https://openjdk.java.net/ 
/*
 * Copyright (c) 2006, 2016, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package netscape.javascript;

import jdk.internal.netscape.javascript.spi.JSObjectProvider;
import java.applet.Applet;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Iterator;
import java.util.ServiceLoader;



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.



/**
 * <p>
 * Allows Java code to manipulate JavaScript objects.
 * </p>
 *
 * <p>
 * When a JavaScript object is passed or returned to Java code, it
 * is wrapped in an instance of {@code JSObject}. When a
 * {@code JSObject} instance is passed to the JavaScript engine,
 * it is unwrapped back to its original JavaScript object. The
 * {@code JSObject} class provides a way to invoke JavaScript
 * methods and examine JavaScript properties.
 * </p>
 *
 * <p> 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.
 * </p>
 *
 */
@SuppressWarnings("deprecation")
public abstract class JSObject {
    
Constructs a new JSObject. Users should neither call this method nor
subclass JSObject.

/**
     * Constructs a new JSObject. Users should neither call this method nor
     * subclass JSObject.
     */
    protected JSObject()  {
    }

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

Params:
  • methodName – The name of the JavaScript method to be invoked.
  • args – the Java objects passed as arguments to the method.
Throws:
  • JSException – when an error is reported from the browser or
JavaScript engine.
Returns:Result of the method.
/**
     * Calls a JavaScript method. Equivalent to
     * "this.methodName(args[0], args[1], ...)" in JavaScript.
     *
     * @param methodName The name of the JavaScript method to be invoked.
     * @param args the Java objects passed as arguments to the method.
     * @return Result of the method.
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract Object call(String methodName, Object... args) 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".

Params:
  • s – The JavaScript expression.
Throws:
  • JSException – when an error is reported from the browser or
JavaScript engine.
Returns:Result of the JavaScript evaluation.
/**
     * Evaluates a JavaScript expression. The expression is a string of
     * JavaScript source code which will be evaluated in the context given by
     * "this".
     *
     * @param s The JavaScript expression.
     * @return Result of the JavaScript evaluation.
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract Object eval(String s) throws JSException;

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

Params:
  • name – The name of the JavaScript property to be accessed.
Throws:
  • JSException – when an error is reported from the browser or
JavaScript engine.
Returns:The value of the propery.
/**
     * Retrieves a named member of a JavaScript object. Equivalent to
     * "this.name" in JavaScript.
     *
     * @param name The name of the JavaScript property to be accessed.
     * @return The value of the propery.
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract Object getMember(String name) throws JSException;

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

Params:
  • 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.
/**
     * Sets a named member of a JavaScript object. Equivalent to
     * "this.name = value" in JavaScript.
     *
     * @param name The name of the JavaScript property to be accessed.
     * @param value The value of the propery.
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract void setMember(String name, Object value) throws JSException;

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

Params:
  • name – The name of the JavaScript property to be removed.
Throws:
  • JSException – when an error is reported from the browser or
JavaScript engine.
/**
     * Removes a named member of a JavaScript object. Equivalent
     * to "delete this.name" in JavaScript.
     *
     * @param name The name of the JavaScript property to be removed.
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract void removeMember(String name) throws JSException;

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

Params:
  • index – The index of the array to be accessed.
Throws:
  • JSException – when an error is reported from the browser or
JavaScript engine.
Returns:The value of the indexed member.
/**
     * Retrieves an indexed member of a JavaScript object. Equivalent to
     * "this[index]" in JavaScript.
     *
     * @param index The index of the array to be accessed.
     * @return The value of the indexed member.
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract Object getSlot(int index) throws JSException;

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

Params:
  • 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.
/**
     * Sets an indexed member of a JavaScript object. Equivalent to
     * "this[index] = value" in JavaScript.
     *
     * @param index The index of the array to be accessed.
     * @param value The value to set
     * @throws JSException when an error is reported from the browser or
     * JavaScript engine.
     */
    public abstract void setSlot(int index, Object value) throws JSException;

    
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.

Params:
  • applet – The applet.
Throws:
  • JSException – when an error is reported from the browser or JavaScript engine or if applet is null
Returns:JSObject representing the window containing the given applet or null if we are not connected to a browser.
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.
     *
     * @param applet The applet.
     * @return JSObject representing the window containing the given applet or
     * {@code 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 {@code null}
     *
     * @deprecated  The Applet API is deprecated. See the
     * <a href="{@docRoot}/java.desktop/java/applet/package-summary.html">
     * java.applet package documentation</a> for further information.
     */

    @Deprecated(since = "9")
    @SuppressWarnings("exports")
    public static JSObject getWindow(Applet applet) throws JSException {
        return ProviderLoader.callGetWindow(applet);
    }

    private static class ProviderLoader {
        private static final JSObjectProvider provider;

        static {
            provider = AccessController.doPrivileged(
                new PrivilegedAction<>() {
                    @Override
                    public JSObjectProvider run() {
                        Iterator<JSObjectProvider> providers =
                            ServiceLoader.loadInstalled(JSObjectProvider.class).iterator();
                        if (providers.hasNext()) {
                            return providers.next();
                        }
                        return null;
                    }
                }
            );
        }

        private static JSObject callGetWindow(Applet applet) {
            if (provider != null) {
                return provider.getWindow(applet);
            }
            return null;
        }
    }
}