegion.class ButtonAnimate.class ImageURLButtonBar.class
ButtonBarImgTxt.cab ButtonBarImgTxt.zip	ButtonBar.class ButtonBarObserver.class ButtonRegion.class ButtonAnimate.class ImageURLButtonBar.class TextURLButtonBar.class
ButtonBarImgLTxt.cab ButtonBarImgLTxt.zip	ButtonBar.class ButtonBarObserver.class ButtonRegion.class ButtonAnimate.class ImageURLButtonBar.class LiteTextURLButtonBar.class
ButtonBarTxt.cab ButtonBarTxt.zip	ButtonBar.class ButtonBarObserver.class ButtonRegion.class ButtonAnimate.class TextURLButtonBar.class
ButtonBarLTxt.cab ButtonBarLTxt.zip	ButtonBar.class ButtonBarObserver.class ButtonRegion.class ButtonAnimate.class LiteTextURLButtonBar.class
ButtonBarAll.cab ButtonBarAll.zip	ButtonBar.class ButtonBarObserver.class ButtonRegion.class ButtonAnimate.class ImageURLButtonBar.class TextURLButtonBar.class LiteTextURLButtonBar.class