1 /*
2 * Copyright (c) 2006, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package netscape.javascript;
27
28 import jdk.internal.netscape.javascript.spi.JSObjectProvider;
29 import java.applet.Applet;
30 import java.security.AccessController;
31 import java.security.PrivilegedAction;
32 import java.util.Iterator;
33 import java.util.ServiceLoader;
34
35 /**
36 * <p>
37 * Allows Java code to manipulate JavaScript objects.
38 * </p>
39 *
40 * <p>
41 * When a JavaScript object is passed or returned to Java code, it
42 * is wrapped in an instance of {@code JSObject}. When a
43 * {@code JSObject} instance is passed to the JavaScript engine,
44 * it is unwrapped back to its original JavaScript object. The
45 * {@code JSObject} class provides a way to invoke JavaScript
46 * methods and examine JavaScript properties.
47 * </p>
48 *
49 * <p> Any data returned from the JavaScript engine to Java is
50 * converted to Java data types. Certain data passed to the JavaScript
51 * engine is converted to JavaScript data types.
52 * </p>
53 *
54 */
55 public abstract class JSObject {
56 /**
57 * Constructs a new JSObject. Users should neither call this method nor
58 * subclass JSObject.
59 */
60 protected JSObject() {
61 }
62
63 /**
64 * Calls a JavaScript method. Equivalent to
65 * "this.methodName(args[0], args[1], ...)" in JavaScript.
66 *
67 * @param methodName The name of the JavaScript method to be invoked.
68 * @param args the Java objects passed as arguments to the method.
69 * @return Result of the method.
70 * @throws JSException when an error is reported from the browser or
71 * JavaScript engine.
72 */
73 public abstract Object call(String methodName, Object... args) throws JSException;
74
75 /**
76 * Evaluates a JavaScript expression. The expression is a string of
77 * JavaScript source code which will be evaluated in the context given by
78 * "this".
79 *
80 * @param s The JavaScript expression.
81 * @return Result of the JavaScript evaluation.
82 * @throws JSException when an error is reported from the browser or
83 * JavaScript engine.
84 */
85 public abstract Object eval(String s) throws JSException;
86
87 /**
88 * Retrieves a named member of a JavaScript object. Equivalent to
89 * "this.name" in JavaScript.
90 *
91 * @param name The name of the JavaScript property to be accessed.
92 * @return The value of the propery.
93 * @throws JSException when an error is reported from the browser or
94 * JavaScript engine.
95 */
96 public abstract Object getMember(String name) throws JSException;
97
98 /**
99 * Sets a named member of a JavaScript object. Equivalent to
100 * "this.name = value" in JavaScript.
101 *
102 * @param name The name of the JavaScript property to be accessed.
103 * @param value The value of the propery.
104 * @throws JSException when an error is reported from the browser or
105 * JavaScript engine.
106 */
107 public abstract void setMember(String name, Object value) throws JSException;
108
109 /**
110 * Removes a named member of a JavaScript object. Equivalent
111 * to "delete this.name" in JavaScript.
112 *
113 * @param name The name of the JavaScript property to be removed.
114 * @throws JSException when an error is reported from the browser or
115 * JavaScript engine.
116 */
117 public abstract void removeMember(String name) throws JSException;
118
119 /**
120 * Retrieves an indexed member of a JavaScript object. Equivalent to
121 * "this[index]" in JavaScript.
122 *
123 * @param index The index of the array to be accessed.
124 * @return The value of the indexed member.
125 * @throws JSException when an error is reported from the browser or
126 * JavaScript engine.
127 */
128 public abstract Object getSlot(int index) throws JSException;
129
130 /**
131 * Sets an indexed member of a JavaScript object. Equivalent to
132 * "this[index] = value" in JavaScript.
133 *
134 * @param index The index of the array to be accessed.
135 * @param value The value to set
136 * @throws JSException when an error is reported from the browser or
137 * JavaScript engine.
138 */
139 public abstract void setSlot(int index, Object value) throws JSException;
140
141 /**
142 * Returns a JSObject for the window containing the given applet. This
143 * method only works when the Java code is running in a browser as an
144 * applet. The object returned may be used to access the HTML DOM directly.
145 *
146 * @param applet The applet.
147 * @return JSObject representing the window containing the given applet or
148 * {@code null} if we are not connected to a browser.
149 * @throws JSException when an error is reported from the browser or
150 * JavaScript engine or if applet is {@code null}
151 */
152 public static JSObject getWindow(Applet applet) throws JSException {
153 return ProviderLoader.callGetWindow(applet);
154 }
155
156 private static class ProviderLoader {
157 private static final JSObjectProvider provider;
158
159 static {
160 provider = AccessController.doPrivileged(
161 new PrivilegedAction<>() {
162 @Override
163 public JSObjectProvider run() {
164 Iterator<JSObjectProvider> providers =
165 ServiceLoader.loadInstalled(JSObjectProvider.class).iterator();
166 if (providers.hasNext()) {
167 return providers.next();
168 }
169 return null;
170 }
171 }
172 );
173 }
174
175 private static JSObject callGetWindow(Applet applet) {
176 if (provider != null) {
177 return provider.getWindow(applet);
178 }
179 return null;
180 }
181 }
182 }