1/*
2 * Copyright (c) 2015, 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 jdk.nashorn.internal.runtime.JSType;
29
30/**
31 * Default implementation of {@link JSObject#getDefaultValue(Class)}. Isolated into a separate class mostly so
32 * that we can have private static instances of function name arrays, something we couldn't declare without it
33 * being visible in {@link JSObject} interface.
34 */
35class DefaultValueImpl {
36    private static final String[] DEFAULT_VALUE_FNS_NUMBER = new String[] { "valueOf", "toString" };
37    private static final String[] DEFAULT_VALUE_FNS_STRING = new String[] { "toString", "valueOf" };
38
39    static Object getDefaultValue(final JSObject jsobj, final Class<?> hint) throws UnsupportedOperationException {
40        final boolean isNumber = hint == null || hint == Number.class;
41        for(final String methodName: isNumber ? DEFAULT_VALUE_FNS_NUMBER : DEFAULT_VALUE_FNS_STRING) {
42            final Object objMember = jsobj.getMember(methodName);
43            if (objMember instanceof JSObject) {
44                final JSObject member = (JSObject)objMember;
45                if (member.isFunction()) {
46                    final Object value = member.call(jsobj);
47                    if (JSType.isPrimitive(value)) {
48                        return value;
49                    }
50                }
51            }
52        }
53        throw new UnsupportedOperationException(isNumber ? "cannot.get.default.number" : "cannot.get.default.string");
54    }
55}
56