The Netscape packages

iveConnect has two applet API packages: netscape.javascript and netscape.plugin.

The netscape.javascript applet API package has the following classes:

• netscape.javascript.JSObject
• netscape.javascript.JSException

The netscape.plugin applet API package has the following classes:

• netscape.plugin.Plugin

The following sections describe these classes and list their constructors and methods.

netscape.javascript.JSObject

The public final class JSObject extends Object.

java.lang.Object
   |
   +----netscape.javascript.JSObject

JSObject allows Java to manipulate objects that are defined in JavaScript. Values passed from Java to JavaScript are converted as follows:

• JSObject is converted to the original JavaScript object.
• Any other Java object is converted to a JavaScript wrapper, which can be used to access methods and fields of the Java object. Converting this wrapper to a string will call the toString method on the original object, converting to a number will call the floatValue method if possible and fail otherwise. Converting to a boolean will try to call the booleanValue method in the same way.
• Java arrays are wrapped with a JavaScript object that understands array.length and array[index].
• A Java boolean is converted to a JavaScript boolean.
• Java byte, char, short, int, long, float, and double are converted to JavaScript numbers.

Values passed from JavaScript to Java are converted as follows:

• Objects that are wrappers around Java objects are unwrapped.
• Other objects are wrapped with a JSObject.
• Strings, numbers, and booleans are converted to String, Float, and Boolean objects respectively.

This means that all JavaScript values show up as some kind of java.lang.Object in Java. In order to make much use of them, you will have to cast them to the appropriate subclass of Object, as shown in the following examples:

(String) window.getMember("name")
(JSObject) window.getMember("document")

Note

If you call a Java method from JavaScript, this conversion happens automatically--you can pass in "int" argument and it works.

Methods and static methods

The netscape.javascript.JSObject class has the following methods:

Method	Description
call	Calls a JavaScript method
eval	Evaluates a JavaScript expression
getMember	Retrieves a named member of a JavaScript object
getSlot	Retrieves an indexed member of a JavaScript object
removeMember	Removes a named member of a JavaScript object
setMember	Sets a named member of a JavaScript object
setSlot	Sets an indexed member of a JavaScript object
toString	Converts a JSObject to a string

The netscape.javascript.JSObject class has the following static methods:

Method	Description
getWindow	Gets a JSObject for the window containing the given applet

The following sections show the declaration and usage of these methods.

call

Method. Calls a JavaScript method. Equivalent to "this.methodName(args[0], args[1], ...)" in JavaScript.

Declaration

public Object call(String methodName,
   Object args[])

eval

Method. Evaluates a JavaScript expression. The expression is a string of JavaScript source code which will be evaluated in the context given by "this".

Declaration

public Object eval(String s)

getMember

Method. Retrieves a named member of a JavaScript object. Equivalent to "this.name" in JavaScript.

Declaration

public Object getMember(String name)

getSlot

Method. Retrieves an indexed member of a JavaScript object. Equivalent to "this[index]" in JavaScript.

Declaration

public Object getSlot(int index)

getWindow

Static method. Returns a JSObject for the window containing the given applet.

Declaration

public static JSObject getWindow(Applet applet)

removeMember

Method. Removes a named member of a JavaScript object.

Declaration

public void removeMember(String name)

setMember

Method. Sets a named member of a JavaScript object. Equivalent to "this.name = value" in JavaScript.

Declaration

public void setMember(String name,
   Object value)

setSlot

Method. Sets an indexed member of a JavaScript object. Equivalent to "this[index] = value" in JavaScript.

Declaration

public void setSlot(int index,
   Object value)

toString

Method. Converts a JSObject to a String.

Overrides: toString in class Object

Declaration

public String toString()

netscape.javascript.JSException

The public class JSException extends Exception.

java.lang.Object
   |
   +----java.lang.Throwable
           |
           +----java.lang.Exception
                   |
                    +----netscape.javascript.JSException

JSException is an exception that is thrown when JavaScript code returns an error.

Constructors

The netscape.javascript.JSException class has the following constructors:

Constructor	Description
JSException	Constructs a JSException. You specify whether the JSException has a detail message and other information.

The following sections show the declaration and usage of these constructors.

JSException

Constructor. Constructs a JSException. You specify whether the JSException has a detail message and other information.

Declaration

1. public JSException()

2. public JSException(String s)

3. public JSException(String s,
   String filename,
   int lineno,
   String source,
   int tokenIndex)

Arguments

s is the detail message.

filename is the URL of the file where the error occurred, if possible.

lineno is the line number if the file, if possible.

source is the string containing the JavaScript code being evaluated.

tokenIndex is the index into the source string where the error occurred.

Description

A detail message is a string that describes this particular exception.

Each form constructs a JSException with different information:

• Form 1 of the declaration constructs a JSException without a detail message.
• Form 2 of the declaration constructs a JSException with a detail message.
• Form 3 of the declaration constructs a JSException with a detail message and all the other information that usually comes with a JavaScript error.

netscape.plugin.Plugin

The public class Plugin extends Object.

java.lang.Object
   |
   +----netscape.plugin.Plugin

This class represents the Java reflection of a plug-in. Plug-ins that need to have Java methods associated with them should subclass this class and add new (possibly native) methods to it. This allows other Java entities (such as applets and JavaScript code) to manipulate the plug-in.

Constructors and methods

The netscape.plugin.Plugin class has the following constructors:

Constructor	Description
Plugin	Constructs a Plugin.

The netscape.plugin.Plugin class has the following methods:

Method	Description
destroy	Called when the plug-in is destroyed
getPeer	Returns the native NPP object--the plug-in instance that is the native part of a Java Plugin object
getWindow	Returns the JavaScript window on which the plug-in is embedded
init	Called when the plug-in is initialized
isActive	Determines whether the Java reflection of a plug-in still refers to an active plug-in

The following sections show the declaration and usage of these constructors and methods.

destroy

Method. Called when the plug-in is destroyed. You never need to call this method directly, it is called when the plug-in is destroyed. At the point this method is called, the plug-in will still be active.

Declaration

public void destroy()

See also

init

getPeer

Method. Returns the native NPP object--the plug-in instance that is the native part of a Java Plugin object. This field is set by the system, but can be read from plug-in native methods by calling:

NPP npp = (NPP)netscape_plugin_Plugin_getPeer(env, thisPlugin);

Declaration

public int getPeer()

getWindow

Method method. Returns the JavaScript window on which the plug-in is embedded.

Declaration

public JSObject getWindow()

init

Method. Called when the plug-in is initialized. You never need to call this method directly, it is called when the plug-in is created.

Declaration

public void init()

See also

destroy

isActive

Method. Determines whether the Java reflection of a plug-in still refers to an active plug-in. Plug-in instances are destroyed whenever the page containing the plug-in is left, thereby causing the plug-in to no longer be active.

Declaration

public boolean isActive()

Plugin

Constructor. Constructs a Plugin.

Declaration

public Plugin()