JSObject.java revision 1590:1916a2c680d8 
1/*
2 * Copyright (c) 2010, 2013, 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
26package jdk.nashorn.api.scripting;
27
28import java.util.Collection;
29import java.util.Set;
30import jdk.nashorn.internal.runtime.JSType;
31
32/**
33 * This interface can be implemented by an arbitrary Java class. Nashorn will
34 * treat objects of such classes just like nashorn script objects. Usual nashorn
35 * operations like obj[i], obj.foo, obj.func(), delete obj.foo will be glued
36 * to appropriate method call of this interface.
37 *
38 * @since 1.8u40
39 */
40public interface JSObject {
41    /**
42     * Call this object as a JavaScript function. This is equivalent to
43     * 'func.apply(thiz, args)' in JavaScript.
44     *
45     * @param thiz 'this' object to be passed to the function
46     * @param args arguments to method
47     * @return result of call
48     */
49    public Object call(final Object thiz, final Object... args);
50
51    /**
52     * Call this 'constructor' JavaScript function to create a new object.
53     * This is equivalent to 'new func(arg1, arg2...)' in JavaScript.
54     *
55     * @param args arguments to method
56     * @return result of constructor call
57     */
58    public Object newObject(final Object... args);
59
60    /**
61     * Evaluate a JavaScript expression.
62     *
63     * @param s JavaScript expression to evaluate
64     * @return evaluation result
65     */
66    public Object eval(final String s);
67
68    /**
69     * Retrieves a named member of this JavaScript object.
70     *
71     * @param name of member
72     * @return member
73     */
74    public Object getMember(final String name);
75
76    /**
77     * Retrieves an indexed member of this JavaScript object.
78     *
79     * @param index index slot to retrieve
80     * @return member
81     */
82    public Object getSlot(final int index);
83
84    /**
85     * Does this object have a named member?
86     *
87     * @param name name of member
88     * @return true if this object has a member of the given name
89     */
90    public boolean hasMember(final String name);
91
92    /**
93     * Does this object have a indexed property?
94     *
95     * @param slot index to check
96     * @return true if this object has a slot
97     */
98    public boolean hasSlot(final int slot);
99
100    /**
101     * Remove a named member from this JavaScript object
102     *
103     * @param name name of the member
104     */
105    public void removeMember(final String name);
106
107    /**
108     * Set a named member in this JavaScript object
109     *
110     * @param name  name of the member
111     * @param value value of the member
112     */
113    public void setMember(final String name, final Object value);
114
115    /**
116     * Set an indexed member in this JavaScript object
117     *
118     * @param index index of the member slot
119     * @param value value of the member
120     */
121    public void setSlot(final int index, final Object value);
122
123    // property and value iteration
124
125    /**
126     * Returns the set of all property names of this object.
127     *
128     * @return set of property names
129     */
130    public Set<String> keySet();
131
132    /**
133     * Returns the set of all property values of this object.
134     *
135     * @return set of property values.
136     */
137    public Collection<Object> values();
138
139    // JavaScript instanceof check
140
141    /**
142     * Checking whether the given object is an instance of 'this' object.
143     *
144     * @param instance instance to check
145     * @return true if the given 'instance' is an instance of this 'function' object
146     */
147    public boolean isInstance(final Object instance);
148
149    /**
150     * Checking whether this object is an instance of the given 'clazz' object.
151     *
152     * @param clazz clazz to check
153     * @return true if this object is an instance of the given 'clazz'
154     */
155    public boolean isInstanceOf(final Object clazz);
156
157    /**
158     * ECMA [[Class]] property
159     *
160     * @return ECMA [[Class]] property value of this object
161     */
162    public String getClassName();
163
164    /**
165     * Is this a function object?
166     *
167     * @return if this mirror wraps a ECMAScript function instance
168     */
169    public boolean isFunction();
170
171    /**
172     * Is this a 'use strict' function object?
173     *
174     * @return true if this mirror represents a ECMAScript 'use strict' function
175     */
176    public boolean isStrictFunction();
177
178    /**
179     * Is this an array object?
180     *
181     * @return if this mirror wraps a ECMAScript array object
182     */
183    public boolean isArray();
184
185    /**
186     * Returns this object's numeric value.
187     *
188     * @return this object's numeric value.
189     * @deprecated use {@link #getDefaultValue(Class)} with {@link Number} hint instead.
190     */
191    @Deprecated
192    default double toNumber() {
193        return JSType.toNumber(JSType.toPrimitive(this, Number.class));
194    }
195
196    /**
197     * Implements this object's {@code [[DefaultValue]]} method as per ECMAScript 5.1 section 8.6.2.
198     *
199     * @param hint the type hint. Should be either {@code null}, {@code Number.class} or {@code String.class}.
200     * @return this object's default value.
201     * @throws UnsupportedOperationException if the conversion can't be performed. The engine will convert this
202     * exception into a JavaScript {@code TypeError}.
203     */
204    default Object getDefaultValue(final Class<?> hint) throws UnsupportedOperationException {
205        return DefaultValueImpl.getDefaultValue(this, hint);
206    }
207}
208