Class JSObject

public abstract class JSObject
extends Object

Allows Java code to manipulate JavaScript objects.

When a JavaScript object is passed or returned to Java code, it is wrapped in an instance of JSObject. When a JSObject instance is passed to the JavaScript engine, it is unwrapped back to its original JavaScript object. The JSObject class provides a way to invoke JavaScript methods and examine JavaScript properties.

Any data returned from the JavaScript engine to Java is converted to Java data types. Certain data passed to the JavaScript engine is converted to JavaScript data types.

Constructors

Modifier Constructor Description
protected JSObject()

Constructs a new JSObject.

Methods

Modifier and Type Method Description
abstract Object call​(String methodName, Object... args)

Calls a JavaScript method.
abstract Object eval​(String s)

Evaluates a JavaScript expression.
abstract Object getMember​(String name)

Retrieves a named member of a JavaScript object.
abstract Object getSlot​(int index)

Retrieves an indexed member of a JavaScript object.
static JSObject getWindow​(Applet applet)

Deprecated.

The Applet API is deprecated.
abstract void removeMember​(String name)

Removes a named member of a JavaScript object.
abstract void setMember​(String name, Object value)

Sets a named member of a JavaScript object.
abstract void setSlot​(int index, Object value)

Sets an indexed member of a JavaScript object.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructors

JSObject

protected JSObject()

Constructs a new JSObject. Users should neither call this method nor subclass JSObject.

Methods

call

public abstract Object call(String methodName,
                            Object... args)
                     throws JSException

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

Parameters:
methodName - The name of the JavaScript method to be invoked.
args - the Java objects passed as arguments to the method.
Returns:
Result of the method.
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

eval

public abstract Object eval(String s)
                     throws JSException

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

Parameters:
s - The JavaScript expression.
Returns:
Result of the JavaScript evaluation.
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

getMember

public abstract Object getMember(String name)
                          throws JSException

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

Parameters:
name - The name of the JavaScript property to be accessed.
Returns:
The value of the propery.
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

setMember

public abstract void setMember(String name,
                               Object value)
                        throws JSException

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

Parameters:
name - The name of the JavaScript property to be accessed.
value - The value of the propery.
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

removeMember

public abstract void removeMember(String name)
                           throws JSException

Removes a named member of a JavaScript object. Equivalent to "delete this.name" in JavaScript.

Parameters:
name - The name of the JavaScript property to be removed.
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

getSlot

public abstract Object getSlot(int index)
                        throws JSException

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

Parameters:
index - The index of the array to be accessed.
Returns:
The value of the indexed member.
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

setSlot

public abstract void setSlot(int index,
                             Object value)
                      throws JSException

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

Parameters:
index - The index of the array to be accessed.
value - The value to set
Throws:
JSException - when an error is reported from the browser or JavaScript engine.

getWindow

@Deprecated(since="9")
public static JSObject getWindow(Applet applet)
                          throws JSException
Deprecated.
The Applet API is deprecated. See the java.applet package documentation for further information.

Returns a JSObject for the window containing the given applet. This method only works when the Java code is running in a browser as an applet. The object returned may be used to access the HTML DOM directly.

Parameters:
applet - The applet.
Returns:
JSObject representing the window containing the given applet or null if we are not connected to a browser.
Throws:
JSException - when an error is reported from the browser or JavaScript engine or if applet is null

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/11/docs/api/jdk.jsobject/netscape/javascript/JSObject.html