JavaScript: The Definitive Guide, Fourth Edition

LiveConnect Data Types

To understand how LiveConnect does its job of connecting JavaScript to Java, you have to understand the JavaScript data types that LiveConnect uses. The following sections explain these JavaScript data types. Although Internet Explorer uses a different technology, an understanding of how LiveConnect works will also help you understand the workings of IE. Some of the LiveConnect data types described here have analogs in IE.

The JavaPackage Class

A package in Java is collection of related Java classes. The JavaPackage class is a JavaScript data type that represents a Java package. The properties of a JavaPackage are the classes that the package contains (classes are represented by the JavaClass class, which we’ll see shortly), as well as any other packages that the package contains. There is a restriction on the JavaPackage class: you cannot use a JavaScript for/in loop to obtain a complete list of all packages and classes that a JavaPackage contains. This restriction is the result of an underlying restriction in the Java virtual machine.

All JavaPackage objects are contained within a parent JavaPackage; the Window property named Packages is a top-level JavaPackage that serves as the root of this package hierarchy. It has properties such as java, sun, and netscape, which are JavaPackage objects that represent the various hierarchies of Java classes that are available to the browser. For example, the JavaPackage Packages.java contains the JavaPackage ...